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DEPARTMENT OF THE ARMY FIELD MANUAL
REGRADEO UNCLASSIFIED ByAU'.TY 1O00 DIR. 5200. 1 r
105 - nmHOWITZERM2 - SERIES
TOWED
DEPARTMENT OF THE ARMY * AUGUST 1952
-- UNCLASSIFIED
DEPARTMENT OF THE ARMY FIELD MANUAL
FM 6-75
This manual supersedes FM 6-75, 5 October 1945,including C1, 24 January 1947
105 - mmHOWITZERM2 - SERIES
TOWED
DEPARTMENT OF THE ARMY · AUGUST 1952
United States Government Printing Office
Washington : 1952
DEPARTMENT OF THE ARMY
WASHINGTON 25, D. C., 7 August 1952
FM 6-75 is published for the information and guidanceof all concerned.
lAG 300.7 (28 Jun 52)]
BY ORDER OF THE SECRETARY OF THE ARMY:
OFFICIAL: J. LAWTON COLLINS
WM. E. BERGIN Chief of StaffMajor General, USA United States ArmyThe Adjutant General
DISTRIBUTION:
Active Army:Tech Svc (1); Tech Svc Bd (2); AFF (10);
AA Comd (2); OS Maj Comd (10); Base Comd(5); MDW (2); Log Comd (2); A (2); CHQ(2); Div (5); Brig 6 (2); Regt 6 (2); USMA(5); C & GSC (2); Sch (2) except 6 (500);RTC 6 (100); FT (1); PRGR 9 (2); T/O& E's: 6-25N (25); 6-225 (25).
NG: Div (2); Brig .6 (2); Regt 6 (2); T/O & E6-25N (2), 6-225 (2).
ORC: Div (2); Brig 6 (2); Regt 6 (2); T/O & E6-25N (2), 6-225 (2).
For explanation of distribution formula, see SR310-90-1.
CONTENTS
Paragraphs Page
CHAPTER 1. GENERAL .................... 1- 3 1
2. ORGANIZAT:ON ............... 4, 5 5CHAPTER 3. SECTION DRILL.
Section 1. General .................... 6, 7 7II. Preliminary commands and 8-13 9
formations.CHAPTER 4. PREPARING THE GUN FOR FIRING
AND TRAVELING.
Section I. Preparations for firing ..... 14-17 18II. Preparations for traveling .. 18, 19 23
CHAPTER 5. DUTIES IN FIRING.
Section I. Indirect laying............. 20-29 26II. Direct laying, general ....... 30-33 70
III. Direct laying, two-man two- 34-38 84sight system.
IV. Direct laying, one-man, one- 39-42 91sight system.
CHAPTER 6. TECHNIQUES AND SITUATIONS THAT 43-51 95REQUIRE SPECIAL ATTENTION.
CHAPTER 7. BORE SIGHTING AND BASIC PERI-
ODIC TESTS.
Section I. General .................... 52, 53 110II. Bore sighting .............. 54-58 113
III. Basic periodic tests ......... 59-64 145
CHAPTER 8. MAINTENANCE AND INSPECTIONS. 65-75 158
9. DECONTAMINATION OF EQUIPMENT. 76-79 171
10. DESTRUCTION OF EQUIPMENT..... 80-82 17411. SAFETY PRECAUTIONS .......... 83-86 176
APPENDIX I. REFERENCES ...................... 179II. TRAINING ........................ 172
INDEX ... .................. ............ 221
This manual supersedes FM 6-755 October 1945, including C1, 24 January 1947
CHAPTER 1
GENERAL
1. PURPOSE AND SCOPE
This manual is a guide to assist commandersin developing the sections of towed 105-mm how-itzer firing batteries into efficient teams that havea sense of discipline that will impel them to oper-ate effectively under the stress of battle. Thismanual prescribes individual duties and sectiondrills, inspection and maintenance drills, tests andadjustments for sighting and fire control equip-ment, and methods for the destruction and decon-tamination of equipment.
2. DEFINITIONS AND TERMS
a. Gun. Throughout this manual the term gunis used generally to include howitzer.
b. Section. Tables of organization and equip-ment prescribe the personnel and equipment com-prising each section of a battery (figs. 1 and 2).In this manual the term section is often used todesignate only the personnel required to serve thegun and equipment of one section.
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c. Coupled. A gun is coupled when it is attachedto its prime mover and all braking and lightingconnections are in place.
d. Uncoupled. A gun is uncoupled when it isdetached from its prime mover.
e. Front. The front of a section, gun coupled,is the direction in which the prime mover isheaded; with the gun uncoupled, front is the direc-tion in which the muzzle points.
f. Right (left). The direction right (left) isthe right (left) when facing to the front.
g. In Battery. A gun is said to be in batterywhen its tube is in normal firing position.
3. REFERENCES
Publications pertaining to the 105-mm how-itzer, towed, and auxiliary equipment, coveringrelated matters not discussed in detail in thismanual, are listed in appendix I.
4
4wNFation
CHAPTER 2
ORGANIZATION
'4. COMPOSITION OF THE GUN SECTION
a. The gun section consists of section person-nel, gun, prime mover, and auxiliary equipment.
b. The personnel of the gun section consists of:(1) A chief of section (CS).(2) A gunner (G).(3) Seven cannoneers, numbered from 1 to
7. Number 1 cannoneer is the assistantgunner.
(4) A driver (D).c. Section equipment is listed in T/O&E's and
SNL's appropriate to the weapon and unit(app. I).
5. GENERAL DUTIES OF PERSONNEL
a. Chief of Section. The chief of section is thenoncommissioned officer in command of the sec-tion. As such he is responsible to the batteryexecutive for-
(1) Training and efficiency of personnel.(2) Performance of duties listed under sec-
tion drill; duties in firing, testing and
-511)
_nitormation
adjustment of sighting and fire controlequipment; and inspection and mainte-nance of all section equipment, includingthe prime mover.
(3) Observance of safety precautions.(4) Preparation of field fortifications for
protection of equipment, ammunition,and personnel.
(5) Camouflage discipline; local security;and radiological, biological, and chemi-cal security discipline.
(6) Maintenance of the gun book.(7) Police of the section area.
b. Gunner. The gunner is the assistant to thesection chief in carrying out the duties specifiedin a above. The gunner's specific duties are pre-scribed in the appropriate chapters of this manual.
c. Cannoneers. Cannoneers perform duties aslisted in this manual, and any other duties thatthe chief of section prescribes.
d. Driver. The driver's primary duties aredriving and maintenance of the prime mover. Heremains with the prime mover unless other dutiesare designated.
CHAPTER 3
SECTION DRILL
Section I. GENERAL
6. OBJECTIVE
The objective of section drill is the attainmentof efficiency: Maximum precision coupled withhigh speed.
7. INSTRUCTIONS
a. To develop maximum efficiency and to pre-vent injuries to personnel and equipment, thedrills prescribed in this manual must be observed.Section drill should be conducted in silence exceptfor commands and reports. The section must bedrilled until reactions to commands are automatic,rapid, and efficient.
b. Mistakes are corrected immediately. Eachmember of the section must be impressed withthe importance of reporting promptly to the chiefof section any mistakes discovered after the com-mand to fire has been given. The chief of sectionwill report mistakes immediately to the executive.
-7_ i ~~7-
amm~r~jon .
c. Battery officers supervise the drill to insurethat instructions are carried out and that maxi-mum efficiency is obtained.
d. Duties should be rotated during training sothat each member of the gun section can performall the duties within the section. In addition, bat-tery overhead personnel not assigned specificduties during drill periods should be trained inthe fundamentals of section drill so that they willbe capable of functioning efficiently with a gunsection if required.
Figure 3. Section in formation.
8
e ormat ion
Section II. PRELIMINARY COMMANDSAND FORMATIONS
8. TO FORM THE SECTION
a. To Fall In. The chief of section takes hispost. On the command of execution the sectionforms in a single rank at close interval centeredon and facing the chief of section at a distanceof 3 paces (fig. 3). Higher numbered cannoneers,
Figure 4. Section formed in front of the gun, gun coupled.
9
if present, form in order between No. 7 and thedriver. The chief of section may indicate in hispreparatory command the place and directionmost suitable to form the section for a particularsituation. At the first formation for a drill orexercise the caution, "As gun section(s)," pre-cedes the command. The commands are: 1. FALLIN; (or 1. IN FRONT (REAR) OF YOUR GUN(S),
2. FALL IN; or 1. ON THE ROAD FACING THE
PARK,) 2. FALL IN. The gun section moves atdouble time and forms at close interval, at atten-tion, guiding on the gunner (figs. 3, 4, and 5).
71 6 L5 4
Figure 5. Section formed in rear of the gun,gun uncoupled.
10
u-n
b. To Call Off. The section being in formation,the command is: CALL OFF. Execution is asfollows:
(1) At the command all personnel in rank,except the gunner, execute eyes right.
(2) The section then calls off in sequence:"Gunner," "1," "2," "3," "4," "5," "6,""7," "Driver." As each man calls out hisdesignation he turns his head and eyessmartly to the front.
9. POSTS OF SECTION
The command is: 1. CANNONEERS, 2. POSTS.The command is general and is applicable whetherthe section is in or out of ranks and at a halt ormarching. All movements are executed at doubletime and are terminated at the position of atten-tion. Higher numbered cannoneers, if present,take posts as prescribed by the chief of section.
a. Gun Coupled. The section moves to posts asshown in figure 6. All personnel face to the frontand are alined 2 feet outside the prime mover.
b. Gun Uncoupled, Not Prepared for Action.The section moves to posts as shown in figure 7.All personnel face to the front and are aligned2 feet outside the wheels.
c. Gun Prepared for Action. The section movesto posts as shown in figure 8. All personnel faceto the front except the chief of section who facesthe executive unless otherwise indicated.
s ~11
SeslBation
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64
Figure 7. Posts, gun uncoupled, not prepared for action.
Figure 8. Posts, gun prepared for action.
Figure 8. Posts, gun prepared for action.213618°--52 2
13
S Iion
10. TO CHANGE POSTS
To acquaint the members of the section withall duties and to lend variety to drill, posts shouldbe changed frequently. The section being in for-mation, the commands are: 1. CHANGE POSTS,
2. MARCH, or 1. SECTION, CHANGE POSTS, 2.MARCH.
a. At 1. CHANGE POSTS, 2. MARCH, only thenumbered cannoneers change posts. No. 7 (orthe highest numbered cannoneer) moves at dou-ble time in rear of the section to the post of No. 1.All numbered cannoneers take 2 left steps thusplacing them at the post of the next higher num-bered cannoneer.
b. At 1. SECTION, CHANGE POSTS, 2. MARCH,the driver (or the leftmost man) moves at doubletime in rear of the section to the post of thegunner. The gunner and all other men in linetake 2 left steps as in a above.
11. TO MOUNT
The commands are: 1. PREPARE TO MOUNT,
2. MOUNT, or 1. MOUNT.a. At the command 1. PREPARE TO MOUNT, the
section moves at double time to positions shownin figure 6. At MOUNT, all members of the sec-tion mount and take seats as shown in figure 9.Each cannoneer is assisted by the one directlybehind (or in front in the case of the last can-
14 _
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L 'uC~~~~~~'
noneer in column) to insure rapid mounting andto prevent injuries. Before the commander ofthe vehicle and the driver mount, they verify thatthe load is properly coupled, that personnel andequipment are aboard, and that the tail gate andsafety strap are secure. If any members of thesection are to remain dismounted, their designa-tion is announced with the caution "stand fast"between the preparatory command and the com-mand of execution. For example: 1. PREPARE TOMOUNT, "driver stand fast," 2. MOUNT.
b. If the command is: 1. MOUNT, the sectionexecutes without pausing all that has been pre-scribed for the command 1. PREPARE TO MOUNT,
2. MOUNT.
12. TO DISMOUNT
The commands are: 1. PREPARE TO DISMOUNT,2. DISMOUNT, or 1. DISMOUNT.
a. At the preparatory command the membersof the section stand, if appropriate, and makepreparations to dismount quickly. At the com-mand of execution members of the section jumpto the ground and take posts as shown in figure 6.
b. If the command is: 1. DISMOUNT, the sec-tion executes without pausing all that has beenprescribed for the command 1. PREPARE TO DIS-MOUNT, 2. DISMOUNT.
16
13. TO FALL OUT
a. At Drill. When it is desired to give the sec-tion a rest from drill or relieve them temporarilyfrom a formation or post, the command FALLOUT is given. The command may be given at anytime, and infers that the section is to remain inthe vicinity of the drill area.
b. When Firing. When firing has been sus-pended temporarily, but it is desired to have thesection remain in the vicinity of the gun, thecommand FALL OUT is given. Men stand clearof the gun to insure that settings and layingremain undisturbed. During these periods thechief of section may direct his men to improvethe position, to replenish ammunition, or to doother necessary work.
_ _ 17 17
CHAPTER 4
PREPARING THE GUN FOR FIRINGAND TRAVELING
Section I. PREPARATIONS FOR FIRING
14. TO UNCOUPLE
The command is: UNCOUPLE. At the com-mand, members of the section take positions asshown in figure 10 and execute the following:
a. The gunner disconnects the blackout light-system from the prime mover. No. 1 removes theblackout light-system from the gun and places itin the section chest. The gunner and No. 1 thenhasten to the wheels nearest their respective posts.
b. Nos. 2, 3, 6, and 7 hasten to the trail hand-rails, even-numbered cannoneers on' the left, odd-numbered cannoners on the right with respectto the tube.
c. Nos. 4 and 5 go to the muzzle of the gunand assist by placing their weight on the tube.
d. No. 2 unlatches the pintle and, assisted byNos. 3, 6, and 7, lifts the lunette from the pintle.
e. Nos. 2, 3, 4, 5, 6, and 7 move the gun to thedesired location.
f. Nos. 2, 3, 6, and 7 then lower the trails to the
18
FRONT is given, No. 4 sets the left handbrake
2I 6
Figure gu10. iSection uncoupl turned 180in a clockwisng) the direcgun.
ground. Nos. 4 and 5 set the left and right hand-
b. Action Right (Left). The command is:ACTION RIGHT (LEFT). The movement isexecuted as in ACTION FRONT, except thatafter the gun is uncoupled, the trail is turned 900in the appropriate direction, and the gun is movedforward to clear the track of the prime mover(par. 2f).
A-Ri .Ts
16. MOVEMENT OF GUN BY HAND
The commands are: 1 GUN (S) FORWARD (BACK-
WARD) 2. MARCH. Execution is as follows:a. At command GUN(S) FORWARD (BACKWARD)
the following actions are taken:
(1) The gunner and No. 1 remove the leftand right trail lock pins respectively, andplace the pins in traveling position. Theythen move to the wheels of the gun andassist in moving the gun.
(2) Nos. 2 and 6 on the left trail and Nos.3 and 7 on the right trail manipulatethe trails as directed by No 4, so thatthe axle locks may be locked by Nos. 4and 5, working on the left and rightrespectively.
(3) Nos. 2, 3, 6, and 7 close the trails; No. 6,assisted by No. 7, fastens the trail lock.
(4) Nos. 4 and 5 release the handbrakes.(5) Nos. 2 and 6 grasp the trail handrails
on the left and Nos. 3 and 7 grasp thetrail handrails on the right.
(6) No. 4 and No. 5 ride the muzzle in orderto balance the gun.
(7) Higher-numbered cannoneers, if present,are employed as directed by the chief ofsection. If the situation requires addi-tional manpower, Nos. 4 and 5, under thedirection of the chief of section, will
20 _
illlll 1tion
obtain prolonges and attach them to thehooks on the left and right axles, re-spectively. Personnel designated by thebattery executive to assist in movementof the gun will take position and pull onthe prolonges as directed by the chief ofsection.
i 2 6 4
Figure 11. Section moving gun forward.
b. At the command MARCH, all move the gunforward (backward) under the direction of thechief of section (fig. 11). When the gun is beingmoved up or down steep slopes, Nos. 4 and 5assist by alternatingly setting and releasing theleft and right brakes, permitting the gun to bepivoted about the alternately braked wheels, thusthe gun is moved in a zigzag manner. OtherwiseNos. 4 and 5 ride the tube for balance.
21
c. At the command HALT, the gun is stoppedand reestablished in the firing position and allpersonnel resume their posts (par. 9c and fig. 8).
17. TO PREPARE FOR ACTION
a. The gun being in position uncoupled, thecommand is: PREPARE FOR ACTION (figs. 12and 13). If PREPARE FOR ACTION has notbeen ordered by the executive before the gun isestablished in the firing position, the commandis habitually given by the chief of section as soonas the gun has been uncoupled. After completionof designated duties personnel take posts (fig. 8).If PREPARE FOR ACTION is not desired, thecaution DO NOT PREPARE FOR ACTION mustbe given.
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Figure 12. Preparing for action prior to spreading trails.
22
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Figure 13. Preparing for action after spreading trails.
b. Individual duties in the execution of thecommand PREPARE FOR ACTION are as shownin table I.
Section II. PREPARATIONS FOR TRAVELING
18. TO PREPARE FOR TRAVEL (MARCH ORDER)
a. To prepare to resume travel, the gun beinguncoupled and prepared for action, the commandis: MARCH ORDER. After completion of desig-nated duties personnel take posts as in figure 7.
b. Individual duties in the execution of the com-mand MARCH ORDER are as shown in table II.
23
c. Exceptions modifying MARCH ORDER du-ties are:
(1) If firing is to be resumed shortly inanother position to which the gun mustbe towed by its prime mover, the com-mand MARCH ORDER is not given. Inthis case, at the command for coupling,only such of the operations incident tomarch order are performed as are neces-sary for the movement of the gun andfor the care and security of the equip-ment.
(2) If the command MARCH ORDER isgiven while the gun is coupled, the oper-ations pertaining to march order arecompleted.
19. TO COUPLE
The gun(s) being in position and in marchorder, the command is: COUPLE. The primemover(s), usually under the command of the firstsergeant, approaches the gun and halts in pro-longation of its trails. The procedure for couplingis as follows:
a. The gunner and cannoneers under the direc-tion of the chief of section lower the tail gate;load the tools, ammunition, and equipment; raiseand fasten the tail gate.
24
b. Nos. 2, 3, 6, and 7 hasten to the trail hand-rails, even-numbered on the left, odd-numberedon the right with respect to the tube (fig. 10).
c. Nos. 4 and 5 hasten to the front of the gun.No. 4 releases the left handbrake; No. 5, the right.
d. The chief of section directs the maneuveringof the prime mover until the pintle is almost overthe lunette.
e. After No. 3 has placed the drawbar in travel-ing position, Nos. 2, 3, 6, and 7 raise the trailsand place the lunette in the pintle. No. 2 latchesand locks the pintle.
f. Nos. 4 and 5 assist by placing their weighton the tube.
g. The gunner and No. 1 install the blackoutlight-system. No. 1 secures the blackout light tothe muzzle; the gunner connects the system to theprime mover.
h. The chief of section verifies that the sectionis in order; checking that the handbrakes arereleased, the blackout light-system connected, andthe pintle latched and locked.
i. As each individual completes his duties, hehastens to his post (fig. 6).
_- ·~ r--25'
CHAPTER 5
DUTIES IN FIRING
Section I. INDIRECT LAYING
20. DUTIES OF INDIVIDUALS
The general instructions given in paragraphs 6and 7 on the conduct of section drill apply equallyto section drill in duties in firing. For duties ofthe battery executive see FM 6-140. In general,the duties of individuals in the section in firingare as follows:
a. The chief of section supervises and com-mands his section and is responsible that all dutiesof the section are performed properly, all com-mands executed, and all safety precautions ob-served.
b. The gunner sets the announced deflection,lays for direction, and refers the gun.
c. No. 1 sets the announced site and elevation,operates the breech, and fires the gun.
d. No. 2 loads the gun.e. No. 3 operates the fuze setter and sets the
fuzes.f. No. 4 assists No. 3 in setting fuzes, and
passes the rounds to No. 2 for loading.
26
Sebon
g. No. 5, assisted by Nos. 6 and 7, preparescharges, assembles rounds, and passes the assem-bled rounds to No. 4.
h. Nos. 6 and 7 remove ammunition from thecontainers and assist No. 5 in preparing chargesand assembling rounds. No. 7 keeps empty car-tridge cases out of way of the cannoneers.
i. The driver, after his vehicle is unloaded, isnormally directed to the truck park, designatedby the battery commander, where he remains withhis vehicle and performs maintenance operationsunless assigned other duties by the chief of sec-tion.
21. CHIEF OF SECTION
a. List of Duties.(1) To lay for elevation, assisted by No. 1,
when the gunner's quadrant is used.(2) To measure the elevation.(3) To measure the site to the mask.(4) To indicate to the gunner the aiming
point.(5) To follow fire commands.(6) To indicate when the gun is ready to fire.(7) To give the command to fire.(8) To report mistakes and other unusual
incidents of fire to the executive.(9) To conduct prearranged fires.
(10) To record basic data.
27
5toii&iaftion
(11) To observe and check frequently thefunctioning of the materiel.
(12) To assign duties when firing with re-duced personnel.
(13) To verify the adjustment of the sightingand fire control equipment.
(14) To check, before they are replaced intheir containers, all rounds not firedwhich have been prepared for firing.
b. Detailed Description of Duties.(1) To lay for elevation when gunner's quad-
rant is used.(a) The command QUADRANT (SO
MUCH) indicates that the gunner'squadrant is to be used. In layingfor elevation it is employed onlywhen the range (elevation) quad-rant is inoperative or known to beinaccurate.
(b) An elevation of QUADRANT 361.8,for example, is set on the gunner'squadrant (fig. 14) as follows: Theupper edge of the index plate is setopposite the 360 mark of the gradu-ated arc on the quadrant frame andthe micrometer on the index arm isturned to read 1.8. Care must betaken to use the same side of thequadrant in setting both the indexplate and the micrometer knob.
28 -
Figure 14. Setting the gunner's quadrant.
(c) The announced elevation havingbeen set on the gunner's quadrant,the gun loaded, and the breechblockclosed, the gunner's quadrant is seton the quadrant seat on top of thebreech. The words line of fire mustbe at the bottom of the quadrantand the arrow pointing toward themuzzle. The chief of section mustbe sure to use the arrow whichappears on the same side of thequadrant as the scale which he is
213618°-52-3
29
_ _111 '1Wm ation
using. He stands squarely oppositethe side of the quadrant and holdsit firmly on the quadrant seat, par-allel to the axis of the bore. It isimportant that he take the same posi-tion and hold the quadrant in thesame manner for each subsequentsetting, so that in each case he willview the quadrant bubble from thesame angle.
(d) The chief of section then directsNo. 1 to elevate or depress the gununtil the bubble is centered, beingcareful that the last motion is inthe direction in which it is moredifficult to turn the handwheel. Thechief of section cautions No. 1 whenthe bubble is approaching the cen-ter, in order that the final centeringmay be performed accurately.
(e) Normally, special and calibrationcorrections will be added algebrai-cally at the battery fire directioncenter and simply announced as:NO. (SO-AND-SO), QUADRANT(SO MUCH).
