.338 Lapua Magnum/RUAG 260gr AP/Horus Vision System

Ultra Long-Range Precision Strike Demonstration by Dr A.R. Krstic, WSD, SSL, DSTO(E) at the Lancelin Naval Training

Area W.A. September 2003

SUMMARY Dr Alexander Krstic (Acting Head Terminal Effects Group-WSD) recently demonstrated the ability to achieve Point of Aim = Point of Impact (POA = POI) precision strikes and terminal effects on a man-sized target at a range of 2,400m using a custom built lightweight .338 Lapua Magnum bolt action rifle loaded with RUAG’s 260gr Armour Piercing ammunition. Also critical to the success of this demonstration was Horus Vision System’s proprietary telescopic sight and hand-held computerised fire-control system. The 2,400m accuracy and terminal effects demonstration was just one component of a special small arms working group/training session conducted at the Lancelin Naval Training Area (LNTA) Western Australia over the period 22 – 30 Sept 03. The implications of this capability demonstration are both overwhelming, and timely. Note: File sizes of images embedded in this document are sufficiently large enough to allow detailed viewing at 500%.

Minute DSTO

Defending Australia and its National Interests

Light Weapon Selection Considerations The types of issues that should be considered when evaluating weapons and ammunition for performance, suitability, or selection include, statement of primary target type, purpose of engagement, desired terminal effects i.e. is there a first-shot kill requirement, maximum and minimum engagement ranges, overall system size and weight, desired firepower i.e. is there a rapid second-shot requirement, recoil, muzzle signature, dispersion, in-flight projectile stability, port pressure profiles for self cycling systems, intervening materiel penetration characteristics, energy deposition profiles for soft-tissue strikes, ergonomics, commercial availability, value for money, the equipment’s ‘black factor’ and so on. The Changing Battle-Space In order to maintain some semblance of ‘ballistic advantage’ and survivability, snipers must be operating from an absolute minimum range of 500 – 600 metres. With about 3.0 kJ of muzzle energy, the 7.62mmx51 NATO cartridge (.308 Win) is barely adequate out to about 800m. By comparison, however, for a system weight of less than or equal to that of most 7.62mm rifles, the .338 Lapua Magnum, with about 7.0 kJ of projectible persuasion, possesses far superior ballistics, and an excellent hit probability under ideal conditions, out to at least 2,000m.

Figure-1: .338 LM ‘Blaser R93 LRS2’ (ca. 4.0kg bare) fitted with Horus Vision Systems Optics.

Comparative Performance of .338 Lapua Magnum with .308 Win (7.62x51mm) Simply put, there is no comparison between the .338 Lapua Magnum and .308 Win (7.62mm NATO) cartridges, for the .338 LM is a whole class above the .308 Win, a point succinctly demonstrated in Table-1 below. For convenience only, Lapua’s 170gr FMJ HPS has been used to represent the .308 Win case, whilst Lapua’s 250gr FMJ LockBase has been used for the .338 Lapua Magnum case.

Cartridge Ammo BC/G1 Range Velocity ToF Energy Bullet Drop RH Spin Drift

(m) (m/s) (s) (J) (m) (m) .308 Win 170gr HPS 0.525 0 780.0 0.00 3,345.3 0.00 0.00 .338 LM 250gr FMJ 0.662 0 900.0 0.00 6,564.1 0.00 0.00 .308 Win 170gr HPS 0.525 1,000 316.6 2.0545 551.2 -14.924 0.3804 .338 LM 250gr FMJ 0.662 1,000 496.7 1.4932 1,999.1 -8.417 0.3071 .308 Win 170gr HPS 0.525 1,400 273.9 3.4201 412.6 -41.142 1.0975 .338 LM 250gr FMJ 0.662 1,400 368.3 2.4276 1,099.3 -21.023 0.7983 .308 Win 170gr HPS 0.525 2,000 213.5 5.9413 250.6 --123.458 3.5642 .338 LM 250gr FMJ 0.662 2,000 285.9 4.3353 662.3 -63.400 2.5072