(2) To measure the elevation. At the com-mand MEASURE THE ELEVATION,the gun having been laid, the chief ofsection directs No. 1 to center the cross-
30
n
level bubble, to set the angle of site atscale 300, and with the elevation knob,to center the range quadrant longitudi-nal-level bubble. The chief of sectionthen reads the elevation set on the eleva-tion scale and micrometer and announcesthe elevation thus set as, "No. (so-and-so), elevation (so much)." If the rangequadrant is inoperative or known to beinaccurate, the elevation is measured byplacing the gunner's quadrant on thequadrant seats of the breech ring wherethe chief of section, by raising and low-ering the index arm and turning themicrometer knob, centers the bubble.He then reports the reading on the gun-ner's quadrant to the executive.
(3) To measure site to the mask.(a) The command is: MEASURE THE
MASK. The chief of section has No.1 set site 300 on the angle of sitescale and center the cross-level bub-ble. Then, sighting along the lowestelement of the bore, he directs thegunner and No. 1 to operate thetraversing and elevating mechanismuntil the line of sight just clears thecrest at its highest point in theprobable field of fire. He then directsNo. 1 to center the longitudinal-level
31
C~Mpjirlqation
bubble by turning the elevationknob. The chief of section reads thesite to the mask from the elevationscale and micrometer and reports tothe executive, "No. (so-and-so), site(so much)."
(b) When the executive announces theminimum quadrant elevation or theminimum elevation and site for eachcharge, the chief of section recordsit in a notebook and directs No. 1to chalk the minimum elevation foreach charge to be used on a con-venient place on the shield.
(4) To indicate to gunner the aiming point.When an aiming point has been desig-nated by the executive (FM 6-140), thechief of section will make sure that hehas properly identified the point inquestion. He will then indicate it to thegunner. If there is any possibility ofmisunderstanding, the chief of sectionwill turn the panoramic telescope untilthe horizontal and vertical hairs are onthe point designated.
(5) To follow fire commands. The chief ofsection will follow fire commands. Hewill repeat the commands as required.
(6) To indicate when the gun is ready to fire.When the executive can see arm signals
32
of the chief of section, the chief of sec-tion will extend his right arm verticallyupward as a signal that the gun is readyto fire (fig. 15). He gives the signal assoon as the gunner calls "Ready." Whenarm signals cannot be seen, the chief ofsection reports orally to the executive,"No. (so-and-so) ready."
6
Figure 15. Gun loaded and ready to fire.
(7) To give the command to fire. When No. 1can see arm signals made by the chiefof section, the chief of section will givethe command to fire by dropping hisright arm sharply to his side. When his
a 33
arm signals cannot be seen he commandsorally: NO. (SO-AND-SO) FIRE. Thechief of section will not give the signalor command to fire until all cannoneersare in their proper places. He will re-quire the cannoneers to stand clear ofthe gun until it has been firmly seated.
(8) To report mistakes and other unusualincidents of fire to the executive. If forany reason the gun cannot be fired, thechief of section will promptly report thatfact to the executive, and the reasonstherefor; for example, "No. (so-and-so)out, misfire." Whenever it is discoveredthat the gun has been fired with a mis-take in laying, the chief of section willreport that fact at once; for example,"No. (so-and-so) fired 40 mils right."Whenever the gunner reports that theaiming posts are out of alinement withthe sight, the chief of section will reportthat fact and request permission to re-aline the aiming posts. Likewise, hepromptly reports other unusual incidentsthat affect the service of the gun.
(9) To conduct prearranged fires. Wheneverthe execution of prearranged fires isordered, the chief of section will conductthe fire of his section in conformity withthe prescribed data.
34 -
(10) To record basic data. The chief of sec-tion will record data of a semipermanentnature in a notebook. These include suchdata as minimum elevations; aimingpoints used and their deflections; pre-arranged fires when section data sheetsare not furnished; safety limits in ele-vation and deflection; number of roundsfired, with the date and hour; and cali-bration and special corrections whenappropriate.
(11) To observe and check functioning of themateriel. The chief of section closelyobserves the functioning of all parts ofthe mat6riel during firing. Before thegun is fired, he makes sure that the recoilmechanism contains the proper amountof oil; thereafter he carefully observesthe functioning of the recoil system. Hepromptly reports to the executive anyevidence of malfunctioning (TM 9-325).Correct recoil oil pressure exists whenthe end of the oil index indicator rod isflush with the front face of the recupera-tor cylinder front head. Whenever theamount of reserve oil is less than thatprescribed, the index indicator rod re-cedes into the oil index recess. If the oilreserve pressure is excessive, the oilindex is mechanically unable to indicate
_ 35
Qr~l~ltation
this excess condition due to the construc-tion of the mechanism indicator. Thiscondition necessitates extreme care inestablishing the correct oil reserve.
(12) To assign duties when firing with re-duced personnel. Whenever the personnelof the section serving the gun is reducedin numbers below that indicated in thismanual, the chief of section will makesuch redistribution of duties as will bestfacilitate the service of the gun. Under-strength units, loss of cadremen, casual-ties, and various details will necessitategun section operation with a reducednumber of personnel to the extent thatit is almost normal for cannoneers todouble-up on duties. When round-the-clock firing is to be rendered, cannoneersmust split up and work in shifts so thatprovision can be made for relief. Twopossible sets of duty combinations are:
Section of 5 men. Duties which may becombined
Chief of section andgunner
No. 1 (no other duty)No. 2 and No. 3No. 4 and No. 5No. 6 and No. 7.
36
Section of 4 men. Chief of section andgunner
No. 1 (no other duty)No. 2 and No. 7No. 3, No. 4, No. 5
and No. 6.(13) To verify the adjustment of the sighting
and fire control equipment. See para-graphs 52-64 and TM 9-325 for detailedinstructions on testing and adjustingsighting and fire control equipment.
(14) To check, before they are replaced intheir containers, all rounds not firedwhich have been prepared for firing. Thechief of section personally checks, beforethey are replaced in their containers, allrounds not fired which have been pre-pared for firing, to see that all sevenpowder increments are present in propercondition, that they are assembled in theproper numerical order, and that theyare of the proper lot number. He alsochecks to see that the lot number on theammunition corresponds to the lot num-ber on the container.
22. GUNNER
a. List of Duties.(1) To center the bubbles on the telescope
mount.
37
(2) To lay the gun for direction.(3) To aline the aiming posts with the help
of No. 5.(4) To set a common deflection on a common
aiming point after the gun has been laid.(5) To set or change the deflection.(6) To apply special corrections for deflec-
tion.(7) To refer the gun.(8) To make corrections for aiming post dis-
placement.(9) To call "Ready."
b. Detailed Description of Duties.(1) To center the level bubbles on the pano-
ramic telescope mount. The gunner cen-ters the level bubbles on the telescopemount as part of all operations thatinvolve the use of the panoramic tele-scope except as described below fordirect fire. These bubbles are centeredprior to using the telescope and the levelof the mount is verified before firing((9) below). For direct fire, using thetwo-man, two-sight system (pars. 34-38)the gunner centers the cross-level bub-ble only.
(2) To lay the gun for direction. The gunbeing in position but not laid for direc-tion, the gunner alines the movable azi-muth micrometer (gunner's aid) index
38
S on
ELEVATION KNOBELEVATION INDEXES (FINE)
ROTATING HEAD
ELEVATION ------ OPEN SIGHTRINDEXE SLIPPING AZIMUTH SCALE(COARSE)
DOOR- ----- LOCKING SCREWTHROWOUlT ] 1 AZI MUTH SCALE (NONSUPPING)
LEVER Si~ x1' AZIMUTH SCALE INDEX
NUTLEFT INDEX
SLIPPIN SHUTTERMICROMETER
SCALE .t 't - EYESHIELDAZIMUTH MICROME ER
INDEX (MOVABLE)
Figure 16. Panoramic telescope M12A7-series.
of the sight (fig. 16) with the right(fixed) index. He then loosens the slip-ping azimuth micrometer scale lockingnut (fig. 17) and slips the slipping azi-muth micrometer scale until its zero is
39
aHa
Figure 17. Loosening azimuth micrometer scale
locking nut
alined with the left index (fig. 18). Hetightens the locking nut (fig. 19) andverifies the alinement of zero of the scalewith the left index. He then turns theazimuth micrometer knob to aline zeroof the micrometer scale (and. the leftindex) with the right index. He thenopens the door and with the azimuthmicrometer knob or rotating head setsthe nonslipping azimuth scale at zero(fig. 20). He closes the door over thenonslipping azimuth scale. He then
40 I
Figure 18. Alining the zero of the slipping micrometerwith the left index.
loosens the slipping azimuth scale lock-ing screw and moves the slipping azi-muth scale until its zero coincides withthe index on the outside of the door(fig. 21). He tightens the locking screwand verifies the reading. The executivecommands AIMING POINT THIS IN-STRUMENT, DEFLECTION NO. (SO-AND-SO) (SO MUCH). The gunnersets the deflection for his gun on thepanoramic telescope by disengaging thethrowout lever and turning the rotating
.. _~ . WW41
lation
Figure 19. Tightening the locking nut with slippingazimuth micrometer scale set at zero.
head to the announced hundred milgraduation. He releases the throwoutlever and turns off the last two digitsof the deflection on the azimuth microm-eter scale, using the azimuth micrometerknob. He then traverses the gun untilhis line of sight through the telescopeis on the executive's aiming circle. Hechecks to insure that his bubbles arelevel and announces, "No. (so-and-so)ready for recheck." As additional deflec-tions are announced by the executive he
42
Figure 20. Turning the nonslipping azimuth scale to zero.
sets them on the sight and traverses thegun so that his vertical reticle is on theaiming circle. When the executive an-nounces "No. (so-and-so) is laid" thetube is oriented and should not betraversed except on order of the execu-tive.
(3) To aline aiming posts. The gun havingbeen laid, as in (2) above, the executivemay command, AIMING POINT, AIM-ING POSTS, DEFLECTION 2800, RE-FER. At this command the gunner setsthe panoramic telescope at deflection
43
Sa Ntion
Figure 21. Slipping zero of the slipping aziimvth scaleto index on door.
2800 and, with hand signals, directsNo. 5 in the alinement of the posts withthe vertical reticle of the sight (fig. 22).If because of the nature of the terrainthe posts cannot be set out at deflection2800, the gunner turns the azimuth mi-crometer knob until the slipping azimuthscale is on another even hundred milgraduation. He alines the posts at thisnew deflection. The chief of section re-ports the altered deflection to the execu-tive: "No. (so-and-so) aiming posts at
44
(so many hundred), deflection 2800 inlake (or other reason)." The executivewill then command NO. (SO-AND-SO),DEFLECTION 2800, REFER. At thiscommand the gunner loosens the slippingazimuth scale locking screw and movesthe slipping azimuth scale to deflection2800 (fig. 23). He then tightens thelocking screw and verifies the adjust-ment.
Figure 22. Gunner and No. 5 alining aiming posts.
(4) To set a common deflection on a com-mon aiming point after the gun has beenlaid. The battery having been laid,the ex-
213618°--52 4
P ,,~~~45
i l jiiii -
Figure 23. Common deflection 2800.
ecutive may command, AIMING POINT,CHURCH STEEPLE, REFER. At thiscommand without moving the tubes, the
46
gunners of all guns turn their sights tothe aiming point designated and reportthe deflections to the executive. The ex-ecutive then commands, COMMON DE-FLECTION 2800. At this command eachgunner loosens the locking screw of theslipping azimuth scale and moves thescale until 2800 is in coincidence withthe index on the door. The gunners thenunlock the slipping azimuth micrometerscale locking nut and move the slippingazimuth micrometer scale to zero;tighten the locking nut and verify thatzero is in coincidence with the index andthat line of sight is still on the aimingpoint.
(5) To set or change a deflection. The com-mand is: DEFLECTION (SO MUCH).If, for example, the command is DE-FLECTION 483, the gunner disengagesthe throwout lever with his left thumband turns the rotating head of the sightto 4 (400). He releases the throwoutlever, and with his right hand turns offthe remaining 83 mils on the micrometerscale (fig. 24). He then traverses thegun until the vertical reticle is on theaiming post, being careful that the last.motion is such as to cause the verticalhair of the telescope to approach the
_ 1(C~~~~~ ~47
Figure 24. Deflection 488.
48
Security Information
aiming point from the left to take upany lost motion in the mechanism.
(6) To apply special corrections for deflec-tion. The gunner applies special correc-tions to the announced deflection for hisgun by moving the movable azimuthmicrometer index the proper amount ofdirection. For example, the executiveannounces SPECIAL CORRECTIONS,DEFLECTION 2665, NO. 1 LEFT 10.The gunner on No. 1 gun first sets offthe announced deflection, then movesthe azimuth micrometer index (gunner'said) upward 10 mils. He then resets theannounced, deflection at the index in itsnew position. Subsequent deflections,which are set on the azimuth micrometerscale, will be increased 10 mils auto-matically. The special correction is lefton the gunner's aid until completion ofthe mission or until a new special cor-rection is announced. The new specialcorrection is set off as commanded and isnot applied algebraically by the gunner.
(7) To refer the gun. The command fromthe executive is: AIMING POINT THISINSTRUMENT (OR OTHER POINT),REFER. Without disturbing the layingof the gun the gunner turns only thesight until, with the bubbles level, the
49
-e rn
vertical reticle is on the point desig-nated. He then reports the deflection tothe executive: "No. (so-and-so), deflec-tion (so much)."
(8) To make correction for aiming post dis-placement. For details of correcting foraiming post displacement see paragraph44.
(9j To call "Ready." The gun having beenlaid for direction and No. 1 having called"Set," the gunner verifies the laying,moves his head clear of the telescope,and calls "Ready" to indicate that thegun is ready to be fired.
23. NO. 1
The No. 1 cannoneer is the assistant gunner(par. 4b).
a. List of Duties.(1) To set the site.(2) To apply special corrections for site.(3) To set the elevation.(4) To lay for elevation.(5) To open and close the breech.(6) To call "Set."(7) To fire the gun.(8) To use the rammer.
b. Detailed Description of Duties.(1) To set the site.
(a) When site is to be used, the initial
50
Figure 25. Site 305, elevation 864.
series of fire commands for openingfire will contain the command forsite. The command is, for example,SITE 305 (fig. 25). The site settingis changed only by a new commandSITE (SO MUCH).
(b) To set the site, No. 1 turns theangle of site micrometer knob untilthe announced site is shown. Thesite is indicated by a scale graduatedin hundreds of mils from 0 to 6
_ :Bg-~~~ ·41 e%· ~~51
SeaA. - ion
and a micrometer scale graduatedfrom zero to 100 mils. A site of 300is horizontal. No. 1 first sets theindex in the proper section of thescale in hundreds of mils and thensets the units on the micrometerscale. The last motion in setting thesite should be in the direction ofincreasing site.
(2) To apply special corrections for site.During any mission when special cor-rections for site are announced, the No.1 adds algebraically the site correctionannounced for his gun to each site com-manded. For example, the executiveannounces SPECIAL CORRECTIONS,SITE 310, NO. 1 DOWN 2, NO. 2DOWN 3, etc.; 308 is set on the sitescale of No. 1 gun; 307 is set on the sitescale of No. 2 gun, etc. Special site cor-rections should be marked in chalk onthe right shield.
(3) To set the elevation. To set an elevation,No. 1 sets the site and then sets theannounced elevation on the elevationscale. The elevation is indicated by anelevation scale graduated in hundredsof mils from minus 100 to plus 1200 andan elevation micrometer graduated fromzero to 100 mils. No. 1 grasps the ele-
52 _
vating knob and turns it until theannounced elevation is shown, makingsure that the last movement is in thedirection of increasing elevation.
(4) To lay for elevation. No. 1 turns thecross-leveling worm knob and centersthe cross-level bubble. Having performedthe duties described in (1), (2), and(3) above, he turns the elevating hand-wheel and elevates or depresses the tubeuntil the longitudinal-level bubble is cen-tered making sure that his eye is directlyopposite the bubble and that the lastmovement is in the direction in which itis most difficult to turn the handwheel.
(5) To open and close the breech.(a) To open breech. No. 1 grasps the
breech operating lever handle withhis left hand, depresses the handleto release the catch, and draws ittoward him and to the rear, openingthe breech.
(b) To close the breech. No. 1 graspsthe breech operating handle withhis left hand and pushes it forwardand away from him until the breechis closed and the latch is engaged.When the breech is fully closed thelatch is automatically engaged.
(6) To call "set." No. 1 calls "Set" when the
53
gun has been loaded, the breech closed,and the gun laid for elevation.
(7) To fire the gun. At the chief of section'ssignal or command, NO. (SO-AND-SO)FIRE (par. 21b(7)) No. 1 grasps thehandle of the lanyard with his righthand and pulls (fig. 26). After firing,release the lanyard. In case of a misfire,the instructions contained in paragraph85 will be followed.
(8) To use the rammer. Normally the ram-mer components will be handled by No.
4
Figure 26. No. 1 firing gun.
54
1. The rammer staff is used to extractcartridge cases which cannot be ejectedby the extractor. To extract a cartridgecase, No. 1 inserts the rammer staff inthe bore, and lightly taps the bottom ofthe inside of the case until it is loosenedand can be pushed out of the chamber(fig. 27). No. 2, standing at the breech,receives the cartridge case in both
·. 2
Figure 27. Using rammer to remove stuck cartridge case.
hands. To extract an unfired round, theprocedure described in paragraph 49 willbe followed.
55
S~agj~i ation
24. NO. 2
a. List of Duties.
(1) To load the gun.
(2) In volley fire, to call out the number ofthe round and the announced elevation.
(3) To assist No. 6 in shifting the left trailwhen necessary.
(4) When the breech is opened, to inspectthe chamber and bore to insure that theyare clear.
Figure 28. No. 2 receiving round from No. 4.
56
Secu rl. on
b. Detailed Description of Duties.(1) To load the gun. To receive the round,
No. 2 steps with his left foot towardNo. 4 and grasps the round with hisright hand at the base of the cartridgecase and his left hand in front of therotating band (fig. 28). After resuminghis position facing the gunner, and afteran elevation or quadrant has been an-nounced, he inserts the round in thebreech and pushes it home with his rightfist (fig. 29). It is extremely importantthat he use his fist to guard againstgetting his fingers crushed by the closingbreechblock. No. 2 will be particularlycareful to avoid striking the fuze againstany portion of the gun. A round to beloaded will be held well out of the pathof recoil until the gun is again in bat-tery.
(2) To call out the number of the round andthe announced elevation in volley fire.In volley fire, to insure firing the correctnumber of rounds, No. 2 calls out thenumber of the round and the elevationas he finishes loading the projectile. Ashe finishes loading the last round, headds, "Last round." For example, whentwo rounds are to be fired at elevation480, he calls out, "Second and last round,
57
'-itV..inion
Figure 29. Loading the gun.
480." He should not speak louder thanis necessary to insure his being heard bythe members of his own section.
(3) To assist No. 6 in shifting the left trailwhen necessary. No. 2 assists No. 6 inshifting the left trail as directed by
the gunner. The command is: MUZZLERIGHT (LEFT), and the trail is shiftedin the opposite direction so that the muz-zle is swung in the direction commanded.At the gunner's command or signal tostop shifting, Nos. 2 and 6 lower thetrail to the ground.
(4) When the breech is opened, to inspect thechamber and bore to insure that theyare clear. No. 2 will inspect the chamberand bore after each round is fired tomake certain that the chamber is clearand that the bore is free of any residuefrom the charge. He calls out "boreclear" if it is clear.
25. NO. 3
a. List of Duties(1) To fuze or change fuzes of projectiles.(2) To set the fuze setter.(3) To set fuzes.(4) To apply special corrections for his gun
to fuze settings.(5) To assist No. 5 in assembling rounds
when necessary.(6) To assist No. 7 in shifting the right trail
when necessary.b. Detailed Description of Duties.
(1) To fuze or change fuzes of projectiles.No. 3 removes the fuze or closing plug
59
faon
from the projectile; removes (or re-places) the supplemental charge, if nec-essary; and screws in the designatedfuze. In assembling fuzes to or disassem-bling fuzes from shell, only the author-ized fuze wrench should be used. VT fuzesshould be screwed in by hand and tight-ened with fuze wrench M18 using onlymanual force. Do not hammer on thewrench or use an extension handle. Ifa time fuze is used No. 3 removes thesafety pull wire from the fuze and, if abooster is present, the safety pin from
CORRECTOR SCALE CLAMPINGSCREW
TIMESCALE
Figure S0. Setting the fuze setter.
60
the booster. Boosters without safety pinswill not be used.
(2) To set the fuze setter M22 or M23. Thecorrector scale is not used. No. 3 makescertain that the corrector scale is lockedat corrector setting 30. He releases thetime scale clamping screw marked "T"and grasping the handle, turns the bodyuntil the index on the body is oppositethe announced time on the time scale(fig. 30). He then locks the time scale
clamping screw, being careful not to dis-turb the setting. For accuracy, No. 3looks squarely at the scales and indexesin the same manner each time.
(3) To set fuzes.(a) Selective superquick and delay fuzes.
When FUZE QUICK is announced,No. 3 will verify the superquicksetting. (The slot on the settingsleeve should be alined with the let-ters SQ.) When FUZE DELAY isannounced, he will turn the settingsleeve until the slot is alined withthe word delay.
(b) Combination time and superquickfuzes. These fuzes may be set fortime action. However, the percus-sion element will detonate the roundupon impact if the time element
213618--52-5
61
-Bim'd-ha on
fails. After fuzing the projectile,No. 3 removes the safety pull wirefrom the fuze. For percussion actionthe command is FUZE QUICK M500(or other designation). For timefuzes No. 3 verifies that the S onthe setting ring is alined with theindex on the fixed ring. If not, hesets it at S.
(c) VT fuzes. These fuzes operate andfunction in such a manner as to re-quire no setting on the part of anypersonnel.
(d) Setting time fuzes.1. Using fuze setter M22 or M23.
After making the announced set-tings on the fuze setter M22 orM23, No. 3 carefully places itover the fuze and turns the setterclockwise until the notch on thetime ring of the fuze engages thestop on the setting ring of thefuze setter. He places the handlein the most convenient position,pushes down on the fuze setteruntil the notch fully engages thestop, and continues to turn itclockwise until the pawl in the ad-justing ring assembly drops intothe notch of the fixed fuze ring
62.
(fig. 31). This prevents furtherturning and indicates that thefuze is set. He then lifts the fuzesetter from the fuze and makesa visual check of the fuze settingto insure that the fuze ring notchwas actually engaged and that thefuze is properly set. If the desiredtime setting is passed, the timering on the fuze should be turnedback several seconds and thencontinued in the original direc-
Figure 31. Setting time fuze.
63
Siion
tion until the desired time isagain opposite the index.
2. Using fuze setter M14. This is awrench-type fuze setter in whichthe fuze time scale is used in set-ting the fuze. With M500 fuzesNo. 3 engages the key of thiswrench-type fuze setter in thenotch on the setting ring of thefuze and rotates the setting ringclockwise (increasing direction)until the announced time settingof the fuze time scale is oppositethe index mark on the fuze. WithM54 and M55 fuzes, the settingring is rotated in a counterclock-wise direction.
(4) To apply special corrections for his gunto fuze settings. When special correc-tions are announced for his gun, No. 3will apply the special fuze setting cor-rection; for example, the command isTIME 18.2, NO. 1 PLUS .7, the No. 3cannoneer on No. 1 gun must add .7 ofa second to 18.2 and to all subsequentcommands received for fuze time inthat mission or until a new special cor-rection is received for his gun.
(5) To assist No. 5 in assembling rounds,when necessary. When directed by the
64
chief of section, No. 3 assists No. 5 infitting the projectile to the cartridge caseafter the charge has been prepared.
(6) When necessary, to assist No. 7 in shift-ing right trail. No. 3 assists No. 7 inshifting the right trail as directed bythe gunner. The command is: MUZZLERIGHT (LEFT), and the trail is shiftedin the opposite direction so that the muz-zle is swung in the direction commanded.At the gunner's command or signal tostop shifting, Nos. 3 and 7 lower the trailto the ground.
26. NO. 4
a. List of Duties.(1) To assist No. 3 in setting time fuzes.(2) To pass the round to No. 2.
b. Detailed Description of Duties.(1) To assist No. 3 in setting time fuzes.
See paragraph 25b(3) for details ofsetting time fuzes.
(2) To pass the round to No. 2. No. 4, withhis left hand under the cartridge case,his right hand under the projectile,taking care that the projectile and car-tridge case do not separate, passes theround to No. 2 in a manner that enablesNo. 2 to grasp the base of the cartridgecase in his right hand (fig. 28).
65
-JOIIIHpi d on
27. NO. 5
a. List of Duties.(1) To set out and to assist the gunner in
alining the aiming posts.
(2) To prepare charges.(3) To replace increments in the cartridge
case before rounds are replaced in theircontainers.
b. Detailed Description of Duties.
(1) To set out aiming posts. When so di-rected by the chief of section, No. 5 sets
out the aiming posts under the guidanceof the gunner (par. 22b(3)).
(2) To prepare charges. The fire commandsfor opening fire will include the designa-tion of the charge. No. 5 verifies thenumber of increments and removes thoseincrements numbered higher than thecharge designated (fig. 32). He then re-places the remaining increments in thecartridge case in their original numeri-cal order. After No. 5 has prepared thecharge he fits the projectile to the car-tridge case assisted by No. 3, whennecessary. Care is taken to prevent dam-age to the lip of the cartridge case. Whenso directed, Nos. 6 and 7 assist No. 5.
(3) To replace increments in cartridge casebefore rounds are replaced in their con-
66 ._
Figure 32. Preparing ammunition.
tainers. Under the personal supervisionof the chief of section, No. 5, assistedby Nos. 6 and 7, replaces incrementsin cartridge cases for all ammunitionprepared for firing but not fired. Hecarefully checks to see that all sevenincrements are present, in the propercondition, assembled in the proper nu-merical order, and that they are of theproper lot number.
28. NO. 6
a. List of Duties.(1) To remove ammunition from containers.
67
(2) To assist No. 5 in preparing charges.(3) When necessary, assisted by No. 2, to
shift the left trail.(4) To replace unused ammunition in con-
tainers.b. Detailed Description of Duties.
(1) To remove ammunition from containers.Assisted by No. 7, No. 6 removes roundsfrom their containers and arranges themso that they are within easy reach ofNo. 5. He inspects each round to see thatit is free from sand and dirt and thatthe rotating band is not burred. With acloth, he wipes off any foreign matter.Projectiles with burred rotating bandsare put aside until he can remove theburrs with a file.
(2) To assist No. 5 in preparing charges.When so directed, Nos. 6 and 7 assistNo. 5 in preparing charges as describedin paragraph 27b(2).
(3) When necessary, assisted by No. 2, toshift the left trail. When so directed bythe gunner, No. 6, assisted by No. 2,shifts the left trail (par. 24b (3)).
(4) To replace unused ammunition in con-tainers. Under the personal supervisionof the chief of section and assisted byNo. 7, No. 6 replaces unused ammunitionin containers, being careful that the lot
68
number on the ammunition correspondsto the lot number on the container.
29. NO. 7
a. List of Duties.(1) To assist No. 6 in removing ammunition
from containers.(2) To assist No. 5 in preparing charges.(3) To keep empty cartridge cases out of the
way of the cannoneers.(4) When necessary, assisted by No. 3, to
shift the right trail.(5) To assist No. 6 in replacing ammunition
in containers (par. 28b (4)).(6) Lays or picks up telephone wire to execu-
tive's control station as directed.b. Detailed Description of Duties.
(1) To assist No. 6 in removing ammunitionfrom containers. No. 7 assists No. 6 inremoving rounds from their containersas described in paragraph 28b (1).
(2) To assist No. 5 in preparing charges.When so directed Nos. 7 and 6 assistNo. 5 in preparing charges as describedin paragraph 27b(2).
(3) To keep empty cartridge cases out ofway of cannoneers. No. 7 places theempty cartridge cases in rear of theright trail where they will be out of theway of the cannoneers.
69
Se Mllymrvon
(4) When necessary, assisted by No. 3, toshift the right trail. When so directedby the gunner, No. 7, assisted by No. 3,shifts the right trail (par. 25b(6)).
(5) To assist No. 6 in replacing ammunitionin containers. No. 7 assists No. 6 inreplacing rounds in containers in themanner described in paragraph 28b(4).
(6) Lays or picks up telephone wire to execu-tive's control station as directed.
Section II. DIRECT LAYING, GENERAL
30. GENERAL
a. Firing by direct laying is a special techniquethat demands a high standard of training. Thesection must operate as an independent unit.Training in direct laying is based on the tech-nique employed in indirect laying. Enemy targetstaken under fire by the section in direct layingare usually those capable of returning fire on thegun section at point-blank range, therefore, thespeed and accuracy required in indirect layingbecomes even more important for direct layingmissions.
b. There are two basic systems of direct layingfor use with the 105-mm howitzer: The two-man,two-sight system (pars. 34 to 38, incl.) where thegunner, using the panoramic telescope, lays for
70
E; i ! al
Figure 33. Serving the gun, direct laying, two-man,two-sight system.
direction, and No. 1, using the elbow telescope,lays for range (fig. 33); and the one-man, one-sight system (pars. 39 to 42) where the gunnerlays for both direction and range using the pano-ramic telescope.
c. The chief of section will designate the systemof laying to be used when firing by direct firemethods. Selection of the system is dependentupon the type which can more effectively engagethe target. Training must include both systemsof direct laying.
71
d. For additional information on direct layingsee FM 6-140.
31. PREPARATION OF A RANGE CARD
a. The chief of section is responsible for de-fense in his assigned sector, but he should beprepared to fire on targets in other sectors.
HILL
HILL TREEtR o E/
0am~~O H OUSE
ORCHARD
% BARN /? HILL
Figure 34. Range card for direct laying.
b. As soon as possible after occupation of posi-tion, the chief of section measures or estimatesthe ranges to critical points in likely avenues ofapproach for enemy tanks and vehicles, and pre-
72
pares a range card (fig. 34) upon which he notesthe ranges for quick reference.
c. If there are no prominent terrain features,stakes may be driven into the ground at criticalpoints for reference. As time permits, the rangecard will be improved by replacing estimatedranges with more accurate ranges obtained byfiring, pacing, taping, vehicle speedometer read-ing, map measurement, or survey.
32. FIELD OF FIRE
The sector of fire for the gun should, if possible,be cleared of all obstructions that might endangerbattery personnel when the gun is fired, or thatmight hinder observation. Care should be takennot to give away the location of the position.
33. CONDUCT OF FIRE
a. Trajectories. Trajectory characteristicschange with the type of ammunition and thecharge fired. The following trajectory character-istics govern the conduct of fire:
(1) Ranges from 0 to 400 yards using HEATor ranges from 0 to 600 yards using HEcharge 7. Within these range limits, thetrajectory will be flat enough to preventan 8-foot tank from passing safely underit. Fields of fire and terrain allowing,the upper range limits for the ammuni-
73
tion and charge used are the ideal atwhich to open fire. Fire can then be con-ducted over the maximum time with-out misses if deflection is correct. Alsothere is less risk of obscuring the targetwith the smoke from a short burst.
(2) Ranges from 400 to 700 yards usingHEAT or 600 to 1000 yards using HEcharge 7. These range limits include thezone in which the trajectory is suffi-ciently flat to permit direct estimationof range without actually bracketing thetarget. Assuming little dispersion, if ahit is obtained at the bottom of an 8-foottank firing at the upper range limit, 700yards for example, with HEAT, the add-ing of a 100-yard range change willresult in a round which will just brushthe top of the tank. During adjustmentwithin this zone, range changes shouldseldom be more than 100 yards, and fre-quently range changes of 50 yards willbe sufficient. The upper limits mentionedherein are the greatest ranges at whichfire should be opened unless tactical con-ditions require otherwise. A trained guncrew should obtain hits by the secondshot.
(3) Ranges from 700 to 1300 yards usingHEAT or 1000 to 1800 yards using HE
74
charge 7. This zone includes the rangesat which hits are only reasonably pos-sible. Bracket methods are normallyused to obtain adjustment in this zone.There is more dispersion in this zone;fire should not be opened at these rangesunless surprise is not important.
(4) Ranges over 1300 yards using HEAT orover 1800 yards using HE charge 7. Atranges over 1300 yards using HEAT orover 1800 yards using HE charge 7,direct laying is not advisable againstmoving targets. Dispersion is the con-trolling factor. Ranges must be knownaccurately or determined by bracketing.At these ranges the slope of fall of theprojectile becomes so great that a hiton a moving target is very difficult toobtain.
b. V/ertical Displacement Table. Vertical dis-placement is the change in the point of burst (upor down) between two rounds fired at an uprighttarget at different range settings. The followingtable shows the vertical displacement for a 100-yard range change at various ranges, firing shellHEAT and shell HE charge 7. The use of verticaldisplacement in direct firing is explained inFM 6-140.
75
Table III
Vertical Displacement (feet) per 100 Yd. Range Change
Displace- Displace-Range ment, feet, Remarks ment, feet, Range(yards) Shell Shell HE, (yards)
HEAT Charge 7
100 1 Start firing using 400 yard .5 100200 2 range setting. 1.5 200300 3 2 300
2.5 4003.5 500
400 4 Start firing with estimated 4 600500 5.5 range. Increase or de- 5 700600 6 crease by multiple of 50 or 5.5 800700 8 100 yards. Bracketing rot 6 900
necessary. 7 1,000
800 9 Bracket target (get bursts 8 1,100900 10.5 over and short) to obtain 9 1,200
1,000 11.5 hit. 10 1,3001,100 13 10.5 1,4001,200 14.5 ' 11.5 1,5001,300 16 13 1,600
14 1,70014.5 1,800
Over At ranges over 130o yards Over1,300 using HEAT or over 1800 1,800
yards using HE charge 7,direct firing is too inaccu-rate to be used againstmoving targets (a(4)above).
Note.-Information computed from data obtained from FT 105-H-4.
76 1
c. Types and Selection of Targets for DirectLaying. Targets for direct laying usually consistof hostile vehicles, tanks, and personnel threaten-ing the battery. Enemy personnel, whether aloneor accompanying tanks, will seldom presentthemselves as a clearly defined target. Normally,attacking infantry, using all available cover,reveal themselves only fleetingly. Accordingly fireis conducted on the area containing the attackersrather than upon the individuals. Tanks usuallyattack in groups and may be accompanied byinfantry. Normally, first priority is given toattack of those targets within the assigned sectorof the weapon and second to targets in othersectors. Priority within the assigned zone is givento:
(1) Tanks at short ranges, threatening tooverrun the position.
(2) Hull down stationary tanks, covering theadvance of other tanks.
d. Ammunition and Fuzes.(1) General. For close-in fires a variety of
fuzes and shells are available. Whenusing high explosive shell, charge 7 isused habitually for speed, ease in adjust-ment, imparting forward motion to frag-ments, and more effective fuze action.The flat trajectory resulting from use ofcharge 7 coupled with dug-in guns maymake extremely close-in fire impossible
213618°-52-6
77
due to projectiles skipping without de-tonating on impact. At ranges of 200to 400 yards fuzes may fail to functionon hard, flat ground; however, prepara-tion of sectors of fire will remedy thissituation. The terrain may be preparedfor direct fire by placing mounds ofsandbags, dirt, or logs in the gun's sec-tor of responsibility. When direct fireis placed on these or other previouslyselected points, as they are approachedby an attacking force, the necessity foradjusting fire is reduced.
(2) Ammunition. Ammunition may be HE,HEAT, or white phosphorus (WP).HEAT is designed for, and is highlyeffective in, antitank and antivehiclefires. HE is ideally suited for anti-personnel fire and is effective againstvehicles and tanks. WP may be used toset immobile tanks and vehicles on fire,to further restrict defiles, and to producecasualties. However, consideration mustbe given to the effect on the defense ofthe resulting smoke screen.
(3) Fuzes. Base detonating fuzes are con-tained in HEAT projectiles. WP ammu-nition is fuzed with a superquick-delayfuze while HE may be used with fuzesquick, delay, or time.
78
(a) Fuze quick is the most desirablefuze to use with HE shell on close-infires. It is highly effective and, sinceno fuze setting is required, is muchfaster to use.
(b) The time required to set the fuzeand to adjust the point of impactfor maximum ricochet effect makesfuze delay less desirable than fuzequick. When using fuze delay togain ricochet effect, the point of im-pact is adjusted 10-30 yards in frontof the target. If less than 50 percent of the bursts are ricochet, thefuze should be changed to quick.
(c) Fuze time is the least desirable typefuze for close-in fires. Due to thewide range dispersion resultingfrom variations in time of burningwith short fuze settings, this fuzeshould be used only for ranges ofmore than 1,000 yards. The areascovered effectively by air and rico-chet bursts are similar.
~s-79_li~ · 79
SeCtion
Section III. DIRECT LAYING, TWO-MAN,TWO-SIGHT SYSTEM
34. CHIEF OF SECTION
a. List oj Duties.(1) To conduct the fire of his gun.
(2) To identify or select the target.
(3) To estimate the range to the target.
(4) To determine the lead. in mils.
(5) To give initial commands.
(6) To give subsequent commands, based
upon observed effect.
b. Detailed Description of Duties.
(1) To conduct the fire of his gun. The chief
of section conducts the fire of his gun
when the executive commands: TAR-
GET (IDENTIFICATION), FIRE AT
WILL, or simply FIRE AT WILL.
(2) To identify or select the target. If the
executive designates an object or one of
a group of objects as the target, the
chief of section must correctly identify
this target. If the target is a group of
tanks or other objects, the chief of sec-
tion selects the target that, in his estima-
tion, is the greatest threat to his own
position or the position of the supported
troops.(3) To estimate the range to the target. A
range card (fig. 34) with ranges to key
80
points provides the best means for deter-mining the initial range. If a range cardhas not been prepared the range is esti-mated.
(4) To determine the lead in mils. Theamount of lead in mils is determined bythe speed of the target, range, course atwhich it is moving, and charge beingfired. Approximate initial leads are:With shell HEAT-slow (0-5 mph), 5mils; medium (5-10 mph), 10 mils; fast(10-15 mph), 15 mils. Based upon theobserved effect, the lead is changed asnecessary.
(5) To give initial command. The chief ofsection will give fire commands contain-ing the following elements in sequences:(a) Designation of target. The command
is: TARGET (SO-AND-SO).(b) Projectile, charge and fuze. The
commands specify the appropriateitems in sequence, such as: SHELLHE, CHARGE 7; or SHELL ANTI-TANK. With shell HEAT, no com-mand for charge or fuze is necessarybecause these are not variable butare fixed.
(c) Lead. The command is: LEAD (SOMUCH). See (4) above for esti-mating initial leads.
81
(d) Method of fire. Fire is continuousunless otherwise commanded. Incontinuous fire the gun is loadedand laid as rapidly as possible andfired at the command of the gunner.
(e) Range. The command is: RANGE(SO MUCH). The range com-manded by the chief of section is
that range to be set on the elbowtelescope sight reticle. When firingcharges other than those for which
the reticle of the sight is graduated,the chief of section converts hisestimated range to an appropriaterange command for the charge andtelescope being used. For examplewhen firing shell HE, charge 7,using the elbow telescope graduatedfor shell HEAT, for a range esti-mated as 800 yards the commandis RANGE 500. A conversion tablefor various charges may be pre-pared using data obtained from thefiring tables for the weapon.
(6) To give subsequent commands, based on
observed effect.(a) Change in lead. During adjustment
the lead is changed by the command
RIGHT (LEFT) (SO MUCH).(b) Change in range. During adjust-
82
ment the range is increased by thecommand ADD (SO MUCH) anddecreased by the command DROP(SO MUCH). See paragraph 33 for
determining range changes duringadjustment of fire.
35. GUNNER
a. List of Duties.(1) To center the cross-level bubble on the
panoramic telescope mount.(2) To set the elevation indexes and the azi-
muth scales of the panoramic telescopeat zero.
(3) To lay on the target with the announcedlead.
(4) To track the target.(5) To command FIRE.(6) To follow subsequent commands.
b. Detailed Description of Certain Duties.(1) To lay on the target with the announced
lead and track the target.(a) Prior to any direct fire mission the
gunner verifies that the movableazimuth micrometer (gunner's aid)index is set at zero.
(b) If the slipping azimuth and slippingmicrometer scales have not beenslipped, the gunner zeros these twoscales.
83
(c) If only the slipping azimuth scalehas been slipped, the gunner disre-gards this scale. He opens the doorover the nonslipping azimuth scale
and sets that scale at zero. Themicrometer scale is brought to zero.
(d) If both the slipping micrometer scaleand the slipping azimuth scale have
been slipped, the gunner opens theazimuth scale door and turns thenonslipping azimuth scale to zero.
He then turns the azimuth microm-eter knob until the left index of themicrometer matches the right index.
(e) The operations described in (a),
(b), (c), and (d) above make theline of sight of the telescope parallelto the axis of the bore. The gunnerthen tracks the target using thetraversing handwheel to keep theappropriate vertical grid line in thereticle of the telescope ahead of thetarget. The announced lead is meas-
ured on the horizontal reticle scale(fig. 35). In the two-man, two-sightsystem the vertical location (range)of the target is controlled by No. 1.If time does not permit the chief of
section to announce the lead, it isestimated by the gunner.
84
40 30 20 10 10 20 30 40
I0 I0
Figure 35. Gunner's sight picture, two-man, two-sightsystem (lead 15 mils).
(2) To command FIRE. After No. 1 hascalled "Set" and when ready, thegunner commands FIRE.
36. NO. 1
a. List of Duties.(1) To lay for range, using the elbow tele-
scope.
85
r-- -b
(2) To track the target.(3) To call "Set" when the gun is loaded
and the correct range line is on the cen-ter of the visible mass of the target.
(4) To follow subsequent commands.b. Detailed Description of Certain Duties. In
direct laying, using the elbow telescope, the No. 1sets off the range commanded by the chief of
105mm HowH.E.A.T., M67
N- -N2- -24- -4
[6~- -68- -810- -10
Figure 36. o. ight icture, elbow telescope D,
Figure 36. No. 1's two-sight picture, elbow telescope M16ATD,two-man, two-sight system (range 600 yards HEAT).
86
section by placing the appropriate range line inthe reticle of the elbow telescope on the center ofthe visible mass of the target; he tracks the targetwith the elevating handwheel maintaining theproper range line on the center of the target(fig. 36).
37. NO. 5
a. List of Duties.(1) To open and close the breech..(2) To indicate that the gun is loaded by
tapping No. 1 on the shoulder.(3) To fire the gun at the gunner's command.
b. Detailed Description of Certain Duties. No. 5will take position in rear of No. 1 and will openand close the breech and fire the gun. He tapsNo. 1 with his right hand; pulls the lanyard withhis left hand.
38. REMAINDER OF SECTION
The remaining cannoneers perform their dutiesas prescribed for indirect laying.
Section IV. DIRECT LAYING, ONE-MAN,ONE-SIGHT SYSTEM
39. CHIEF OF SECTION
The duties of the chief of section are the sameas in the two-man, two-sight system (par. 34).
i n_ _ 8 7~- 1 87
40. GUNNER
a. List of Duties.(1) To match the elevation indexes of the
panoramic telescope mount and set theazimuth scales of the sight at zero (par.35a and b(1)).
(2) To center the cross-level bubbles on thepanoramic telescope mount.
(3) To lay on the target with the announcedlead and range.
(4) To track the target.(5) To command FIRE.(6) To follow subsequent commands.
b. Detailed Description of Certain Duties.
(1) The gunner matches the sight mountelevation indexes on the actuating armand rocker and those on the elevationknob and shaft. He then sets the eleva-tion indexes and azimuth scales of thepanoramic telescope at zero. Action inregard to slipping scales is as describedin paragraph 35b(1). After laying ap-proximately on the target, he centers thetelescope mount cross-level bubble. Hethen lays on the target with the an-nounced lead and range measured on thescales of the reticle (fig. 37). Otherduties are performed as in the two-man,two-sight system (par. 35).
88
CHARGE 7
4302010 1020 30 40
Figure 37. Gunner's sight picture, one-man, one-sightsystem (lead 15 mils; range 600 yards).
(2) The reticle of the panoramic telescopeis graduated for ranges correspondingto shell HE charge 5, and is so marked.At short ranges (under 2400 yards) theelevations for charge 7, are almostexactly half those of charge 5. Hencethe reticle can be used for charge 7 by
89
~ 0~o~ n
laying with half the true range. Whenfiring shell HEAT, the correct range set-ing is determined and announced by thechief of section (par. 34b (5) (e)).
41. NO. 1
The duties of No. 1 when using the one-man,one-sight system are to open and close the breech,to call "Set" when the gun is loaded, and to firethe gun at the gunner's command FIRE.
42. REMAINDER OF THE SECTION
The remaining cannoneers perform their dutiesas prescribed for indirect laying.
90
CHAPTER 6
TECHNIQUES AND SITUATIONS THAT REQUIRESPECIAL ATTENTION
43. PRECISION IN LAYING
a. Sighting and laying instruments, fuze set-ters, and elevating and traversing mechanismsmust be properly operated to reduce the effectsof lost motion. This requires that the last motionin setting instruments and in laying be in thedirection prescribed in this manual. To insureaccurate laying, personnel who have duties inconnection with laying the gun must be requiredto verify the laying after the breech has beenclosed.
b. The line of sight when setting and readinga scale or centering a bubble should be at a rightangle to the scale or level vial to prevent parallaxerrors. Bubbles should be centered exactly.
c. For uniformity and accuracy in laying onaiming posts, the vertical hair in the reticle of thepanoramic telescope should be alined with the leftedge of the aiming posts.
91
44. AIMING POINTS AND DISPLACEMENTCORRECTIONS
a. General. After the gun has been laid initiallyfor direction it is referred to the aiming postsand usually to one or more distant aiming pointsas described in paragraph 22b(2) and (3). Anaiming point must have a sharply defined pointor vertical line clearly visible from the gun sothat the vertical hair of the panoramic telescopecan be alined on exactly the same place each timethe gun is re-laid.
b. Distant Aiming Point. A distant aimingpoint is one at sufficient distance so that normaldisplacements of the gun in firing or traverse willnot cause a horizontal angular change in direction(with the same settings on the azimuth scales)of more than one-half mil. The executive officerusually designates any distant aiming point orpoints to be used.
c. Aiming Posts.(1) Two aiming posts are used for each gun.
Each post is equipped with a light foruse at night. The most desirable distancefrom the gun to the far aiming post,considering accuracy of laying, visibility,and ability to control the aiming postlights, is 100 yards. The near post isset up at the mid-point between the farpost and the gun and is lined in by the
92
gunner so that the vertical hair of thetelescope and the two aiming posts arein alinement. To insure equal spacing ofaiming posts, the distance to both thenear and the far post should be pacedby the same man. Where ground condi-tions make pacing inaccurate, the dis-tance from the gun to the posts may bemeasured using the panoramic telescope,with the aiming post as a stadia rod.((4) below).
(2) For night use, the aiming post lightsshould be adjusted so that the far onewill appear several feet above the nearone. The two lights placed in this waywill establish a vertical line for layingthe gun.
(3) Since the panoramic telescope is mountedat considerable distance from the centerof rotation of the top carriage, largechanges in deflection will cause misaline-ment of the aiming posts. Placing theaiming posts to the left front at a deflec-tion of approximately 2800 when the gunis in center of traverse will keep thismisalinement to a minimum and stillallow for maximum visibility (d below).
(4) To measure the distance from gun toaiming posts the stadia method may beemployed, using the panoramic telescope
213618 °-52--7
93
= li onlI|jP t
and the aiming post as measuring de-vices. No. 5 cannoneer, when setting outthe aiming posts, holds the upper sectionof one of the aiming posts in a horizon-tal position, perpendicular to the line ofsighting. The gunner measures the lengthof this section in mils on the reticle ofthe panoramic telescope. For example,the upper section of the aiming post is41/2 feet long, so that it measures 15 milswhen it is 100 yards from the gun. Theproper location for the near post, in thiscase, would be at the point at which the41/2-foot section measures 30 mils. Inmany cases, the ideal spacing of 50 and100 yards cannot be obtained but theposts will be properly spaced when thenear post is set at a point where the41/2-foot section measures twice the num-ber of mils it measured at the far postlocation. This measurement may be per-formed at night by attaching the nightlighting devices at the 41/2-foot markson the aiming posts.
d. Correction for Displacement of AimingPosts. When the gunner notes that the verticalhair of the telescope is displaced from the lineformed by the two aiming posts (or aiming postlights), he lays the gun in such a manner thatthe far aiming post (light) appears exactly mid-
94
FAR POT FAR POST
NEAR POST NEAR POST
-
LEFT RIGHTDISPLACEMENT DISPLACEMENT
Figure 38. Gunner's sight picture of aiming posts inproper relationship when correcting for displacement.
way between the near aiming post (light) and thevertical hair (fig. 38). If the displacement is dueto traversing the gun, the gunner continues tolay as described above. If the displacement is dueto progressive shifting of the carriage from shockof firing or other cause, the gunner will notifythe chief of section, who, at the first lull in firing,will notify the executive and request permissionto realine the aiming posts. To realine, the gunis laid with the far post midway between thenear post and the vertical hair (fig. 38). The faraiming post is moved into alinement with thevertical hair of the telescope and then the nearaiming post is alined. If terrain conditions make
95
PROPOSITION:The new line of sightDC, is parallel to theline of aiming posts, PBwhen the sight pictureis such that the far aiming post (B) appearsexactly midway between the near aiming ANGLEANGLE(A)and the vertical hair (b). BD C
GIVEN: ' 0 a Io
I. The aiming posts are initially positionedand aligned correctly. (The near post at themid-point between the for post and the gun.The vertical hair of the telescope and thetwo aiming posts in alignment.) ! !.I2. The gun (and sight) is displacedarom its iinitial position. This displacement, ODP isassumed as small compared to the distncefrom the gun to the near aiming post (PA).Therefore the distance iPA.j assumed tobe equal to the distance DA. C B3. The sight is positioned so that 4BDCO-4ADBO FAR
AIMINGTO PROVE: POST
That line CD is parallel to line Pg. z
PROOF: FPA-AB By initial placement of
aiming posts.PA-DA By initial assumption. z
. -.. D"A=B Things equal to the something are equal to each other.
. ADB is an An isosceles triangle is a tri- Aisosceles triangle. angle two of whose sides are NEAR
equal. I AIMING· ADBOB= zABDO The base angles of an isosceles POST
triangle are equal.
4AODB=<,:BDCO By measurement in the sight.
,'.:ABDe=4BDCO Things equal to the samething are equal to each other.
S PB | DC If two straight lines are cutby o third straight line, andthe alternate-interior anglesso formed are equal,then thetwo straight lines are parallel. , R
Q.E.D. POSITION- DISPLACED
POSITION
Figutre 39. Mathematical explanation of aiming post
displacement correction.
96
it impracticable to move one of the two aimingposts, the gun is laid for direction and referredto the aiming post which cannot be moved. Thisdeflection is reported to the executive. The otherpost is alined using the method described in para-graph 22b(3) and the azimuth micrometer scaleis slipped to retain the same deflection that wasused prior to realinement of the aiming posts.The explanation of aiming post displacement cor-rection is shown in figure 39.
45. PREPARATION OF POSITION FOR EMPLACEMENTOF GUN
a. General. For detailed information on thepreparation of the gun position see FM 5-15 andand FM 6-140. The gun should be emplaced onlevel ground to insure stability in firing and toreduce the time needed for leveling the telescopesand range quadrant.
b. Spade Pits. Unless lack of time prevents,pits should be dug for the spades. On soft groundthe spades can be seated by firing, but the dis-placement of the carriage will be greater than ifthe spades had been dug-in initially.
c. Recoil Pits. A recoil pit with a full 50-inchclearance between the breech and the ground mustbe dug for high-angle fire. After the gun has beenemplaced and, if possible, seated, the gun will beelevated to maximum elevation, and a recoil pitdug that will insure proper clearance throughout
97
'.ga rtion
the limits of traverse. When not firing high-anglefire the recoil pit should have an improvised coverto facilitate service of the gun.
46. TESTING TARGETS
Testing targets will be more useful if the fol-lowing improvements are made.
a. The target should be mounted on a flat pieceof masonite, wallboard, or similar material.
b. To insure stability of the testing targetthroughout bore sighting, it should be fastened
Figure 40. Rear view of bore sighting target stand.
98
to a stand in a manner similar to that shown infigure 40.
c. For use in either leveling or canting the testtarget (par. 54b) a mil scale may be inscribed atthe bottom of the target. A small nail at the topmarks the center from which the arc was drawnand provides a hook from which to suspend theplumb line (fig. 41).
d. Vertical reference lines may be drawnthrough the centers of each of the diagrams (fig.
PLUMBLINE
MIL SCALE(Not to Scale)
40 20 0 2Q40
105mm Howitzer Corria e. M2
Figure 41. Mil scale inscribed on testing target.
-99- s~99
42). These lines may be used when the trunnionscan not be leveled, by setting the test target withthe cant angle of the gun. The target is rotateduntil the line of sight through the tube tracksthe reference line when the tube is elevated anddepressed. Similarly, the panoramic telescopeshould be adjusted so that its reticle tracks theappropriate reference line when the tube is ele-vated and depressed.
i F
105mm Howitzer Carrioae. M2
Figure 42. Vertical reference lines drawn on testingtarget.
100
e. To facilitate bore sighting in darkness borea one-sixteenth inch hole through the mountedtesting target at the center of each aiming dia-gram. A flashlight held against the target behindthe appropriate hole provides an aiming point foruse in blackout conditions. Fasten patches of feltpadding on the back of the target covering theregions of each hole so that light from the flash-light won't escape. The flashlight must be lightedonly after it is placed firmly in position. Caremust be taken to prevent disturbing the positionof the testing target.
47. CEASE FIRING
The command CEASE FIRING normally isgiven to the gun section by the chief of section,but in emergencies anyone present may give thecommand. At this command, regardless of itssource, firing will cease immediately. If the gunis loaded, the chief of section will report that factto the executive. The executive acknowledges thisreport by repeating it, "No. (so-and-so) loaded."If CEASE FIRING came from the fire directioncenter, firing is resumed at the announcement ofthe elevation. If CEASE FIRING came fromwithin the firing battery the executive will in-vestigate the condition which caused the commandto be given. When the condition has been cor-rected, firing is resumed by the executive's an-nouncement of the elevation.
~, * __~~ I 101
48. CHANGES IN DATA DURING FIRING
If it is necessary to correct any element offiring data, all firing previously ordered, but notyet executed is stopped by the command CEASEFIRING. Corrected data is then announced. If thegun is not already loaded, the new data will beset off and firing resumed at the announcementof the elevation. If the gun is loaded at theannouncement of a new element of firing data,the new data will be set off. If no change in fuzesetting is required, or if the gun is loaded withpercussion-fuzed shell, firing is resumed at theannouncement of elevation. If the gun is loadedwith time-fuzed shell, and the data requires achange in fuze setting, the chief of section willsuspend firing and that fact will be reported ,othe executive; for example: "No. 2 loaded, time(so much)." In continuous fire, changes in dataare so applied as not to stop the fire or break itscontinuity.
49. TO UNLOAD THE GUN
a. A complete round, once loaded, should alwaysbe fired in preference to being unloaded, unlessmilitary necessity dictates otherwise.
b. When the command UNLOAD is given, No.1 opens the breech slowly; No. 2 standing at thebreech, receives the ejected round or cartridgecase.
102
c. Should the extractor fail to extract the com-plete round, the staff and unloading rammer(head) is used. This will be done only under theimmediate supervision of an officer. He inspectsthe recess in the head of the rammer to assurethat it is free from obstructions. No. 1 theninserts the rammer in the bore until the headincloses the fuze and comes into contact with theprojectile. He pushes and, if necessary, taps therammer staff lightly, or operates the spring-operated rammer, until the round is dislodged(fig. 43). He then pushes it out of the breechand No. 2 receives it.
Figure 43. Nos. 1 and 2 unloading the gun.
103
d. If the cartridge case is extracted but not theprojectile, No. 1 fills the chamber with waste andcloses the breechblock. He dislodges the projectileas in c above. No. 2 then opens the breech, re-moves the waste, and receives the projectile asNo. 1 pushes it to the rear.
e. For further information on unloading seeFM 6-140 and TM 9-325.
f. In case of a misfire, the instructions con-tained in paragraph 85 will be followed.
50. CARE OF AMMUNITION
a. To insure uniform results in firing, to pro-long the life of the tube, and to avoid accident,great care must be exercised in the storage andhandling of ammunition at the battery. Provi-sions of TM 9-1900 applicable to field serviceshould be followed carefully. In the field, condi-tions existing in each position will determine theamount of time, labor, and materials required tostore and preserve the ammunition adequately.If the position is to be occupied for only a fewhours, a tarpaulin spread on the ground may besufficient; for longer periods of time more elabo-rate facilities should be provided.
b. Ammunition must be protected from dam-age. When ammunition is received, it should besorted into lots and placed in the best availablestorage. Powder temperature should be kept asuniform as possible. Ammunition data cards
104
should be kept until after all ammunition for thatlot is expended. Ammunition should be left incontainers until its early use is expected. Protec-tion should be provided against moisture, dirt,direct rays of sun, and, as far as practicable, hos-tile artillery fire and bombing. Protection againstweather, dirt, and sun may be obtained by the useof tarpaulins below and above the ammunition,and suitable dunnage between the layers. Protec-tion against hostile fire may be obtained by theuse of small dispersed stacks, trenches, or dug-outs. Each stack should contain not more than75 rounds and should be not more than four layershigh. Stacks should be at least 10 yards apart.
c. For further information on care of ammuni-tion see FM 6-140, TM 9-325, TM 9-1900, andTM 9-1901.
51. SECTION DATA BOARD
When positions are occupied for more than afew hours, data boards may be used by each sec-tion for recording such items as deflections toaiming points, calibration correction when appro-priate, minimum elevations, data for barrage andcounter preparations, and other data which maybe needed quickly. If such information assumesa standard pattern, the section may paint a formon the back of the shield and chalk in the variousitems of information in the appropriate spaces.
105
CHAPTER 7
BORE SIGHTING AND BASIC PERIODIC TESTS
Section I. GENERAL
52. PURPOSE AND SCOPE
The purpose of this chapter is to outline theprocedures for bore sighting and making basicperiodic tests of on-carriage fire control equip-ment. The procedures covered will include onlythose that may be accomplished at battery level.
53. EQUIPMENT
The following equipment is needed for boresighting and periodic tests:
a. Bore Sights. Front and rear bore sights orimprovised substitutes are necessary for both boresighting and testing. If bore sights are not avail-able, cross hairs may be fastened on the muzzle,and the firing pin hole in the breechblock bush-ing may be used as a rear sighting guide byremoving the firing lock from the closed breech-block.
b. Testing Target. A testing target or suitablesubstitute is needed for both bore sighting andtesting. If a testing target is not available, a
106
2"X4" ON EDGE DRILLED TO FIT OVER SPIKE.AND SHAPED TO LIGHTEN FREE END.
SWING FREEEND TO ALIGNPLUMB LINE ASREQUIRED
ADJUSTABLEGUY LINES -POLE FASTEN WHEN
GUY LINES PLUMB LINE ISIN DESIREDPOSITION
LUMB LINE
PYRAMIDALTENT POLE
Figurwe 44. Improvised plumb line.
107
A,.1
i- And )sK· em AI
Figure 45. Plumb line suspended frosm tree.
clearly defined aiming point 2000 or more yardsfrom the gun may be used to accomplish approxi-mately the same purpose as the testing target.
c. Tools. The section equipment includes all thenecessary tools for bore sighting and testing. Caremust be taken in using the screw drivers andwrenches to insure that damage does not resultthrough carelessness or the use of inappropriatetools.
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d. Plumb Line. Although not essential for boresighting, it is highly desirable that a plumb linebe used in the basic periodic test for maximumaccuracy. The farther from the gun that theplumb line is placed, the longer the line must be.For example, to be effective at 6 feet in front ofthe gun tube, the line must be at least 30 feetlong. To keep such a long plumb line taut it maybe necessary to add weight to it. Wrenches orrocks may be used. The tendency of the weightto swing may be decreased by placing a bucketcontaining water or other liquid under the plumbline so that the plumb bob or other weight ispartially immersed in the liquid. If a convenientmeans of suspension is not readily available, apole may be employed as in figure 44. Additionalheight may be gained by placing the pole atop avehicle or other object. A plumb line strung froma building or tree as in figure 45 is more desirableand should be used if possible. Units in garrisonmay find it convenient to rig a plumb line on abuilding. The line may then be nailed in place sothat it can be used permanently.
Section II. BORE SIGHTING
54. GENERAL
a. Description. Bore sighting is the process ofalining the on-carriage fire control equipment so
213618-52--8
109
that its optical axes are parallel to the axis ofthe bore. It consists of those tests and adjust-ments which are performed by section personnelto insure accuracy in laying for elevation anddirection. The gun should be placed near its centerof traverse prior to bore sighting. All instrumentsand mounts must be positioned securely; theremust be no free play. Bore sighting is conductedbefore firing and when necessary during lulls infiring.
b. Leveling. Although it is not absolutely nec-essary to level the trunnions for bore sighting,it is advisable to do so whenever possible. Accu-rate results can be obtained more readily if thetrunnions are level, because then a correspondingtilt does not have to be introduced in the mountsand testing target. The trunnions should be leveledby leveling the ground under the trails or byblocking up one trail (fig. 46). Approximateleveling may be accomplished by use of the gun-ner's quadrant placed on the breech ring parallelto the trunnions.
(1) Plumb line. The best method to checkleveling is by means of the plumb line.The line is suspended directly in frontof the axis of the bore. The line of sightshould track the plumb line as the tubeis depressed and elevated between maxi-mum depression and at least 1000 milsof elevation. When the trunnions are
110
level, the line of sight tracks the plumbline exactly through all elevations. If thetrunnions are not exactly level and thecant is only slight, to bring the trunnionsinto level, the following technique maybe used. Traverse the tube from centerand shift the trails to bring the line ofsight back on the plumb line. Elevatethe tube to determine whether it morenearly tracks the plumb line. Repeat this
111
.St:ua~i~-Ia~amation
Figure 47. Scribed lines for positioning mount bothlaterally and longitudinally.
experimentation until the line of sighttracks the plumb line exactly.
(2) Gunner's quadrant. In leveling opera-tions using the gunner's quadrant, aquadrant that has been tested (par. 60)and found to be accurate is required.
(3) Gun not level. When it is impossible tolevel the trunnions the cross-level bub-bles cannot be used. If the tube cannotbe leveled the longitudinal-level bubblescannot be used. To permit bore sighting
112
Figure 48. Scribed lines for positioning mountlongitudinally.
when either of these conditions exist,lines should be scribed on the mountsafter a basic periodic test (pars. 59-64)when the mounts are in correct adjust-ment. These scribed lines can be matchedlater, when leveling is impossible, to re-tain the same relationship between theaxis of the bore and moving parts of theon-carriage sighting equipment. After abasic periodic test with the tube andsighting equipment in perfect alinement,
113
Figure 49. Slipping the longitudinal knob index into
coincidence with the bracket index.
use a knife blade or other sharp metal
point to scribe the following lines: (1)Straight across the junction of the cross-leveling segment and the cross-levelingworm housing of the panoramic tele-scope mount (fig. 47(3)). (2) Straightacross the junction of the cross-levelingworm knob shaft and the cross-levelingworm housing (fig. 47(2) ). (3) Straightacross the junction of the rocker and the
114
actuating arm (figs. 47(1) and 48(2)).(4) Straight across the junction of thelongitudinal-leveling (elevation) knobshaft and the bracket (fig. 48(1)). Onmodels having indexes on the elevationknob shaft and on the bracket, the ele-vating knob locking nut is loosened andthe indexes slipped into coincidence (fig.49). Care should be taken that the linesare scribed in the paint only and arenot cut into the metal. Fill the scribedlines with white paint and wipe off theexcess. If conditions prevent bore sight-ing with the tube level, longitudinal com-pensation for an unlevel (elevated ordepressed) tube is measured with thegunner's quadrant and this angle is seton the elevation micrometer instead ofzero when adjustment is being checked(par. 55i).
c. Methods. The four methods of bore sightingare-
(1) Testing target.(2) Distant aiming point.(3) Aiming circle.(4) Standard angle.
55. TESTING TARGET METHODThis method consists of bringing the line of
sight, and indexes of on-carriage fire control
115
equipment into parallel alinement with the tube,
using the aiming diagrams of the testing target
as aiming points.Caution: For weapons modified per MWO ORD
C21-W19, 2 Nov 51, i.e., a bracket added to raisethe sight 8", test target 1-T-283-42 is not correctand must have an additional diagram improvisedabove the sight diagram.
The steps to be followed are listed below:a. Trunnions. Level the trunnions if possible
(par. 54b).b. Tube. Using the gunner's quadrant, level the
tube.
Figure 50. Emplacing breech bore sight.
c. Bore Sights. Place the breech and muzzlebore sights in their proper positions (fig. 50).
d. Testing Target Alinement. Without movingthe gun (except for elevating and depressingslightly when using testing target reference lines)aline the center testing diagram with the line ofsight through the tube (fig. 51). The target nor-mally should be located at least 50 yards in frontof the muzzle.
Figure 51. Alining the testing target.
117
e. Cant Compensation. If the trunnions are
level, level the target by means of a plumb line(fig. 41). If the trunnions are not level, cant the
Figure 52. Loosening a tangent locking screw.
119
target to correspond to the cant of the trunnions.In either case the face of the target is alined sothat it is at right angles to the line of sightthrough the bore.
f. Panoramic Telescope Lateral Alinement. Ifthe trunnions are level, level the cross-level andlongitudinal-level bubbles. If the trunnions arenot level, match the white scribed lines. Zero thesight as in paragraph 22b. If the vertical reticleis not in alinement with its aiming diagram,loosen the tangent locking screws (fig. 52) and
Figure 53. Adjusting the vertical reticle with tangentscrews.
119
igure 54. Alining horizontal recticle by tingFigure 54. Alining horizontal recticle by turning
elevation knob.
adjust the tangent screws (fig. 53) until the ver-tical hair is properly alined. Tighten the lockingscrews and verify the adjustment.
120
g. Panoramic Telescope Horizontal Alinement.If the horizontal reticle is out of alinement, turnthe elevation knob of the telescope (fig. 54) untilit is alined properly. Loosen the clamping screws
Figure 55. Loosening clamping screws.
121
Figure 56. Shifting zero of the elevation knob to its index.
(fig. 55) and shift the scale into coincidence withthe fixed index (fig. 56). Tighten the lockingscrews and verify the adjustment.
h. Elevation Index. Loosen the elevation indexlocking screws. Slip the movable index until itcoincides with the fixed index (fig. 57). Tightenthe screws and verify the adjustment.
i. Range Quadrant. The elevation mechanism istested next. Verify that the locking screws of theelevation micrometer scale are tight. With theline of sight through the tube still on the appro-
122
Figure 57. Shifting elevation index into coincidence.
priate aiming diagram and with the elevationscale near or on zero set the elevation micrometerscale at zero. Level the longitudinal- and cross-level bubbles of the range quadrant with theangle of site micrometer and the cross-levelingworm knob.
j. Elevation Scale Index. If the elevation scaleindex does not coincide exactly with zero, loosenthe screws holding the index plate and slide theplate to zero (fig. 58). Tighten the screws andverify the adjustment.
123
&!mml1rrIJmlllnation
Figure 58. Shifting elevation scale index to zero.
k. Angle of Site Scale. If the angle of site scaledoes not read 3(300) loosen the two lockingscrews of the scale and slip the scale until thenumeral 3 is in coincidence with the index (fig.59). Tighten the screws and verify the adjust-ment.
124
Figure 59. Shifting site scale' to 3(300).
1. Angle of Site Micrometer. If the angle ofsite micrometer does not read zero, loosen theclamping screw in the micrometer knob and slipthe scale to zero (fig. 60). Be sure that the knobdoes not turn and thus throw the longitudinal-level bubble off center. Tighten the locking screwand verify the adjustment.
m. Elbow Telescope.(1) M23 mount. No deflection adjustment
can be made. If the zero range line ofthe elbow telescope does not match the
213618--52 9
125
Figure 60. Adjusting angle of site micrometer scaleto zero.
horizontal line of its aiming diagram,loosen the worm clamping bolt (fig. 61).With a screw driver bring the zero lineinto alinement with the horizontal lineon the aiming diagram. Tighten theworm clamping bolt and verify the ad-justment. If the horizontal reticle is notparallel to the horizontal line of its dia-gram, bring it into alinement by turningthe bracket rotating knob.
126
Fu 61.Looseningworm I bol
Figure 61. Loosening worm clamping bolt of elbowtelescope.
127
(2) M42 mount. There is no provision forleveling the reticle lines. If the verticalreticle is not in alinement loosen the jamnut on the lateral adjusting screw, andwith a screw driver, turn the lateraladjusting screw to aline the reticle.Tighten the jam nut and verify the ad-justment. If the horizontal reticle is notin alinement loosen the jam nut on theelevation adjusting screw, and with ascrew driver turn the elevation adjustingscrew to aline the reticle. Tighten thejam nut and verify the adjustment.
56. DISTANT AIMING POINT METHOD
This method consists of alining the on-carriagefire control equipment and the line of sightthrough the tube on a common point at least2000 yards from the gun. A distant aiming pointmay be used instead of the testing target if thetesting target is not available or if the tacticalsituation makes its use impracticable. The stepsprescribed for the testing target method (par.55a, c and f through m) apply except that thebore sights and optical sights are alined on thesame point instead of on the three diagrams ofthe testing target. Accurate cross leveling of thetrunnions is unnecessary when bore sighting on adistant aiming point because the lines of sightconverge on a single point. It is improbable that
128
the tube will be level, so the white scribed lineswill be used normally.
57. AIMING CIRCLE METHOD
a. General. The aiming circle method may beused when weather or terrain conditions prohibitthe use of the test target method or the distantaiming point method. The aiming circle methoddoes not include a test for determining horizontalerrors. For this method the trunnions must belevel. If, by the aiming circle method, misaline-ment is discovered and corrected it should be veri-fied at the earliest opportunity, by bore sightingwith the test target or distant aiming point. Tofacilitate bore sighting with the aiming circlecertain preparatory steps must be performed.These operations, described in b below, should beperformed after a basic periodic test (Sec. III)when the panoramic telescope mount is in correctadjustment.
b. Preliminary Operations.(1) To insure accuracy the greatest care
must be exercised in all phases of theseoperations. All final movements of theinstruments must be made so that thereticles approach the final position fromleft to right in order to eliminate theeffects of lost motion in the gears.
(2) Parallax. Parallax in the aiming circleand the panoramic telescope must be
129
eliminated. This is done with the aimingcircle after focusing by placing in frontof the eyepiece lens a dark colored card-board or metal parallax shield of thesame diameter as the eyepiece lensfocusing sleeve. The shield should have
Figure 62. Parallax shield.
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a vertically and horizontally leveled slot'A6 inch wide and 1/4 inch long. It maybe held in place with a piece of adhesivetape around the edge of the focusingsleeve. To eliminate parallax in the pano-ramic telescope, a shield of the samediameter as the eyepiece lens housingand having an exactly centered hole 1 6inch in diameter is mounted in front ofthe eyepiece lens (fig. 62). A more per-manent parallax shield may be con-structed of brass or bronze shim stock.When constructed of metal a series offingers approximately 3/6 inch wide and1/4, inch long separated by 1/4 inch spacesshould extend beyond the perimeter ofthe shield. These fingers should be bentalong the circumference of the circleuntil they form an angle of 900 withthe surface of the shield. They serve asa means of clipping the shield in placequickly and permit easy removal. Wherethe eyepiece has a rubber eyeguard, thefingers permit alinement within theguard without its removal.
(3) Bore sight marks. The aiming circlemethod requires that bore sight marksbe located on the top surface of the tubeat the muzzle end and on the rear of thebreech ring (fig. 63). The position of
131
side of the straight edge is still inalinement with the bore sights andparallel to the vertical hair of theaiming circle. Draw a pencil linealong the side of the straight edgeon the upper rear portion of thebreech ring.
(h) Lay the straight edge on the tubeat the muzzle along the same lineof sight and draw a pencil line.
(i) Paint the white stripes on the tubeand breech ring so that the leftedge of the stripes are exactly on-the pencil lines.
c. Procedure. The gun having been preparedas in b above, steps in performing the aimingcircle method of bore sighting are as follows:
(1) Set up the aiming circle 30 to 50 yardsin rear of the gun.
(2) Zero the aiming circle's scales and levelthe instrument.
(3) Elevate the gun until the two bore sight-ing marks are plainly visible from theaiming circle. Do not elevate the tubeany more than is necessary for clear
definition of the edges of the white boresight marks.
(4) By traversing the gun and turning thelower motion of the aiming circle, placethe right edge of the vertical hair exactly
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in line with the left edge of the two bore )anoramic telescope hassight stripes. ct alinement, is an ideal
(5) Check that the trunnions are level by -d angles for later use.elevating and depressing the tube and termined, they may benoting if the two bore sight stripes re- C the alinement of themain parallel to the edge of the vertical 1 more precise methodshair of the aiming circle. If the trun- ient discovered and cor-nions are not level, they must be leveled. test should be verified
(6) With the upper motion of the aiming )d at the earliest oppor-circle turn to the objective lens of the standard angle methodpanoramic telescope. Make certain that that the position of theequal amounts of the housing appear on lect to the nonrecoilingeach side of the vertical hair. en the standard angles
(7) Read the angle on the azimuth scales of ) of this, the recoil sys-the aiming circle. see that it contains the
(8) Insure that the azimuth scales of the oil before determiningtelescope are set at zero and that theindexes are in coincidence. ons. The procedure for
(9) Set the angle from the aiming circle Yles is as follows:((7) above) on the azimuth micrometer battery, scribe lines inscale of the panoramic telescope. -k the position of parts
(10) Adjust the tangent screws until the ver- recoil with respect totical hair of the telescope is exactly on ) not move in recoilthe center of the objective lens of theaiming circle. Recheck the angle settings ;he trunnions.and the alinement of the vertical hairs. n using a testing target.
,pe fasten a bright com-58. STANDARD ANGLE METHOD left horizontal witness
a. General. When positions are occupied in com- pin to project to thebat, the necessity for speed in opening fire or the e (fig. 65).
135 1'37
yonIIII ation
:ouflage discipline mayethods previously de-er such circumstancesaxis of the panoramic
X ~:~-~ 7 ^ f : ~ ty - ' I is of the bore may be·:_,f ;; I Igarr310L ! 4ferring to a selected
40 30 2o i o eflection and elevationhe line of sight of theint on the muzzle willrd angles. At the basic
IC- - -
Figure 65. Sight picture of projecting pin.
(5) Fasten the telescope parallax shield inplace over the eyepiece (fig. 62). a
(6) Verify that the elevation index andmicrometer on the telescope are at zero.
(7) Elevate the tube until it is approximatelylevel with the top of the panoramic tele-scope.
(8) Level the bubbles of the telescope mountand refer the telescope to the junction of
mark normal position ofthe pin with the muzzle. Adjust the tube ark normal position ofparts.
1 38 j1
elevation and turn the azimuth microm-eter knob until, with the bubbles level,the horizontal and vertical hairs of thetelescope are exactly on the junction ofthe pin with the muzzle (fig. 65).
(9) Read the angle from the panoramic tele-scope to the nearest one-fourth mil.Since the graduations are to the nearestmil it is necessary to interpolate to thenearest one-fourth mil. This is the stand-ard azimuth (horizontal) angle for thegun tested.
(10) With either the range quadrant or gun-ner's quadrant measure the elevation ofthe tube to the nearest one-fourth mil.This is the standard elevation (vertical)angle for the gun tested.
(11) With a knife blade or other sharp metalpoint scribe lines in the paint on thefollowing parts:(a) Straight across the junction of the
cross-leveling segment and the cross-leveling worm housing (fig. 47 (3)).
(b) Straight across the junction of thecross-leveling worm housing andthe cross-leveling worm knob shaft(fig. 47(2)).
(c) Straight across the junction of therocker and the actuating arm (figs.47(1) and 48(2)).
139
(d) Straight across the junction of theelevation knob shaft and the bracket(fig. 48(1)).
(12) Fill the scribed lines with red paint andwipe off the excess.
c. Procedure. Once the standard angles havebeen determined, steps in performing the stand-ards angle method of bore sighting are as follows:
(1) Verify that the parts that move in recoilare in the same position with respect tothe nonrecoiling parts as they were whenthe standard angles were determined.
(2) Verify that the trunnions are canted notmore than 10 mils; if convenient, levelthe trunnions.
(3) With adhesive tape fasten a pin in theleft horizontal witness mark so that thepin projects out to the left of the muzzle.
(4) Using the range quadrant or gunner'squadrant elevate the tube to the stand-ard elevation angle.
(5) Place the parallax shield on the eyepieceof the telescope.
(6) Set the standard azimuth angle on thepanoramic telescope. Make sure that thered scribe lines are in coincidence andset off the standard azimuth angle on thepanoramic telescope.
(7) If the vertical reticleJ.is not exactly onthe junction of the pin and the muzzle.
140 -
adjust the tangent screws until the ver-tical reticle is properly alined.
(8) If the horizontal reticle is not exactly onthe junction of the pin and the muzzle,turn the elevating knob of the panoramictelescope until it is properly alined. Ad-just the zero of the elevation knob scaleso that it is in alinement with the index.
Section III. BASIC PERIODIC TESTS
59. GENERAL
Basic periodic tests are performed by the sec-tion under the supervision of the battery executiveand the artillery mechanic. These tests are per-formed at the discretion of the unit commander.Suggested times for performance are: once eachyear if the gun is used only for nonfiring train-ing; once every 3 months if the gun is fired, assoon as possible after extensive use, accidents, ortraversing extremely rough terrain; and when-ever the gun fires inaccurately for no readilyapparent reason. The tests reveal whether or notthe on-carriage sighting equipment and certainoff-carriage equipment are in correct adjustment.For the on-carriage equipment to be in correctadjustment, the following conditions must be met:
a. The line of sight of the panoramic telescopeand of the elbow telescope must be parallel to theaxis of the bore.
213618°-52-10
- t I,~~~~~141
b. All indexes and scales, except the angle ofsite scale, must read zero. The angle of site scalemust read 3(300).
c. All bubbles must be in adjustment and level.d. The sighting equipment must satisfactorily
meet all tests described in paragraphs 54-58.e. Prior to all tests of on-carriage fire control
equipment it is desirable that the trunnions be aslevel as possible. Leveling the trunnions is mosteasily accomplished by raising or lowering onetrail (fig. 46). The best check that the trunnionsare level is accomplished by seeing that the axisof the bore tracks a plumb line as described inparagraph 54b.
60. TEST OF GUNNER'S QUADRANT
a. General. The gunner's quadrant must be inproper adjustment before conducting tests andadjustments of other sighting and fire controlequipment. Inspect the shoes of the gunner's quad-rant for dirt, nicks, or burrs. Similarly, inspectthe leveling plates on the upper surface of thebreech ring. Dirt, nicks, or burrs on these sur-faces will cause the instrument to give inaccuratereadings.
b. End-for-End Test.(1) Set both the index arm and micrometer
scale of the gunner's quadrant at zero,making sure the auxiliary indexes match.
142 _
(2) Place the quadrant on the leveling platesof the breech ring, the line-of-fire arrowpointing toward the muzzle, and centerthe quadrant bubble by turning the ele-vating handwheel (fig. 66).
A
Figure 66. Leveling bubble of gunner's quadrant, normalposition, end-for-end test.
(3) Reverse the quadrant on the levelingplates (turn it end-for-end) (fig. 67).If the bubble recenters, the quadrant isin adjustment and the test is completed.
143
Figure 67. Centering bubble of gunner's quadrant,quadrant reversed.
(4) If the bubble does not recenter, try tocenter it by turning the micrometerknob.(a) If bubble centers, read black figures
and divide by two. This is the cor-rection.
(b) Place correction on micrometer;level tube using elevation handwheel.
(c) Check by again reversing the quad-rant. Bubble should center.
(5) If bubble doesn't center as in (4) above,
144
move the arm down one graduation (10mils).(a) Turn micrometer until bubble cen-
ters.(b) Take reading on micrometer add ten
to it and divide sum by two. Thisis the correction.
(c) Place this reading on micrometerleaving the arm at minus 10; leveltube with elevation handwheel.
(d) Check by reversing quadrant onseats. Bubble should center.
(e) Quadrant should be sent to Ordnanceif correction of error amounts tomore than plus or minus 0.4 mils.
c. Micrometer Test.(1) Set the index arm to read 10 mils on the
graduated arc and set the micrometerscale at zero.
(2) Place the quadrant on the leveling plateson the breech ring, the line-of-fire arrowpointing toward the muzzle, and centerthe quadrant bubble by elevating the tube.
(3) Set the index arm at zero on the gradu-ated arc and turn the micrometer onerevolution to read 10 mils.
(4) Reseat the quadrant on the levelingplates. The bubble should center.
Caution: Do not disturb the laying ofthe tube.
145
Seufnlrltmmuon
(5) If the bubble does not center, the mi-crometer is in error and must be ad-justed by ordnance personnel.
d. Comparison Test. Compare readings takenat low, medium, and high elevations with all ofthe gunner's quadrants of a battery on a singlegun whose quadrant seats have been accuratelycross leveled. Any quadrant differing from theaverage by more than .4 mil at any elevationshould be sent to ordnance for adjustment.
e. Correction. When a gunner's quadrant re-quires a correction as determined by the end-for-end test, this correction is not carried duringfiring but is applied only when making sight testsand adjustments.
61. TEST OF RANGE QUADRANT
a. Cross-level Tests.(1) The gun and carriage being level (axis
of bore and axis of trunnions), centerthe cross-level bubble.
(2) Turn the elevation knob throughout itslimits of motion.
(3) The cross-level bubble should remaincentered to within one-half vial gradua-tion; if it does not, the level vial isincorrectly alined and the weapon shouldbe sent to an ordnance unit for adjust-ment.
146
b. Pivot Azimuth Alinement Test.(1) Place the breech and muzzle bore sights
in their proper positions in the tube.(2) Center the previously tested cross-level
bubble.(3) Elevate and depress the tube, checking
to see that the bore sights track a plumbline placed in front of the tube; at thesame time watch the cross-level bubble.
(4) The bubble should remain centered towithin one-half vial graduation.
(5) If the bubble moves off center in excessof this amount, the pivot is not alinedin azimuth with the tube; send theweapon to an ordnance unit for adjust-ment.
c. Pivot Vertical Alinement Test.(1) Level the tube using the previously tested
gunner's quadrant.(2) Center the longitudinal-level bubble by
turning the angle of site micrometerknob.
(3) Operate the cross-leveling knob through-out the limits of the motion; the lon-gitudinal-level bubble should remaincentered.
(4) If the bubble moves off center in excessof one-half vial graduation, either thepivot is not alined vertically with the
147
tube. or the level vial is not correctlyalined; send the weapon to an ordnanceunit for adjustment.
d. Comparison Test.(1) Compare the readings indicated by the
gunner's quadrant with those on theelevation quadrant at low, medium, andhigh elevations of the tube.
(2) If the two instruments do not agree atall. elevations, send the weapon to anordnance unit for adjustment.
e. Angle of Site Scale Test. Level the tube withthe gunner's quadrant, cross level the range quad-rant, and set the scales at zero. Center thelongitudinal-level bubble by turning the angle ofsite micrometer knob. The angle of site scaleshould read 3 (300) and the angle of site microm-eter should read zero; if they do not, adjust thescales.
62. TEST OF AZIMUTH COMPENSATING MECHANISMOF PANORAMIC TELESCOPE MOUNT
a. General. The purpose of this test is to de-termine whether the azimuth compensating mech-anism of the telescope mount actually keeps thetube in the correct vertical plane at all elevations.One of the tests listed below, in order of prefer-ence, should be performed.
b. Test Wherein Trunnions Need Not Be Level(Plumb Line Required). By using a plumb line
148
slllU~llllo o
as a vertical reference plane this test reveals thetotal amount of error that exists between the cen-ter of the reticle pattern and the direction inwhich the tube points. Steps are as follows:
(1) With bore sights in place and tube nearzero elevation, traverse so line of sightthrough the tube is on the plumb line.
(2) With the sight mount leveled, move onlythe sight to refer to a distant sharplydefined aiming point (in any direction).Use the elevation knob of the sight tobring the horizontal reticle to the aim-ing point.
(3) Elevate the tube to maximum elevationor to the top of the plumb line. Traverse ifnecessary to bring line of sight throughtube back to plumb line.
(4) Level the panoramic telescope mountboth laterally and longitudinally.
(5) Sight through the telescope to determinewhether or not it is still on the aimingpoint.
(6) If the sight is off the aiming point inexcess of 1 mil in deflection and/or one-half vial graduation in elevation sendthe weapon to 'an ordnance unit for ad-justment.
c. Test With Trunnions Level. Using the leveledtrunnions and tube for control this test deter-
149
mines whether errors exist in the actuating armpivot and/or level vials. Leveling may be accom-plished by a plumb line check (par. 53d) or bycross leveling with the gunner's quadrant on thebreech ring. If cross leveling is accomplished withthe gunner's quadrant on the breech ring, resultsof the test are no more accurate than the parallelrelationship of the trunnions to the top surfaceof the breech ring. Steps are as follows:
(1) Cross level test of telescope mount. Thetelescope mount cross-level bubble mustbe in proper adjustment before conduct-ing the remainder of this test of theazimuth compensating mechanism.(a) Center the cross-level bubble and
place the line of sight of the pano-ramic telescope on a sharply definedaiming point.
(b) Elevate the tube to maximum ele-vation while keeping the telescopemount level longitudinally.
Note. Do not readjust the cross-levelbubble after the initial setting.
(c) The line of sight must not deviatefrom the target by more than 1 milat any elevation checked nor maythe cross-level bubble travel morethan one-half vial graduation. Ifdeviation in excess of the toleranceoccurs, the level vial or pivot is
1 50
incorrectly alined. Send the weaponto an ordnance unit for adjustment.
(2) Vertical alinement test of telescopemount.(a) Level the tube longitudinally with
the gunner's quadrant.(b) Center the longitudinal-level bubble.(c) Operate the cross-leveling knob
throughout the limits of motion;the longitudinal level bubble shouldremain centered within one-half vialgraduation. If the bubble moves inexcess of the tolerance, either thelevel vial or the actuating arm pivotis not alined correctly and the weap-on should be sent to an ordnanceunit for adjustment.
d. Test with Gunner's Quadrant on Socket.Using the top surface of the socket for controlthis test determines the relationship of the levelbubbles to the top surface of socket. If the socketis bent or if the top surface is unlevel, results ofthe test will be inaccurate. With the tube andtrunnions approximately level, place a steel orglass plate having parallel sides on top of thetelescope mount. Level the telescope mount bothcrosswise and longitudinally by turning the crossleveling and elevation knobs, using the tested gun-ner's quadrant as a level. If the elevation indexeson the rocker and the actuating arm and those
151
on the elevation knob and the shaft do not match,adjust them by moving the adjustable index onthe rocker or by adjusting the elevation knobindex as needed. If the cross- and longitudinal-level bubbles are not centetred within one-halfvial graduation, adjustment must be made byordnance personnel.
63. ORDNANCE CHECK
It is not contemplated that using units willhave the necessary facilities, tools, or skilledmechanics to perform the more precise tests andadjustments of sighting and fire control equip-ment. When deficiencies recur or when defectscannot be corrected in the field, ordnance checksshould be scheduled.
64. FUZE SETTERS
a. General. Examine the stop which fits intothe slot in the movable time ring and the adjust-ing pawl which engages the notch in the fixedfuze ring to see that their edges are not burredor bent. Depress the adjustable pawl against itsspring to see that the movement of the pawl isfree. In the following test be sure to test the fuzesetter with the fuze for which it is designed; thetime scale on the fuze setter must have the samegraduations as the time ring on the fuze.
b. Time Scale Test. Set the corrector to 30 andset any convenient time on the time scale. Test
152 0
Won
the time scale of the fuze setter by setting severalfuzes.
Caution: Before setting a fuze, make sure thatthe "T" and "C" screws (of the fuze setter) aretight to prevent any slipping of the scale indexeswhen the handle of the fuze setter is rotated. Thetime set on the fuze should agree with the timesetting on the fuze setter within one-fourth ofthe smallest graduation on the fuze time ring.The tolerance amounts to 0.05 seconds for fuzeshaving 0.2 second graduations, and 0.125 secondsfor fuzes having 0.5 second graduations. If thefuzes set do not agree with the time set on thefuze setter, repeat the test as a check with a dif-ferent setting. If the fuzes set still do not agreewith the fuze setter, refer the instrument toordnance for adjustment.
Caution: Do not set any one live fuze more thantwice. The fuze from a dud must never be used.Reset all fuzes to SAFE and replace the safetywire or cotter pin.
153
S-
CHAPTER 8
MAINTENANCE AND INSPECTIONS
65. GENERAL
Maintenance and inspection is essential to in-sure that the gun section is prepared to carry outits mission immediately. Systematic maintenanceand inspection drills provide the best insuranceagainst unexpected breakdown at the criticalmoment when maximum performance is essential.
66. DISASSEMBLY, ADJUSTMENT, AND ASSEMBLY
Disassemblies and adjustments of the weaponauthorized to be performed by battery personnelare prescribed in TM 9-325, supplemented by in-structions contained in Department of the ArmySupply Catalogs, ORD 7 SNL C 21, ORD 8 SNLC 21, and ORD 9 SNL C 21. No deviation fromthese procedures is permitted except when author-ized by the responsible ordnance officer.
67. RECORDS
a. The principal records pertaining to theweapon are the Artillery Gun Book (00 Form5825), a field report of accidents (SR 385-310-1),
154
and the unsatisfactory equipment report (DAForm 468). Information on the purpose and useof these records may be found in the formsthemselves.
b. The chiefs of sections, battery executive,and battery commander also should keep semi-permanent records on their weapons for informa-tion and guidance.
68. MAINTENANCE
For detailed instructions concerning mainte-nance of the 105-mm howitzer see TM 9-325 andLO 9-325. For detailed instructions concerningmaintenance of the vehicle being used as a primemover, see the technical manuals and lubricationorders pertaining to that vehicle.
69. INSPECTIONS
Regular inspections are required to insure thatmat6riel is maintained in serviceable condition.
a. The chief of section is responsible for theequipment within his section. He should inspectit thoroughly each day. If he sees the need forrepair or adjustment, he notifies the battery exec-utive immediately so that the necessary actionmay be taken.
b. The executive, accompanied by the artillerymechanic, should make a daily spot-check inspec-tion. Each day he inspects different parts of theweapons thereby insuring complete coverage every
155
few days. At least once a month, the executivemakes a thorough mechanical inspection of theweapons, auxiliary equipment, tools, and spareparts.
c. Battery, battalion, and higher commandersshould make frequent command inspections toassure themselves that the equipment in theircommands is being maintained at prescribedstandards of condition, appearance, and complete-ness.
d. For details on inspecting the 105-mm how-itzer see TM 9-325. For details on inspecting thevehicle being used as prime mover see the appro-priate technical manual for that vehicle. Deficien-cies found during inspections should be remediedpromptly.
e. Duties of individuals in performing the nec-essary inspections and maintenance of the gunare outlined in the tables IV and V. Work willbe made routine, thorough, and rapid by followingthe drill outlined in these tables. When the sectionis reduced in strength the chief of section mustreassign duties to insure that all maintenancesteps are completed.
70. INSPECTION DUTIES BEFORE OPERATION(MARCH)
The inspection performed before operation isa final check on mat6riel prior to leaving themotor park for training in the field, the bivouac
156
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area for combat, or before displacement. Afterinspection, and when all deficiencies have beencorrected, the section is ready to go into action.
71. INSPECTION DUTIES DURING THE MARCH
The inspection performed during operation isa constant check on the operation of the mat6rieland the security of equipment to insure that allmateriel goes into combat in the best possiblecondition. There is no command for this inspec-tion as it is carried on constantly. The responsi-bilities and duties are as shown below:
a. Chief of Section.(1) Rides in cab with driver and supervises
march discipline.(2) Assigns duties for antiaircraft and anti-
mechanized security.(3) Observes prime mover instruments and
controls for proper functioning, and lis-tens for unusual noises indicating mal-functioning of the vehicle or gun.
b. Gunner.(1) Listens for abnormal or unusual noises
and observes towed load for security.(2) Signals chief of section in case of mal-
function.c. Nos. 1-7 inclusive.
(1) Perform duties as antiaircraft and anti-mechanized security sentries as assignedby chief of section.
21368 6 18°--52-11
_ : 157
4 - -di
(2) Listens for abnormal or unusual noisesindicating malfunction of vehicle or gun.
d. Driver. Performs during operation duties asprescribed in TM 21-305.
72. INSPECTION DUTIES DURING HALT
The inspection at the halt is made to insure thatthe gun and prime mover are in good condition.This inspection checks items which cannot bechecked during the march and is performed assoon as a halt is made. The chief of section, onbeing told length of halt, will divide halt timebetween relief and maintenance. Duties are asshown in table V.
73. INSPECTION DUTIES PRIOR TO AND DURINGFIRING
Inspection before and during firing is a con-tinuing inspection to insure proper functioningof mat6riel. No command is necessary; each mem-ber of the section performs appropriate inspec-tions throughout pre-firing and firing periods asshown below:
a. Chief of Section.(1) Supervises and commands section as pre-
scribed in chapters 4 and 5.(2) Supervises servicing of recoil system and
testing and adjustment of sighting andfire control equipment prior to firing.
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b. Gunner.(1) Tests and adjusts sighting and fire con-
trol equipment prior to firing, providedsufficient time is available.
(2) Performs inspection duties in firing asprescribed in chapters 4 and 5.
c. No. 1.(1) Tests and adjusts elbow telescope prior
to firing.(2) Performs inspection duties in firing as
prescribed in chapters 4 and 5.d. Nos. 2-7. Perform appropriate inspection
as prescribed in chapters 4 and 5, and any otherduties as directed by chief of section.
e. Driver. The driver moves his vehicle to themotor park, usually under the direction of thefirst sergeant, and performs after operation dutiesas prescribed in TM 21-305.
74. INSPECTION DUTIES AND MAINTENANCE AFTEROPERATION
After operation, the gun is immediately givenwhatever servicing and maintenance is needed toprepare it in every way for further sustainedaction or to determine the need for maintenanceby higher echelons. These operations may be per-formed in the motor park, bivouac area, or com-bat position. Inspections are as shown in table VI.
159
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75. DUTIES IN WEEKLY INSPECTION ANDMAINTENANCE
In garrison these duties are performed weekly.On maneuver or in combat they are performedafter each field operation.
a. Chief of Section.(1) Supervises section in weekly inspection
and maintenance of gun, tools, acces-sories, and equipment. (See TM 9-325and Lubrication Order 9-325 for furtherdetails.)
(2) Obtains assistance of the artillery me-chanic for operations requiring skill andtools beyond the capabilities of the sec-tion.
b. Gunner and Cannoneers Nos. 1-5 Inclusive.Perform normal maintenance as directed by thechief of section.
c. Driver and Cannoneers Nos. 6 and 7. Whendirected to do so by the chief of section, assistthe motor mechanic in the performance of theprescribed vehicle weekly inspection and mainte-nance.
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CHAPTER 9
DECONTAMINATION OF EQUIPMENT
76. GENERAL
Equipment which has been contaminated bychemical, biological, or radiological agents con-stitutes a danger to personnel. Contaminationmeans the spreading of an injurious agent inany form and by any means. Persons, objects, orterrain may be contaminated. Decontaminationis the process of making any contaminated placeor object safe for unprotected personnel. This canbe done by covering, removing, destroying, orchanging into harmless substances the contami-nating agent or agents. Generally, only equip-ment contaminated by persistent agents need bedecontaminated.
77. DECONTAMINATION FOR CHEMICAL AGENTS
a. Ammunition. With rags, wipe off visiblecontamination from projectiles. Apply DANC(decontamination agent, noncorrosive, M4), wipewith gasoline-soaked rag, then dry. If DANC isnot available, scrub with soap and cool water.Slurry (equal weights of water and chloride oflime) can be used on contaminated ammunition
161
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containers, but it must not be allowed to penetrateto the ammunition itself.
b. Instruments. If exposed to corrosive gases,clean instruments as soon as possible with alcohol(or gasoline, if no alcohol is available), and apply
a thin coat of light machine oil. A rag dampenedwith DANC may be used, followed by dryingwith a clean rag and then applying a coat ofmachine oil. DANC injures plastic or hard rubbersurfaces.
c. Weapons. Remove dirt, dust, grease, and oil.Do not apply wet mix but allow surfaces to airafter soil and dirt have been removed. DANCcan be used on all metal surfaces except the bore.Also effective on metal are hot water, cleaningsolvent, or repeated applications of gasoline onswabs. If the emergency use of gasoline-soakedswabs is.made (FM 21-40), extreme care mustbe taken to insure that the gasoline does notspread the contamination and that no gasoline inliquid or vapor form remains. This excess wouldbe ignited when the gun is fired. After decon-tamination, weapons are dried and oiled.
d. Automotive Equipment. Light contaminationfrom spray can be decontaminated by aerationalone. For heavier contamination use DANC oninterior or exterior surfaces which personnel arelikely to touch. For larger area decontamination,wash vehicle with water and scrub painted sur-faces with soap and water.
1021
78. DECONTAMINATION FOR BIOLOGICAL ANDRADIOLOGICAL AGENTS
a. General. After a contaminating attack, re-covery of equipment may be achieved either bywaiting, to permit the decay of contamination, orby active decontamination, to reduce danger to alevel where it is no longer a significant hazardto operating personnel. Decontamination may beeither rough or detailed, depending on the urgencyof the military situation. The procedure adoptedwill be a command decision.
b. Rough Decontamination. Rough decontami-nation is performed when urgency is the mainfactor. Its purpose is to reduce contaminationsufficiently to permit personnel to work with, orclose to, equipment for limited periods. Roughdecontamination may be achieved by means ofwater or steam if available. Soap or other deter-gent used in conjunction with water or steamaids in decontamination.
c. Detailed Decontamination. Detailed decon-tamination, in which the emphasis is on thorough-ness, will be carried out in rear areas and repairbases and includes procedures of surface decon-tamination, aging and sealing, and disposal.
79. REFERENCES
For further information on decontaminationsee FM's 17-59 and 21-40, TM 3-220, and TF3-1407.
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oron
CHAPTER 10
DESTRUCTION OF EQUIPMENT
80. GENERAL
a. Tactical situations may arise when it be-comes necessary to abandon equipment in thecombat zone. In such a situation all abandonedequipment must be destroyed to prevent its useby the enemy.
b. The destruction of equipment subject to cap-ture or abandonment in the combat zone will beundertaken only upon authority delegated by divi-sion or higher commanders.
c. All batteries must prepare plans for destroy-ing their equipment in order to reduce the timerequired should destruction become necessary.The principles to be followed are:
(1) Plans for destruction of equipment mustbe adequate, uniform, and easily carriedout in the field.
(2) Destruction must be as complete as theavailable time, equipment, and personnelwill permit. Since complete destructionrequires considerable time, the moreessential parts are destroyed first.
164
(3) The same essential parts must be de-stroyed on all like units to prevent theenemy from constructing complete unitsfrom damaged ones.
(4) Spare parts and accessories must begiven the same priorities as the partsinstalled on the equipment.
81. METHODS
To destroy equipment adequately and uni-formly, all personnel of the unit must know theplan and priority of destruction and be trainedin the methods of destruction.
82. REFERENCES
For detailed information on destruction of bar-rel assembly and recoil mechanism, carriage ormount, tires, and fire control equipment, seeTM 9-325; for ammunition, see TM 9-1901. Fordestruction of vehicle, see the TM appropriateto the vehicle being used as prime mover.
165
CHAPTER 1 1
SAFETY PRECAUTIONS
83. GENERAL
Safety precautions to be observed in trainingare prescribed in SR 385-310-1. Additional in-formation is found in FM 6-140, TM 9-325, andTM 9-1900. The more important safety precau-tions are summarized in the following paragraphs.
84. AMMUNITION
a. All ammunition at the firing position mustbe so placed that it is protected against explosionin case of accident at the gun position. Flamesand explosive materials such as gasoline must bekept away from the ammunition. Ammunitionshould be protected from direct rays of the sunby use of a tarpaulin or other suitable covering.
b. Battery personnel must not attempt to dis-assemble fuzes or remove primers from rounds.
c. If for any reason a round is not fired afterthe time fuze has been set, the fuze must be resetto SAFE before it is restowed.
d. All rounds not fired which have been pre-pared for firing must be checked by the chief ofsection, to insure that all seven powder increments
166
Silllpjon
are present in proper order and condition, andthat they are of the proper lot number. He alsoverifies that the lot number on the ammunitioncorresponds to the lot number on the container.A battery officer must certify that .ammunitionhas been properly reassembled. (For further de-tails, see FM 6-140.)
85. MISFIRES
a. In the event of a misfire two more attemptsare made to fire the gun. If it does not fire, waittwo minutes from the time of the last attemptbefore the executive commands UNLOAD.
b. Upon the command to unload, the breech isopened to extract the cartridge case. Should thecomplete round be extracted, the projectile isseparated from the cartridge case. Immediatelyinspect the primer in the base of the cartridgecase to determine whether the indent is normal.The cartridge case is thrown clear of all person-nel to prevent injury in case of a hang-fire. Theprojectile is reloaded with another cartridge caseand firing is resumed.
c. See TM 9-325 for action to be taken in casethe indent on the primer is light or if there isno indent, indicating that the firing lock is notfunctioning properly.
167
Srion
86. DRILL AND FIRING
a. The gun is kept unloaded except when firingis imminent.
b. Members of the gun section pass in rear ofthe gun when going from one side to another.
c. Personnel must stay a safe distance from thebreech to prevent injury when the gun recoils.
d. During firing personnel should use waste intheir ears to protect eardrums against injury.
e. In training there must always be a safetyofficer for each artillery unit firing. For duties ofthe safety officer see FM 6-40.
168
APPENDIX I
REFERENCES
AR 600-70 Badges.AR 750-5 Maintenance Responsibilities and Shop
Operation.ATT 6-1 Training Test for Field Artillery Bat-
tery.ATT 6-2 Training Tests for Field Artillery Bat-
talion Firing.ATT 6-5 Training Tests for Light and Medium
Field Artillery Battalion, InvolvingDisplacement and Continuous FireSupport.
SR 110-1-1 Index of Army Motion Pictures, Kine-scope Recordings and Film Strips.
SR 310-20-series Military Publications.SR 320-5-1 Dictionary of United States Army
Terms.SR 385-310-1 Regulations for Firing Ammunition for
Training, Target Practice, and Com-bat.
SR 615-25-15 Military Occupational Specialties.SR 615-25-20 Career Fields.FM 5-15 Field Fortifications.FM 5-20 Camouflage, Basic Principles.FM 5-20B Camouflage of Vehicles.FM 5-20D Camouflage for Field Artillery.FM 5-25 Explosives and Demolitions.FM 6-40 Field Artillery Gunnery.
169
FM 6-101 Tactics and Technique Battalion andBattery Motorized.
FM 6-125 Qualification Tests for Specialists, FieldArtillery.
FM 6-140 The Field Artillery Battery.FM 21-5 Military Training.FM 21-8 Military Training AidsFM 21-40 Defense Against Chemical Attack.FM 25-10 Motor Transport.TM 3-220 Decontamination.TM 5-267 Camouflage.TM 6-605 Field Artillery Individual and Unit
Training Standards.TM 9-325 105-mm Howitzer M2A1; Carriages
M2A1 and M2A2; and CombatVehicle Mounts M4 and M4A1.
TM 9-575 Auxiliary Sighting and Fire ControlEquipment.
TM 9-850 Cleaning and Preserving, Sealing, andRelated Materials Issued for Ord-nance Materiel.
TM 9-1325 105-mm Howitzer, M2 and M2A1;Carriages M2A1 and M2A2; andCombat Vehicle Mounts M3 and M4.
TM 9-1527 Gunner's Quadrants M1 and M1918,and Machine Gun Clinometer M1917.
TM 9-1545 Telescope Mounts, and Range andElevation Quadrants for Motor Car-riages, Field Artillery and Anti-aircraft Artillery.
TM 9-1582 Panoramic Telescopes, All Types.TM 9-1590 Fuze Setters for Field Artillery.TM 9-1900 Ammunition, General.TM 9-1901 Artillery Ammunition.TM 9-2300 Artillery Mat6riel and Associated
Equipment.
170
TM 21-300 Driver Selection Training and Super-vision, Wheeled Vehicles.
TM 21-305 Driver's Manual.TM 37-2810 Motor Vehicle Inspection and Preven-
tive Maintenance Services.DA ORD Supply Catologs:SNL C-21 Howitzer, 105, M2A1; Carriage How-
itzer, 105-mm, M2A1 and M2A2.SNL K-1 Cleaning and Preserving Materials.SNL R-1 Ammunition for Light Artillery.SNL R-3 Fuzes and Primers.SNL R-7 Demolition Mat6riel, Land Mines, and
Fuzes.
SD ,,171
APPENDIX II
TRAINING
Section I. GENERAL
1. PURPOSE AND SCOPE
The purpose of this appendix is to present theabsolute minimum requirements for training thepersonnel of a gun section in the performance oftheir duties in service of the gun. It includesgeneral information on the conduct of training, aminimum training schedule, and tests to be givenfor the qualification of gunners.
2. OBJECTIVES
The objectives are speed in training cannoneersin their individual duties; and, through drill,' toweld them into an effective, coordinated teamable to function efficiently in combat. Duringtraining, supervisors may well keep in mind theproficiency sought by Army Training Tests(ATT) 6-1, 6-2, and 6-5. Maximum efficiency isattained through continuous drills.
172
3. CONDUCT OF TRAINING
a. Training will be conducted in accordancewith the principles laid down in FM 21-5. Its goalshould be the standards set forth in FM 6-125,TM 6-605, SR 615-25-15, and SR 615-25-20.
b. In general, individual training is conductedby noncommissioned officers as far as practicable.Officers are responsible for training plans, forconducting unit training, and for supervising andtesting individual training.
c. Throughout training, the application of priorinstruction to current training must be empha-sized.
d. A record of the training received by eachindividual should be kept. This may be done byeach chief of section keeping a progress card foreach man in his section. This card should showeach period of instruction attended, tests taken,and remarks pertaining to progress. Progresscards should be inspected frequently by the bat-tery executive to make sure that they are beingkept properly and to determine the state oftraining. Requiring the chief of section to keepthese records emphasizes his responsibility towardhis section.
e. The necessity for developing leadership andinitiative in noncommissioned officers must beemphasized constantly throughout training.
2136180°-52 12
-a _-~~~~~ 173
- ation
4. STANDARDS TO BE ATTAINED
A satisfactorily trained gun section must becapable of performing the following functions inthe times indicated (TM 6-605):
a. Firing 10 rounds (drill ammunition) at dif-ferent deflections, elevations, and time fuze set-tings, using the same charge, in 3 minutes by dayand 4 minutes by night. Changes in data shouldbe typical for a time bracket adjustment; data isannounced from prepared cards.
b. Performing after-firing care and mainte-nance of gun and carriage. The gun being inposition, clean and lubricate, disassemble andassemble the breech and firing mechanism, andinspect the weapon, in 30 minutes by day and40 minutes by night. All materials and tools re-quired should be available at the position.
c. Performing 6-months inspection and mainte-nance of the gun and carriage. The gun preparedfor action in the gun park, clean and lubricate,as authorized, all parts and assemblies, andprepare for ordnance inspection in 2 hours. Allmaterials and tools required should be availablein the gun park.
d. Each member of the gun section should knowthe duties of all other members of the section andbe able to perform efficiently in all positions. Seeparagraphs 8 through 21 in app. II for tests tobe given for the qualification of gunners.
174
Section II. MINIMUM TRAINING SCHEDULE
5. GENERAL
The training schedule outlined in paragraph 7of this appendix is a guide to meet the minimumtraining requirements for personnel of a gun sec-tion in subjects covered in this manual.
6. INDIVIDUAL PERIODS
a. Individual periods of training in service ofthe gun should be arranged, along with otherbattery training, into a balanced training pro-gram taking into consideration the basic prin-ciples of training.
b. In general, except for service practice, peri-ods on any subject should not be longer than 1hour. Gun drill periods should be for only one-half hour and should be conducted in a vigorousmanner.
c. Gun drill periods should be preceded andfollowed by periods on subjects that will be logi-cally related to the drill. For example, precede aperiod of gun drill with a period of testing andadjustment of sighting and fire control equipment,and follow it with a period on inspection andmaintenance drills. A period on aiming post dis-placement correction may come between twoperiods of gun drill.
175
S~ m~mrrtion
d. TM 9-325 provides information on which tobase periods of instruction on description, char-acteristics, and functioning of the gun; familiari-zation with the gun, including breech and firingmechanism, barrel assembly and slides, recoilmechanism, equilibrator, elevating mechanism,sighting and fire control equipment; and fieldassembly and malfunction. These should be in-cluded in the battery training schedule, closelyallied with the training in service of the gunoutlined in paragraph 7 of this appendix.Approximately 8 hours should be devoted to thisinstruction.
e. Additional service of the gun training maybe performed during battery training exercises.
176
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Section III. TESTS FOR QUALIFICATION OF GUNNERS
8. PURPOSE AND SCOPE
This section prescribes the tests to be given inthe qualification of gunners. The purposes of thetests are twofold:
a. To provide a means of determining the rela-tive proficiency of the individual artillery soldierin the performance of the duties of the gunner,105-mm howitzer M2 and modifications. The testsiwill not be a basis for determining the relativeproficiency of batteries or higher units.
b. To serve as an adjunct to training.
9. GENERAL INSTRUCTIONS
a. Standards of Precision. The candidate willbe required to perform the tests in accordancewith the standards listed below:
(1) Scale settings must be exact and match-ing indexes must be brought into co-incidence.
(2) Level bubbles must be exactly centered.(3) The vertical hair in the reticle of the
panoramic telescope must be alined onthe left edge of the aiming post or onexactly the same part of the aimingpoint or target each time the gun is laid.
(4) Final motions of azimuth and elevationsetting knobs, as well as traversing andelevating handwheels, must be made in
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the appropriate direction. For elevating,the final motion of the handwheel shouldbe in the direction of the more difficultmovement. Final motion for traversingis from left to right. Final movement ofthe vertical hair of the telescope is fromleft to right.
b. Assistance. The candidate will receive nounauthorized assistance. Each candidate mayselect authorized assistants as indicated in thetests. In the event a candidate fails any testbecause of the fault of the examiner or anyassistant, the test will be disregarded, and thecandidate will be given another test of the samenature.
c. Time. The time for any test will be the timefrom the last word of the command to the lastword of the candidate's report. The candidatemay begin any test after the first word of thefirst command.
d. Scoring. Scoring will be conducted in accord-ance with the two subparagraphs Penalties andCredit under each subject. If a test is performedcorrectly, credit will be given in accordance withthe subparagraph Credit under each subject. Nocredit will be allowed if conditions exist as speci-fied in the subparagraphs headed Penalties.
e. Preparation for Tests. The gun will be pre-pared for action and the candidate posted at theproper position corresponding to the test being
181
conducted or as indicated in the subparagraphsentitled "Special instructions." The examiner willinsure that the candidate understands the re-quirements of each test and will require the can-didate to report "I am ready," before each test.
f. Qualification Scores. Minimum scores re-quired for qualification in the courses are asfollows:
Individual Classification Points
Expert gunner .......................... 90First-class gunner ....................... 80Second-class gunner ...................... 70
10. OUTLINE OF TESTS
Para- Number Points Maximumgraph Subject of each credit
number tests
11 Direct laying, pano- 4 2 8ramic telescope.
12 Direct laying, elbow 4 2 8telescope.
13 Indirect laying, de- 18 2 36flection only.
14 Laying for elevation 3 2 6with range quad-rant.
15 Laying for elevation 3 2 6with gunner'squadrant.
16 Displacement correc- 2 - 4tion.
Part I ........ (1) 3 (3)Part II ....... (1) 1 (1)
182
Para- Number Magraph Subject of Points aximum
number tests each credit
17 .. Measuring site to the 1 4 4mask.
18 . Measuring elevation. 1 4 419.. Measuring deflection. 1 4 420 . Tests and adjustment 6 - 10
of sighting and firecontrol equipment.
Tests 1, 3, 4, and (4) 2 (8)5.
Tests 2 and 6 .... (2) 1 (2)21 .. Materiel ........... 3 - 10
Tests 1 and 2... (2) 3 (6)Test 3 ........ (1) 4 (4)
Total credit ........................... 100
11. DIRECT LAYING, PANORAMIC TELESCOPE
a. Scope of Tests.
(1) Four tests (two groups of two testseach) will be conducted in which thecondidate will be required to executecommands similar to those given in cbelow.
(2) Tests 1 and 2 (and tests 3 and 4) willbe executed as one series of commands.
(3) The candidate will be tested in the dutiesof the gunner, using the one-man, one-sight system.
183
Security Information
b. Special Instructions.
(1) A stationary target will be placed ap-proximately 600 yards from the gun.
(2) The fixed azimuth scale and micrometerscale will be set at zero, and indexes ontelescope mount will be matched.
(3) The candidate will be posted as the gun-ner.
(4) The gun will be pointed so that-(a) A shift of approximately 100 mils
will be required for tests 1 and 3.(b) It will not be necessary to shift the
trails for any of the four tests.
(5) Laying at the termination of tests 1and 3 will not be disturbed prior tobeginning tests 2 and 4.
(6) The examiner will announce the assumeddirection of the movement of the targetat the beginning of tests 1 and 3. Theassumed direction of the movement ofthe target in test 3 will be opposite tothat in test 1.
c. Outline of Tests.
Test Examiner commands Action of candidatenumber (for example) Action of candidate
1 and TARGET, THAT Traverses gun until3. TANK; LEAD 5, proper lead has been
RANGE 600. set.
184
Test Examiner commandsnumber (for example) Action of candidate
Places proper range lineof reticle on the cen-ter of the visible massof the target.
Centers cross-level bub-ble.
Gives the command,FIRE, when readyand steps clear.
2 and RIGHT (LEFT) 10, Same as test 1 above.4. 1 ADD (DROP) 200. Same as test 1 above.4. ADD (DROP) 200.
d. Penalties. No credit will be allowed if, aftereach test-
(1) The azimuth scale has been moved fromzero.
(2) The indexes on the azimuth micrometerhave been moved from zero.
(3) The indexes on the telescope mount arenot in coincidence.
(4) The lead in mils is not set properly.(5) The proper range line of the reticle is
not on the center of the visible mass ofthe target.
e. Credit.Time in seconds, exactly or less than.. 4 42/, 5Credit ............................ 2.0 1.5 1.0
185
12. DIRECT LAYING, ELBOW TELESCOPE
a. Scope of Tests.(1) Four tests (two groups of two tests
each) will be conducted in which thecandidate will be required to executecommands similar to those given in cbelow.
(2) Tests 1 and 2 (and tests 3 and 4) willbe executed as one series of commands.
(3) The candidate will be tested in the dutiesof No. 1 cannoneer, using the two-man,two-sight system.
b. Special Instructions.(1) A stationary target will be placed ap-
proximately 600 yards from the gun.(2) For tests 1 and 3 the field of view of
the telescope will be placed on the target,with the correct range line more than100 yards off the target.
(3) The laying of the gun will not be dis-turbed after tests 1 and 3.
c. Outline of Tests.Test Examiner commands
number (for example) Action of candidate
1 and TARGET, THAT Places proper reticle3. TANK; RANGE line for announced
500. range of the centerof the visible mass ofthe target.
Calls "Set' and stepsclear.
186
I ion
Test Examiner commandsnumber (for example) Action of candidate
2 and ADD (DROP) 400. Same as test 1 above.4.
d. Penalties. No credit will be allowed if, aftereach test-Z-
(1) The correct range line is not onthe cen-ter of the visible mass of the target.
(2) The range lines of the reticle are notapproximately horizontal.,
Time in seconds, exactly or less than. . 1%A 145 2Credit .. . 2.0 1.5 1.0
13. INDIRECT LAYING, DEFLECTION ONLY
a. Scope of Tests. Eighteen tests will be con-ducted in which the candidate will be required toexecute commands similar to those given below.Tests 1 through 4 (and tests 5 through 9, 10through 13, and 14 through 18) will be executedas one series of commands.
b. Special Instructions.(1) Commands will not necessitate shifting
trails.(2) The examiner will select a suitable aim-
ing point and identify it to the candidate.(3) Commands for special corrections will
be given only in the tests indicated inthe examples below.
187
- ni;;ton
(4) The command for new deflections foreach test will be within the followingprescribed limits:
Maximum MinimumTest number change change
(mils) (mils)
2 and 11 ......... ... 180 1403 and 12 ...................... 90 704 and 13 ...................... 40 207 and 16 ................ ..... 100 608 and 17 .................. ... 50 309 and 18 ...................... 20 10
(5) The gun will be laid with correct settingsat the conclusion of each test before pro-ceeding with the next test.
(6) Aiming posts will be set out at pre-scribed deflection and distances for thesetests.
(7) The examiner will designate the sectionnumber of the gun to be used. The ex-aminer will announce special correctionsin deflection to be applied by the can-didate.
c. Outline of Tests.
Test Examiner commandsnumber (for example) Action of candidate
1 and SPECIAL CORREC- Sets deflection and10. TIONS, DEFLEC- applies special correc-
TION 2890, NO. 1 tion.LEFT 7.
188
~~~~ o~~in_
Test Examiner commandsnumber (for example) Action of candidate
Centers cross- and lon-gitudinal-level bub-bles.
Traverses gun untilvertical hair is on leftedge of aiming posts.
Checks centering ofbubbles.
Re-lays if necessary.
Calls "Ready" and stesclear.
2 and DEFLECTION 2760. Sets deflection change.11. Leaves correction on
gunner's aid.
Lays on aiming posts.
Checks centering ofbubbles.
Re-lays if necessary.
Calls "Ready" and stepsclear.
3 and DEFLECTION 2835. Same as test 2 above.12.
4 and NO. 1, RIGHT 4..... Same as test 2 above,13.' but changes gunner's
aid to right 4 andresets deflection 2835opposite index.
213618°--52-13
189
Test Examiner commandsnumber (for example) Action of candidate
At conclusion of test Gunner moves gunner's4 (13) give CEASE aid to zero.FIRE, END OFMISSION. (Notime considered forthis operation).
5 and AIMING POINT, Refers telescope to14. CHURCH STEE- church steeple.
PLE, REFER. Reads deflection andcalls "No. 1, Deflec-tion (so much)."
6 and DEFLECTION 2800, Slips the slipping azi-15. REFER. muth micrometer
scale to zero.Slips the slipping azi-
muth scale to 2800.Verifies that vertical
reticle is on churchsteeple.
Calls "No. 1, Deflection2800."
Steps clear.
7 and SPECIAL CORREC- Same as test 1 above.16. TIONS DEFLEC-
TION 2920 NO. 1,LEFT 7.
8 and DEFLECTION 3040. Same as test 2 above.17.
9 and DEFLECTION 3080. Same as test 2 above.18.
190
d. Penalties.(1) No credit will be allowed if, after each
test-(a) The deflection is set incorrectly.(b) The cross-level or longitudinal-level
bubble is not centered.(c) The vertical hair of the telescope is
not on the aiming point or left edgeof aiming posts, as the case may be.
(2) No credit will be allowed if the lastmotion of the traverse was not made tothe right.
e. Credit.Time in seconds, exactly or less than--
Tests 1, 10, 6, and 15 each ...... 12 13 14Other tests, each ............... 8 9 10
Credit ............................. 2.0 1.5 1.0
14. LAYING FOR ELEVATION WITH RANGEQUADRANT
a. Scope of Tests. Three tests will be conductedin which the candidate will be required to executecommands similar to those given below.
b. Special Instructions.(1) Each test will require a change of set-
tings and the accompanying laying ofthe tube in elevation within the follow-ing limits: Site, 15 to 25 mils; elevation,20 to 40 mils.
(2) Commands for elevation for tests 2 and3 will not be made in multiples of 5 mils.
191
(3) Special corrections for site will be ap-plied by the candidate.
(4) The candidate will be posted as No. 1cannoneer.
c. Outline of Tests.
Test Examiner commands Action of candidatenumber (for example)
1 ... SITE 295, ELEVA- Sets announced site andTION 280. elevation.
Centers cross-level andlongitudinal-levelbubbles.
Calls "Set" and stepsclear.
2 . SITE 320, ELEVA- Same as test 1 above.TION 316.
3 . SPECIAL CORREC- Same as test 1 above.TIONS, SITE 310,NO. 1 UP 2, ELE-VATION 323.
d. Penalties.(1) No credit will be allowed if, after each
test-(a) The site or elevation is not set
accurately.(b) The cross-level or longitudinal-level
bubble is not centered.(2) No credit will be allowed if the last
movement of the tube was not in thedirection in which it is most difficult toturn the elevating handwheel.
192
e. Credit.Time in seconds, exactly or less than.. 63/ q37% 83/5Credit ............................. 2.0 1.5 1.0
15. LAYING FOR ELEVATION WITH GUNNER'SQUADRANT
a. Scope of Tests. Three tests will be conductedin which the candidate will be required to executecommands similar to those given below.
b. Special Instructions.(1) The gunner's quadrant will be set at
zero for the first test.(2) Each succeeding test will require a
change of quadrant elevation settingwithin the limits of 30 to 60 mils.
(3) The candidate will be posted to the leftof and facing the breech, with the gun-ner's quadrant in his hand.
(4) An assistant, selected by the candidate,will be posted to the right of the breechto operate the elevating handwheel.
c. Outline of Tests.
Test Examiner commandsnumber (for example) Action of candidate
1 .. QUADRANT 180.... Sets quadrant elevationon gunner's quadrant.Seats quadrant.
Has assistant elevate ordepress the tube untilthe quadrant bubbleis centered.
193
Test Examiner commandsnumber (for example) Action of candidate
Calls "Ready" and waitsfor examiner to verifylaying.
2 ... QUADRANT 240.... Same as test 1 above.
3 . QUADRANT 205 ... Same as test 1 above.
d. Penalties.(1) No credit will be allowed if, after each
test-(a) The quadrant elevation is set incor-
rectly.(b) The quadrant is not properly seated.(c) The quadrant bubble is not properly
centered.(2) No credit will be allowed if the last
movement of the tube was not in thedirection in which it is most difficult toturn the elevating handwheel.
e. Credit.Time in seconds, exactly or less than. . 6 6% 7Credit ....... . 2.0 1.5 1.0
16. DISPLACEMENT CORRECTION
a. Scope of Test. One test, consisting of twoparts, will be conducted in which the candidatewill be required to execute the commands givenbelow.
194
b. Special Instructions.(1) Aiming posts will be set out at the pre-
scribed distances.(2) An assistant, selected by the candidate,
will be stationed close to the far aimingpost.
(3) The examiner will require the candidateto lay the gun on an announced deflec-tion and report "I am ready."
(4) The far post or the gun will then bemoved so that a displacement of 5 to10 mils occurs.
(5) The laying of the gun at the termina-tion of part I will not be disturbed forpart II.
c. Outline of Test.(1) Part I.
Examiner commands Action of candidate
CORRECT FOR DIS- Lays the gun so that the farPLACEMENT. post appears midway between
the near post and the ver-tical cross hair of the tele-scope.
Checks centering of bubbles.
Re-lays if necessary.
Calls "Ready" and steps clear.
195
(2) Part II.
Examiner commands Action of candidate
ALINE AIMING POSTS. Records deflection on shieldand announces "Deflection(so much) recorded."
Directs assistant in aliningaiming posts.
Calls "Ready" and steps clear.
d. Penalties. No credit will be allowed if-(1) Part I.
(a) The far aiming post does not appearmidway between th near post andthe vertical cross hair of the tele-scope.
(b) The cross-level or longitudinal-levelbubble is not centered.
(c) The last motion of traverse was notmade to the right.
(2) Part II.(a) The deflection is other than the
announced deflection..i.) The aiming posts are not properly
alined.(c) The vertical hair of the telescope is
not on the aiming posts.e. Credit.
Part I, time in seconds,exactly or less than ........ 3 31/ 3 4
Credit ...................... 3.0 2.0 1.5 1.0
196
Part II, no time limitCredit ... ................. 1.0
17. MEASURING SITE TO MASK
a. Scope of Test. One test will be conducted inwhich the candidate will be required to executethe command given below.
b. Special Instructions.(1) The gun, prepared for action, will be
placed 200 to 400 yards from a mask ofreasonable height.
(2) The tube will be pointed so that it is100 to 150 mils above the crest and 100to 150 mils right or left of the highestpoint of the crest.
(3) The candidate will take post at the rightrear of the breech.
c. Outline of Test.
Examiner commands Action of candidate
MEASURE SITE TO Sights along lowest element ofMASK. bore and operates elevating
and traversing mechanismuntil line of sight just clearscrest.
Sets angle of site scale at 300,centers longitudinal-levelbubble by turning elevatingknob, and centers cross-levelbubble.
197
s rExaminer commands Action of candidate
Reads elevation from elevationscale and micrometer.
Reports "No. (so-and-so), Siteto mask (so much)."
d. Penalties. No credit will be allowed if-(1) The line of sight along the lowest ele-
ment of the bore does not just clearcrest.
(2) The cross-level or longitudinal-level bub-ble is not properly centered.
(3) The angle of site scale does not read 300.(4) The site is announced incorrectly.(5) The last movement of the tube was not
in the direction in which it is most diffi-cult to turn the elevating handwheel.
e. Credit.Time in seconds, exactly
or less than ............... 11 12 13 14Credit ...................... 4.0 3.0 2.0 1.5
18. MEASURING ELEVATION
a. Scope of Test. One test will be conducted inwhich the candidate will be required to measurethe elevation by means of the gunner's quadrant.
b. Special Instructions. Prior to the test theexaminer will lay the tube at a selected elevation,measure the elevation, and then set the gunner'squadrant at zero.
198
c. Outline of Test.
Examiner commands Action of candidate
MEASURE THE ELE- Places gunner's quadrant onVATION. quadrant seats of the breech
ring.Levels bubble by raising or
lowering the index arm andturning the micrometer knob.
Announces "No. (so-and-so),Elevation (so much)," andhands quadrant to examiner.
d. Penalties. No credit will be allowed if-(1) The quadrant bubble is not centered
when the quadrant is seated properly.(2) The elevation is announced incorrectly.
e. Credit.Time in seconds, exactly or less than.. 8 9% 103/6Credit ................... ....... 4.0 3.0 2.0
19. MEASURING DEFLECTION
a. Scope of Test. One test will be conducted inwhich the candidate will be required to measureand report a deflection in accordance with thecommand given below.
b. Special Instructions.(1) The gun will be laid on aiming posts to
the left front.(2) An aiming point within 200 mils to the
left or right of the aiming posts will be
199
designated by the examiner and identi-fied by the candidate.
c. Outline of Test.
Examiner commands Action of candidate
NUMBER (SO-AND- Centers cross-level and longitu-SO), AIMING POINT, dinal-level bubble.THAT (SO-AND-SO), Refers to aiming point.REFER. Checks centering of bubbles
and re-lays telescope if nec-essary.
Reads deflection and reports,"No. (so-and-so) deflection(so much)" and steps clear.
d. Penalties. No credit will be allowed if--(1) The cross-level or longitudinal-level bub-
ble is not centered properly.(2) The vertical hair of the telescope is not
on the aiming point.(3) The deflection is announced incorrectly.(4) The traversing handwheel is turned.
e. Credit.Time in seconds, exactly
or less than . 5 5%3 6 6%Credit .. : ................. 4.0 3.0 2.0 1.5
20. TEST AND ADJUSTMENT OF SIGHTING AND FIRECONTROL EQUIPMENT
a. Scope of Tests. Six tests will be conductedin which the candidate will be required to dem-onstrate the methods employed in making the
200
prescribed tests and authorized adjustments, ordescribe the action taken (i.e., send to the ord-nance maintenance company) if adjustment isnot authorized to be made by using personnel.
b. Special Instructions.(1) The gun will be prepared for the tests
as indicated in paragraphs 54 and 55 ofthis manual.
(2) The equipment which will be needed forthe tests is listed in paragraph 53 ofthis manual.
(3) The candidate will select an assistantwho will operate the elevating hand-wheel at the direction of the candidateduring tests 1 and 2 and adjust and alinethe testing target at the direction of thecandidate prior to test 5.
(4) The tests will be conducted in the chron-ological sequence indicated in c below.After completion of test 2, the gunner'squadrant used in tests 1 and 2 will beused for test 3, with the proper correc-tion, as determined in test 1, carried onthe quadrant, provided the correctiondoes not exceed 0.4 mil.
(5) Adjustments which the candidate maybe required to accomplish will fall withinthe following limits:(a) Elevation and angle of site scales, not
to exceed one 100-mil graduation.
201
(b) Elevation and angle of site microm-eter scales, not to exceed ten 1-milgraduations.
(c) Rotating head and telescope mountelevation indexes, none.
(d) Rotating head and telescope mountelevation micrometer indexes, not toexceed one-fourth turn.
(e) Panoramic telescope azimuth scale,not to exceed one 100-mil gradua-tion.
(f) Panoramic telescope slipping azi-muth micrometer scale, not to ex-ceed ten 1-mil graduations.
(6) The tube will be leveled at the conclusionof test 2 and will not be disturbed there-after.
c. Outline of Tests.
Testnumber Examiner commands Action of candidate
I ... PERFORM END- Performs test as pre-FOR-END TEST scribed in paragraph
60 of this manual.
ON GUNNER'S Calls "Error (so many)QUADRANT. mils, quadrant serv-
iceable (unservice-able)" and handsquadrant to examinerfor verification.
202
Testnumber Examiner commands Action of candidate
2 .. PERFORM MI- Performs test as pre-C R O M E T E R scribed in paragraphTEST ON GUN- 60 of this manual.
NER'S QUAD- Calls "Quadrant mi-RANT.crometer is (is not)in error."
3 ... TEST TELESCOPE Performs tests andMOUNT. makes adjustments,
if necessary, as pre-scribed in paragraph55 of this manual.
Calls "Cross- (longitu-dinal-) level bub-ble(s) within (with-out) allowable limit."
Caution.-Do not turn cross-leveling or elevation knobsof the telescope mount after this test.
4 .. TEST RANGE Performs tests andQUADRANT. makes adjustments,
if necessary, as pre-scribed in paragraph55 of this manual.
Calls "Ready" and stepsclear.
Note.-Prior to test 5, the cross and longitudinal leveling of the tubeand the panoramic telescope mount will be verified by the examiner, andthe testing target will be alined by the candidate with the help of hisselected assistant as described in paragraph 55 of this manual.
203
Testnumber Examiner commands Action of candidate
5 ... TEST ADJUST- Performs tests andMENT OF PANO- makes adjustments,RAMIC TELE- as prescribed in para-SCOPE. graph 55 of this
manual.
Calls "Ready" and stepsclear.
6 .. TEST ADJUST- Performs test andMENT OF ELBOW makes adjustments,TELESCOPE. as described in para-
graph 55 of thismanual.
Calls "Ready" and stepsclear.
d. Penalties.(1) General. The tests are not essentially
speed tests. The purpose of the pre-scribed time limits is to insure that thecandidate can perform the operationwithout wasted effort.
(2) Test 1. No credit will be allowed if-(a) The bubble of the gunner's quadrant
does not center when verified bythe examiner.
(b) The error (one-half of the amountof the angle which was indicatedwhen the quadrant was first re-versed and the bubble centered by
204
moving the index arm and microm-eter) is announced incorrectly bythe candidate.
(c) The candidate fails to declare thequadrant unserviceable if the error(necessary correction) exceeds 0.4mil, or fails to declare the quadrantserviceable if the error (necessarycorrection) is 0.4 mil or less.
(d) The time to complete the test ex-ceeds 2 minutes.
(3) Test 2. No credit will be allowed if-(a) The procedure is not followed cor-
rectly.(b) The time to complete the test ex-
ceeds 1 minute.(4) Test 3. No credit will be allowed if-
(a) The bubble of the gunner's quadrantis not centered in either direction.
(b) The candidate does not announcecorrectly in regard to the status ofeither the cross-level or the longi-tudinal-level bubble.
(c) The matching indexes on the rockerand actuating arm or those on theelevation knob and shaft are not incoincidence when the adjustmentsare complete.
(d) The time to complete the test andadjustments exceed 4 minutes.
213618°-52-14
205
(5) Test 4. No credit will be allowed if-(a) The elevation micrometer does not
read zero when the elevation scalereads zero.
(b) The angle of site does not read 300when the cross-level and longitudi-nal-level bubbles are centered.
(c) The cross-level or longitudinal-levelbubble is not proprly centered.
'(d) The time to complete the tests andadjustments exceeds 2 minutes.
(6) Test 5. No credit will be allowed if-(a) The candidate fails to make any ad-
justment when such adjustment isindicated.
(b) The rotating head elevation microm-eter indexes are not in coincidence.
(c) The zero line of either the azimuthscale or azimuth scale micrometer isnot in coincidence with its respec-tive index.
(d) The center line of the bore, asviewed through the bore sights, orthe line of sight of the telescope donot fall on their respective sightingpoints on the testing target whenall scales are set at zero.
(e) The time to complete the tests andadjustments exceeds 4 minutes and30 seconds.
206
(7) Test 6. No credit will be allowed if-(a) The reticle is not horizontal.(b) The "N" range line is not in coinci-
dence with the proper sighting lineof the testing target.
(c) The time to complete the test andadjustment exceeds 1 minute.
e. Credit.(1) The candidate will be scored on the gen-
eral merit of his work in addition to thespecific requirements above.
(2) If the tests and adjustments are per-formed correctly within the prescribedtime limit, maximum credit will be givenas follows:
T e st 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Test 2 ....................................... 1Test 3 ....................................... 2Test 4 . . . ...... ....................... 2Test 5 ..................................... 2Test 6 .... .......... . .... .... 1
Total ...................................... 10
21. MATERIEL
a. Scope of Tests. The candidate will be re-quired to perform three tests as outlined below.
b. Special Instructions.(1) Tests 1 and 2. For tests 1 and 2, a paulin
will be placed on the ground for theconvenience of the candidate in laying
207
out the disassembled parts. The candi-date will be allowed to select the toolsand accessories necessary for the per-formance of the tests prior to the startof the tests.
(2) Test 3.(a) A complete set of lubrication equip-
ment authorized for use of batterypersonnel will be made convenientlyavailable on a paulin adjacent to thegun.
(b) Every type of lubricant, in plainlylabeled containers, used on the gunwill be placed conveniently on thepaulin.
c. Outline of Tests.
Testnumber Examiner commands Action of candidate
1 .. D I SASSEMBLE Performs the operationBREECH MECH- as described in TMANISM AND FIR- 9-325, laying theING LOCK. parts on the paulin.
After disassembly,identifies all parts toexaminer.
2 .. A S S E M B L E Performs the operationBREECH MECH- as described in TMANISM AND FIR- 9-325.ING LOCK.
208
Testnumber Examiner commands Action of candidate
3 ... DAILY, WEEKLY, Selects proper lubri-AND MONTHLY cating equipment andLUBRICATION lubricant and showsTEST. how and with which
lubricant each lubri-cation point isserviced. (Actuallubrication is not per-formed.)
d. Penalties.(1) The tests are not essentially speed tests.
The purpose of the maximum time lim-its is to insure that the candidate canperform the operations without wastedeffort.
(2) No credit will be given if the followingtime limits are exceeded:Test 1 ............. ........... 11/2 minutesTest 2 ........................ 3 minutesTest 3 ...................... .. 2 minutes
(3) A penalty of one-half point will beassessed for each component part notcorrectly identified or omitted in test 1.There is no time limit imposed on theidentification of component parts. How-ever, the examiner may reduce the gradeif it becomes obvious that the candidateis not familiar with the nomenclature.
vm _ 209
Security Inormation
e. Credit(1) The candidate will be scored on the gen-
eral merit of his work in addition tothe specific requirements above.
(2) If each test is performed correctly withinthe prescribed time limit, maximumcredit will be given as follows:
Test 1 ........ 3Test 2 ..................... ............ 3Test 3 ..... .......... ........... 4
Total ...................... ......... 10
210
Security
INDEX
Paragraphs Page
Action front ................... 15 19Action, to prepare .............. 17 22Adjustment, disassembly and as- 66 154
sembly.Adjustment of sighting and fire 52, 63 106, 152
control equipment.Qualification tests .......... App. II 172To verify ........... ....... 21 27
Agents, chemical, procedures for 77 161decontaminating.
Aiming circle method, bore sighting 57 129Aiming point:
To indicate to gunner ...... 21 27To set a common deflection. . 22 37
Aiming point, distant ..... 44 92Method of bore sighting ..... 56 128
Aiming points and displacement 44 92corrections.
Aiming posts ................... 44 92'Correction for displacement... 44 92
Qualification tests ....... App. II 172To aline ................... 22 37To set out ................. 27 66
Alinement test (range quadrant) .. 61 146Ammunition (also see Rounds):
Care ...................... 50 104Decontaminating procedure... 77 161Safety precautions ......... 83-86 166Selection .................. 33 73To remove from containers... 28, 29 67, 69To replace ............ ..... 28, 29 67, 69Trajectories ................ 33 73
211
Paragraphs Page
Announced lead, to lay on target.. 35 83Angle of site scale test (range 61 146
quadrant).Angle of site (see Site)Appendix I, References ........ .. . 169
Appendix II, Training ............. 172
Assembly, disassembly and adjust- 66 154ment.
Assign duties with reduced per- 21 27sonnel.
Assistance, gunner's qualification App. II 172tests.
Automotive equipment, decontami- 77 161nating.
Azimuth alinement .............. 62 148Azimuth compensating mechanism 62 148
of telescope mount, test.Azimuth, pivot, alinement test .... 61 146
Basic data, to record ............ 21 27
Basic periodic tests ............. 59 141
Board, section data ............. 51 105
Bore and chamber, to inspect .... 24 56
Bore sighting:Considerations ......... ..... 54 109Equipment ................. 53 106
Methods:Aiming circle .......... 57 129
Distant aiming point ..... 56 128
Standard angle ......... 58 135Testing target ......... 55 115
Bore sights ..... ............... 53 106Breech:
To inspect when open ....... 24 56
To open and close ........... 23 50
212
Paragraphs Page
Bubbles, telescope mount, to center 22 37
Calibration, to apply corrections.. 21 27Cannoneers (also see No._ and 5 5
Section drill).Posts ...................... 9 11To post ................... 9 11
Card, range, preparation ........ 31 72Care and maintenance .......... 65-69 154Care of ammunition ............ 50 104Cartridge case, replace increment 27 66Cease firing .................... 47-48 101Center bubbles, to . ............ 22 37Chamber, to inspect ............. 24 56Change:
A deflection ................ 22 37Fuze of projectiles .......... 25 59In lead .................... 34 80In range ........... ........ 34 80
Changes in data during firing ..... 48 102Charges:
Selection of, for trajectory .. 33 73To prepare ................ 27 66To replace unused .......... 27 66
Check functioning of mat6riel .... 21 27Chemical agents, decontaminating 76-79 161
procedures.Chief of section, duties:
General ................. 5, 69 5, 155In firing direct laying .. '.. 34, 39 80, 87In firing indirect laying ..... 21 27In inspection and maintenance 69 155
After operation ......... 74 159Before operation ........ 70 156During halt ............ 72 158
213
Paragraphs Page
Chief of section, duties-ContinuedIn inspection and maintenance
-ContinuedDuring the march ...... 71 157Prior to and during firing 73 158Weekly ................ 75 160
Circle, aiming, method of bore- 57 129sighting.
Classification, individual, gunners' App. II 172qualification test.
Combination time and superquick 25 59fuzes.
Command:Initial, to give .............. 34 80To fire .................... 35 83
Commands and formations, pre- 8 9liminary.
Commands, subsequent, to give... 34 80Common aiming point, to set de- 22 37
flection.Comparison test ................ 60 142Compensating mechanism, azimuth, 62 148
test.Composititon, gun section ....... 4 5Conduct:
Fire of gun ................ 34 80Prearranged fires ........... 21 27
Conduct of:Fire ....................... 33 73Training ................... App. II 172
Correction (s) :For calibration ............. 21 27Gunner's quadrant .......... 60 142
Correction, displacement:And aiming points ......... 44 92
214
Paragraphs PageCorrection, displacement-Continued
For aiming posts .......... 44 92Qualification tests .......... App. II 172
Corrections, special, to apply:For deflection .............. 22 37For fuze setting ........... 25 59For site ......... .......... 23 50When gunner's quadrant is 21 27
used.Couple .. ,...................... 19 24Coupled (definition) ....... ..... 2 1Cross-level test:
Of range quadrant ......... 61 146Of telescope mount ......... 62 148
Data, basic, to record ........... 21 27Data hoard, section ............ 51' 105Data, changes .................. 48 102Decontaminating procedures for:
Ammunition ............... 77 161Automotive equipment ...... 77 161Instruments ................ 77 161Weapons ................... 77 161
Definitions and terms ........... 2 1Deflection:
Common, to set ............. 22 37Qualification tests:
Indirect laying ......... App. II 172Measuring ............. App. II 172
To apply special corrections.. 22 37To set or change ........... 22 37
Designation of target .......... 34 80Destruction of equipment ........ 80 164
Methods ................... 81 165References ................. 82 165
215
Paragraphs Page
Direct laying:Duties in firing ............. 30 70
One-man, one-sight system 39-42 87Two-man, two-sight system 34-38 80
Qualification tests:Elbow telescope ........ App. II 172Panoramic telescope .... App. II 172
Types, selection of targets... 33 73Direction:
Of fire .................. .. 15 19To lay for ................. 22 37
Disassembly, adjustment, and as- 66 154sembly of weapon.
Dismount, to ............ 12 16Displacement:
Aiming post, to make correc- 22 37tion.
Corrections:And aiming points ..... 44 92For aiming posts ....... 44 92Qualification tests ...... App. II 172
Table, vertical .............. 33 73Distant aiming point ........... 44 92
Method of bore sighting ..... 56 128Drill:
Safety precautions .......... 86 168Driver, duties:
General ................... 5 5In inspection and maintenance:
After operation ........ 74 159Before operation ....... 70 156During halt ........... 72 158During march .......... 71 157Prior to and during firing 73 158Weekly ................ 75 166
216
Paragraphs PageDuties:Assign-when firing with re- 21 27
duced personnel.Firing, direct laying ......... 30 70
Chief of section ........ 30, 34, 39 70, 80, 87Gunner ....... ......... 35, 40 83, 88No. 1 ....... ........... 36, 41 85, 90No. 5 .................. 37 87Remainder of section .... 38, 42 87, 90
Firing, indirect laying:Individuals . ............ 20 26Chief of section ........ 21 27Gunner ................ 22 37No. 1 .................. 23 50No. 2 .................. 24 56No. 3 .................. 25 59No. 4 ........... ....... 26 65No. 5 .................. 27 66No. 6 ........... ....... 28 67No. 7 .................. 29 69
Inspection and maintenance:After operation ........ 74 159
Chief of section ..... 74 159Driver ............. 74 159Gunner ............ 74 159No. 1 .............. 74 159No. 2 .............. 74 159No. 3 .............. 74 159No. 4 .............. 74 159No. 5 ......... .... 74 159Nos. 6 and 7 ....... 74 159
Before operation ....... 70 156Chief of section ..... 70 156Driver ....... ..... 70 156Gunner ............. 70 156
217
Sea
Paragraphs Page
Duties-ContinuedInspection and Mantenance-
ContinuedBefore operation-Continued
No. 1 .............. 70 156No. 2 ............. 70 156No. 3 .............. 70 156No. 4 ........ 70 156No. 5 .............. 70 156Nos. 6 and 7 ....... 70 156
During halt ............ 72 158Chief of section ..... 72 158Driver ............. 72 158Gunner ............ 72 158No. 1 .............. 72 158No. 2 .............. 72 158Nos. 3-7 ........... 72 158
During the march ...... 71 157Chief of section .... 71 157Gunner ............ 71 157Driver ............. 71 157Nos. 1-7 ........... 71 157
Weekly ................ 75 160Chief of section .... 75 160Driver ........... .. 75 160Gunner ...... ...... 75 160Nos. 1-5 ........... 75 160Nos. 6 and 7 ........ 75 160
Movement of gun by hand .... 16 20Preparation for action ...... 17 22
Preparation for travel ...... 18 23
Duties of personnel, general ..... 5 5
Effects of various ammunition .... 33 73Elbow telescope:
Care and maintenance ....... 70, 73, 74 156, 158, 159
218
Paragraphs PageElbow telescope-Continued
Qualification test, direct laying App. II 172Test and adjustment ...... .. 55 115Use ....................... 30, 36 70, 85
Elevation:To call out announced ...... 24 56To lay for ................. 23 50To lay for, with quadrant... 21 27To measure ......... ....... 21 27To set ................... .. 23 50
Elevation, qualification tests:Laying for, with:
Gunner's quadrant ...... App. II 172Range quadrant . ...... App. II 172
Measuring ................. App. II 172Elevation, tests and adjustments:
Knob ....... ............... 55 115Scales ..... ................ 55 115
Emplacement of gun, preparation. 45 97End-for-end test ............... . 60 142Equipment:
Automotive, procedures for 77 161decontaminating.
Bore sighting .............. 53 106Destruction of .............. 80 164Sighting (See Sighting and
fire control equipment.)Errors (See Mistakes.)Estimate range to target, to ..... 34 80Executive, battery:
Inspections by .............. 69 155
Fall out ....................... 13 17Field of fire ................... 32 73
219
S- .Fire: Paragraphs Page
Conduct of ........... ..... 33 73
Field of ......... .......... 32 73
Gun ..... .................. 23 50
Method of ............ ..... 34 80
To command ......... ...... 35 83
To conduct ............ ..... 34 80
To indicate gun ready, to .... 21 27
To the front ............... 15 19
Fire commands, to follow ....... 21 27
Fire control and sighting equip-ment (See Sighting.)
Fires, prearranged, to conduct .... 21 27
Firing:Cease ............ .......... 47, 48 101,102
Changes in data during ..... 48 102
Duties in (also see Duties):Direct laying ........ ... 30-42 70
Indirect laying ......... 20-29 26
With reduced personnel ..... 21 27
Firing and drill, safety precau- 86 168
tions.Firing position, placing ......... 14, 17 18, 22
Form the section .... ........... 8, 9 9, 11
Formations and commands, prelim- 8 9
inary.Formations, section ............. 8 9
Front (definition) .............. 2 1
Front, to fire to ......... ....... 15 19
Functioning of mat6riel, to observe 21 27
and check.Fuze, to set:
Quick, superquick and delay.. 25 59
Time and superquick ........ 25 59
Time using fuze setter ...... 25 59
V T ........................ 25 59
220
Paragraphs Page
Fuze or change fuze of projectile 25 59Fuze setter:
M14 .................... 25 59Setting fuzes with . 25 59
M22 or M23 ............... 25 59Setting fuzes with ...... 25 59
To set ..................... 25 59Tests ................... ... 64 152
Give commands:Initial ............... ...... 34 80Subsequent, based on effect... 34 80
Gun:Definition .................. 2 1Movement by hand ......... 16 20Placing in firing position .... 14, 17 18, 22Placing in travel position 18 23
(march order).Preparation for emplacement. 45 97To apply special corrections 25 59
to fuze settings.To conduct fire ............. 34 80To fire .................... 23 50To indicate when ready to fire 21 27To lay for direction ........ 22 37To load ................... 24 56To refer .................. 22 37To unload .................. 23, 49 50, 102
Gun section, composition ........ 4 5Gun uncoupled, coupled, section 9 11
formation.Gunner duties:
General .................... 5 5In firing:
Direct laying . .......... 35, 40 83, 882136180-52--15
221
Paragraphs Page
Gunner Duties-ContinuedIn firing-Continued
Indirect laying ......... 22 37In inspection and maintenance:
After operation ........ 74 159Before operation ....... 70 156During halt ............ 72 158During the march ...... 71 157Prior to and during firing. 73 158Weekly ................ 75 161
Gunner's quadrant:Test:
Comparison test ........ 60 142End-for-end test ........ 60 142Micrometer test ......... 60 142
Use:To apply special correc-
tions to .............. 21 27To lay for elevation with. 21 27Qualification tests, laying. App. II 172
Gunner's qualification test (SeeTests.)
Halt, duties in inspection during.. 72 158Howitzer (See Mat6riel.)
Identify the target ........... .. 34 80Incidents, unusual, to report ..... 21 27Increments, replace in cartridge 27 66
case.Indirect laying:
Qualification tests, deflection App. II 172only.
Duties in firing (also see 20-29 26Duties).
222
Paragraphs PageIndividual:
Duties ........... .......... 20 26Qualification tests:
Classification .......... . App. II 172Training .............. . App. II 172
Inspect the chamber and bore .... 24 56Inspection and maintenance ..... 68-75 155
After operation ............ 74 159Before operation . ......... 70 156During halt ............... . 72 158During march .............. 71 157Prior to and during firing ... 73 158W eekly .................... 75 161
Inspection and maintenance, re- 69 155sponsibilities.
Battery and higher com- 69 155manders.
Instructions, section drill ........ 7 7Instruments, procedures for decon- 77 161
taminating.
Lay:For elevation .............. 23 35For range ................. 36, 40 85, 88On the target ........... ... 35 83
Laying:For direction .............. 22 34Precision in ................ 43 91Qualification tests:
Deflection only ......... App. II 172Elbow telescope ........ App. II 172For elevation with gun- App. II 172
ner's quadrant.For elevation with range App. II 172
quadrant.
223
Paragraphs Page
Laying, direct (also see Duties).. 30-42 70One-man, one-sight system... 39-42 87Two-man, two-sight system... 34-38 80Type and selection of targets. 33 73
Laying, indirect (also see Duties). 20-29 26
Lead .......................... 34, 39 80, 87Change in .................. 34 80
To determine .............. 34 80To lay with ................ 35, 40 83, 88
Left (definition) ........... .... 2 1
Left trail, shift ................ 24, 28 56, 67
Level the bubbles ............... 22, 23 37, 50Level trunnions (See Trunnions.)List of duties (See Duties.)Load the gun ............... .. 24 56
Maintenance (also see Inspection 68 155
and maintenance.)March, inspection during ........ 71 157
March order .................... 18 23
Mask, to measure site .......... 21 27
Qualification test ........... App. II 172
Mat6riel:Care and maintenance ...... 68-69 155
Destruction ................ 80 164
Observe functioning ........ 21 27Qualification tests .......... App. II 172
Measure:Elevation .................. 21 27
Qualification tests ...... App. II 172
Site to mask ............... 21 27Qualification tests ...... App. II 172
Method of fire .................. 34 80Methods:
Bore sighting .............. 54 109
224
Paragraphs PageMethods-Continued
Bore sighting-ContinuedAiming circle ........... 57 129Distant aiming point .... 56 128Standard angle ...... ... 58 135Testing target .......... 55 115
Destructibn of equipment .... 81 165Misfires, safety precautions for... 85 166Mistakes, report ................ 21 27Micrometer test ............... .. 60 142Minimum training schedule ...... App. II 172Mount, telescope:
Cross-level test ............. 62 148To center bubbles on ........ 22 37
Movement of gun by hand ....... 16 20
No. 1 cannoneer, duties:General. 5 5In direct laying:
One-man, one-sight system 41 90Two-man, two-sight system 36 85
In indirect laying .......... 23 50In inspection and maintenance:
After operation ........ 74 159Before operation ........ 70 156During halt ............ 72 158During the march ....... 71 157Prior to and during firing 73 158Weekly ............. ... 75 160
No. 2 cannoneer, duties:General .................... 5 5In direct laying ........... 38, 42 87, 90In indirect laying ........... 24 50In inspection and maintenance:
After operation ...... . 74 159
225
Paraxaphs Page
No. 2 cannoneer, duties-ContinuedIn inspection and maintenance
-ContinuedBefore operation ........ 70 156During halt ............ 72- 158During the march ...... 71 157Prior to and during firing. 73' 158Weekly ................ 75 160
No. 3 cannoneer, duties:General .................... 5 5
In direct laying ............ 38, 42 87, 90
In indirect laying ........... 25 59
In inspection and maintenance:After operation ........ 74 159Before operation ........ 70 156During halt ............ 72 158During the march ...... 71 157Prior to and during firing. 73 158Weekly ................ 75 160
No. 4 cannoneer, duties:General .................... 5 5
In direct laying ............ 38, 42 87, 90
In indirect laying ........... 26 65
In inspection and maintenance:After operation ........ 74 159
Before operation ........ 70 156
During halt ............ 72 158
During the march ...... 71 157
Prior to and during firing. 73 158
Weekly .......... ...... 75 160
No. 5 cannoneer, duties:General .................... 5 5
In direct laying ............ 37, 42 87, 90
In indirect laying ........... 27 66
226
Sec _i
Paragraphs PageNo. 5 cannoneer, duties-Continued
In inspection and maintenance:After operation ........ 74 159Before operation ........ 70 156During halt ............ 72 158During the march ...... 71 157Prior to and during firing. 73 158W eekly ................ 75 160
No. 6 cannoneer, duties:General. .... ............. 5 5In direct laying ............ 38, 42 87, 90In indirect laying ......... 28 67In inspection and maintenance:
After operation ... 74 159Before operation 70 156During halt ............ 72 158During the march ..... 71 157Prior to and during firing. 73 158Weekly ................ 75 160
No. 7 cannoneer, duties:General..... .............. 5 5In direct laying ............ 38, 42 87, 90In indirect laying ........... 29 69In inspection and maintenance:
After operation ..... 74 159Before operation ........ 70 156During halt ............ 72 158During the march .... 71 157Prior to and during firing 73 · 158W eekly ................ 75 160
Objective:Section drill ................ 6 7Training A..... ......... App. II 172
a 227
s
Paragraphs Page
One-man, one-sight system, direct 39-42 87
laying.Outline, qualification tests ....... App. II 172
Panoramic telescope:Care and maintenance ...... 70, 73, 74 156, 158, 159
Direct laying ............... 35 83
Qualification tests ...... App. II '172
Indirect laying ....... ...... 22 37
Qualification tests ...... App. II 172
Tests and adjustment ....... 55 115
Panoramic telescope mount, test.. 62 148
Periodic tests, basic ............. . 59 141
Periods, individual training..... App. II 172
Personnel:General duties .............. 5 5
To assign duties when reduced. 21 27
Pits:Recoil ..................... 45 97
Spade .................... 45 97
Pivot azimuth alinement test ..... 61 146
Pivot vertical alinement test ..... 61 146
Placing gun in position:Firing ...... .. ............ 14, 17 18, 22
Preparaton for ............. 45 97
Traveling (march order) .... 18 23
Plumb line .... ................. 53 106
Point, aiming:To indicate to gunner ...... . 21 27
To set a common deflection on. 22 37
Point, aiming, distant ....... .... 44 92
Method of bore sighting ..... 56 128
Points, aiming and displacement 44 92
corrections.
228
Paragraphs PagePosts, aiming .................. 44 92
Correction for displacement.. 44 92Qualification tests ...... App. II 172To make ............... 22 37
To aline ...... ............. 22 37To set out ................. 27 66
Posts of:Cannoneers ................ 9 11
Gun coupled ........... 9 11Gun prepared for action. 9 11Gun uncoupled ......... 9 11To change ............. 10 14
Powder charge (See Charge.)Prearranged fires, to conduct .... 21 27Precautions, safety:
Ammunition ............... . 84 166Drill and firing ........... 86 168Misfires .................... 85 167
Precision:In laying ....... ........... 43 91Standards, qualification tests. App. II 172
Preliminary commands and forma- 8 9tions.
Preparation:For gunners' qualification tests App. II 172Of a range card ............ 31 72Of position ................ 45 97
Prepare:Charges ................... 27 66For action ................. 17 22
Preparing charges, to assist ..... 28, 29 67, 69Prime movers:
Care and maintenance ...... 69, 70, 155, 156,74, 75 159, 160
To uncouple ................ 14 18
229
Procedures for decontamination.. 77 161
Projectile, to fuze .............. 25 59
Quadrant, range (See Range quad-rant.)
Qualification of gunners (See
Tests.)Qualification scores ............. App. II 172
Rammer:To unload with ...... ....... 49 102
To use ..................... 23 50
Range ......................... 34 80
Change in ................. 34 80
To estimate to target ....... 34 80
To lay for .......... ....... 36, 40 85, 88
Selection for trajectory ..... 33 73
Range card .... ................ 31 72
Range quadrant:Tests:
Angle of site scale ...... 61 146
Comparison ... ......... 61 146
Cross-level .. ........... 61 146
Pivot azimuth alinement. 61 146
Pivot vertical alinement.. 61 146
Use:Laying for elevation ..... 23 50
Qualification tests... App. II 172
Ready, to call ........ .......... 22 37
Recoil pits ..................... 45 97
Record basic data ........ ....... 21 27
Records ........................ 67 154
Reduced personnel, to assign duties. 21 27
Refer the gun ........... ...... 22 37
230
Paragraphs PageReferences:
Appendix I ....... ......... ... 169Decontamination ............ 79 163Destruction of equipment 82 165G en eral .................... 4
Remainder of section, duties ...... 38, 42 87, 90Remove ammunition from con- 28, 29 67, 69
tainers.Replace:
Ammunition, unused........ 28, 29 67, 69Increments. 27 66
Report mistakes ......... ....... 21 27Responsibilities in maintenance:
Battery and higher com- 69 155manders.
Chief of section ....... 69 155Executive .6...... . ....... 69 155
Right (definition) .............. 2 1Right trail, shift .......... ..... 25, 29 25, 69Rounds (also see Ammunition):
Replace increments in ...... 27 66To call out number of ...... 24 56
Safety precautions ..... ........ . .83 166Ammunition . ............... 84 166Drill and firing ............ . 85 167M isfires .................... 86 168
Scales, test and adjustment:Angle of site .............. 55 115Elevation ................. 55 115Time ...................... 64 152
Schedule, minimum training ..... App. II 172Scores, qualification tests ........ App. II 172
231
Paragraphs Page
Section:Composition ..... .......... 4 5
Definition .................. 2 1
Duties (See Duties.)To form ................... 8 9
To mount and dismount ..... 11, 12 14, 16
Section data board ....... ...... 51 105
Select the target, to ............ 34 80
Set, to:Deflection ... ............... 22 37
Elevation .. ................ 23 50
Fuzes ....... .............. 25 59
Fuze setter ....... ........ 25 59
Site ........ .............. 23 50
Set, to call ... ............ .... 23 50
Set out aiming posts, to ........ . 27 66
Setters, fuze (See Fuze setters.)Shift trails, to:
Left ....................... 24, 28 56, 67
Right .................... 25, 29 59, 69
Sighting and fire control equip-ment:
Bore sighting ...... ........ 53 106
Care and maintenance ...... 70, 72, 156, 158,73,74 158,159
Decontamination .... ........ 77 161
Tests and adjustments ... 52, 64 106, 152
To verify adjustment of ..... 21 27
Qualification tests ...... App. II 172
Site:To apply special correction. 23 50
To mask .................. . 21 27
Qualification tests ...... App. II 172
To set ............. ........ 23 50
232
Paragraphs PageSite, test and adjustment ........ 55 115Spade pits ............... ...... 45 97Special corrections, to apply:
Deflection ... ............... 22 37Site ....................... 23 50Fuze settings .. '.... ... 25 59Gunner's quadrant ... 21 27
Standards:Of precision ... .......... App. 11 172To be attained .............. App. II 172
Subsequent commands, based on 34 80effect.
'Superquick and time fuzes ..... 25 59System, direct laying:
One-man, one-sight ....... 39-42 87Two-man, two-sight ...... 34-38 80
Table, displacement, vertical . 33 73Target:
Designation ................ 34 80To identify or select ........ 34 80To estimate range .......... 34 80To lay on and track ........ 35 83Types, selection for direct lay-
ing. 33 73Target, testing (See Testing tar-
get.)Telescope, elbow (See Elbow tele-
scope.)Telescope, panoramic (See Pano-
ramic telescope.)Telescope mount:
Test ....................... 62 148To center bubbles on ......... 22 37
Terms and definitions .......... . 2 1
233
Paragraphs Page
Testing target .................. 53 106
Testing target method ........... 55 115
Tests:Angle of site ............... 55 115
Basic periodic .............. 59 141
Elbow telescope ............. 55 115
Elevating mechanism ....... 55 115
Fuze setter ................ 64 152
Gunner's quadrant .......... 60 142
Panoramic telescope ......... 55 115
Panoramic telescope mount ... 62 148
Range quadrant ...... ..... 61 146
Tests for qualification of gunners App. II 172
Direct laying:Elbow -telescope ......... App. II 172
Panoramic telescope .... App. II 172
Displacement correction ..... App. II 172
Laying for elevation with:Gunner's quadrant ...... App. II 172
Range quadrant ........ App. II 172
Mat6riel ................... App. II 172
Measuring:Deflection .... .......... App. II 172
Elevation .............. App. II 172
Site to mask .......... App. II 172
Sighting and fire control equip- App. II 172
ment.Time, qualification tests ......... App. II 172
Time and superquick fuzes ...... 25 59
Time fuzes, setting .... .......... 25 59
Time scale test ........ ......... 64 152
Track the target ............... 35 83
Trail shifting:Left ....................... 24, 28 56, 67
Right ..................... 25, 29 59, 69
234
Secui n ,n
Paragraphs PageTraining ....................... App. II 172~~~~~~~Training.App. IT 172Conduct . .................. App. II 172Individual periods ...... .... App. II 172Minimum schedule ......... App. II 172Objectives ................ App. If 172Objectives.App. II 172Standards to be attained ..... App. II 172Trajectories ................... 33 73Traveling position, placing in ... 17 22Trunnions:Bore sighting . ....... 54 109Testing telescope mount . .... 62 148Two-man, two-sight system, direct 34,38 80, 86laying.
Uncouple, to .................. 14 18Uncoupled:Definition .................. 2 1Posts and section formation.. 9 11Unload the gun 23, 49 50, 102Use the rammer ................ 23, 49 50, 102
Vertical displacement table 33 73Vertical pivot alinement test ..... 61 146VT fuzes ...................... 25 59
Weapons, decontaminating ...... 77 161Weekly inspection and mainte. 75 160nance, duties.
*U. S. GOVERNMENT PRINTING OFFICE: 1952 - 213618
'f4r 5 235