Table-1: Comparative Ballistics - .338 LM versus .308 Win Time of Flight (ToF) One of the most important ballistic parameters governing hit probability for ultra long-range sniping is time of flight (ToF), for estimation errors in the target’s range, speed/direction, air density (i.e. temperature, pressure and relative humidity), wind speed/direction, muzzle velocity, spin-drift as well as the line of sight’s (LoS) inclination angle, are all minimised by a shorter ToF. Shorter times of flight can be achieved through a combination of higher muzzle velocity, faster rifling twist rate and higher ballistic coefficient (BC/G1 ie, more efficient free flight through the air). For example, the .308 Win 170gr HPS takes 38% more time (slower) to arrive at a 1,000m target than the .338 LM 250gr FMJ. The BC/G1 for the 308 Win 170gr HPS is 26% less efficient than that of the .338 LM 250gr FMJ. This translates directly into increased hit probabilities, better retention of down range velocity, higher impact energy, and better terminal effectiveness at much longer ranges for .338 LM configured rifles. Ultra Long-Range Accuracy with RUAG’s .338 LM 260gr AP Whilst realistic practical engagements would be limited to about 800m, critical accuracy (proportional dispersion) for the .308 Win 170gr HPS is maintained out to about 900m, whereupon the projectile becomes subsonic. Beyond this range, dispersion rapidly expands, and even if a target impact is arbitrarily achieved (the projectile has to land somewhere, after all), the desired soft-tissue terminal effects cannot be assured. Indeed, it is noted from the ballistic modelling in the 1994 ‘Black Report’ (Krstic et al) that a standard Kevlar vest (with no hard armour inserts) will most likely stop an F4 Ball (144gr FMJ) projectile at about 1,200m. In stark contrast, RUAG’s .338 LM 260gr Armour Piercing (tungsten-cobalt) round might possibly be stopped by the same vest at about 2,500m.

Figure-2: RUAG’s .338 Lapua Magnum 260gr Armour Piercing (Tungsten-Cobalt) Projectile. The unique design, forward placement of Cg and extremely high quality build standard, are clearly evident from the sectioned images. Critical accuracy for the .338 LM 250gr FMJ was already suspected of being able to reach out as far as 1,500m, whereupon the projectile becomes subsonic, with associated deterioration of dispersion. Prior to the Sept 03 LNTA training session, the best group achieved at 1,000m from the author’s .338 LM Sako TRG-S had been 5 shots into 4 inches (i.e. less than 0.4 MOA - fired off the ground with the aid of a bipod) under DSTO trials conditions (P&EE Pt Wakefield, 1995). A highlight of the Sept 03 LNTA range activity was a demonstration during which two successive shots landed two inches apart on the designated aim point on a man-sized target at a range of 2,400m. The rifle was a custom built, heavy barrelled .338 Lapua Magnum bolt-action repeater, loaded with RUAG’s 260gr Armour Piercing ammunition. The RUAG 260gr AP round had already been selected prior to the LNTA activity, on the basis of its quality construction and material composition. As can be seen in Figure-2 above, the design is primarily that of a conventional FMJ boat tail, however, its high density AP core is almost wholly located in the forebody of the projectile. This affords a unique (and highly desirable) ballistic characteristic to this projectile, namely that its centre of gravity (Cg) is now located in the forebody, rather than towards the rear of the midsection. This design has reduced the distance (separation) between the centre of pressure (Cp) which is also located in the forebody, and the Cg. The separation (ΔCg -Cp) between these two quantities is referred to as the ‘static margin’ a quantity which can be thought of as the length of the ‘drag-lever’ used by the retardation forces to try to destabilise the projectile, ie, the longer the drag-lever (separation between Cg and Cp), the easier it is for the total drag forces (all of which can be said to be acting at the Cp) to induce an overturning moment on the projectile. .338 Lapua Magnum Hard Target Terminal Effects With the RUAG 260gr AP having only just been retained by half-inch mild steel plates out to 2,000m, it can be expected to easily work its way through the rear face of Level-IV monolithic ceramic body armour panels out to about 1,000m (ie, 0° strike angle with about 3,000 Joules of impact energy). In fact, given that the RUAG 260gr AP round can travel almost 7km at optimum launch elevation, in the absence of any purpose-built body armour, desired soft-tissue terminal effects for ‘unprotected’ human target strikes by this particular projectile can quite reasonably be anticipated all the way out to about 4,000m, if it were to actually hit the target at such a range. Ultra Long-Range Sniping with the Horus Vision System and .338 Lapua Magnum Rifle When a high value target gives a fleeting presentation, the sniper team needs to engage the simplest, fastest and most flexible approach to ensure a cold-barrel first-shot kill, itself a core philosophy of the Horus Vision System. Horus’ hand-held Palm ballistic calculator system models small to medium calibre direct-fire engagements out to a range of 4,000yards, with the ability to compensate for wind-drift, spin-drift and coriolis (where required) on both static and moving target engagements.

Using the Horus hand-held direct fire control system, parameters that define the exact trajectory, including spin-drift, coriolis and bullet drop out to the maximum effective range, are known. Using Horus’ bundled PLRF-15 laser range finder (NV proof variant of the PLRF-10) and Kestrel 4000 ‘Met’ unit, the exact range to target, and atmospheric conditions are known. The Horus H-39 and H-38 telescopic sight reticle planes consist of glass etched graticule patterns in the form of numerically labelled, finely grided meshes. At ultra long-ranges, the projectile’s ToF (ca. 4.5 seconds for the 2.4km shots – enough time for a quick sip of coffee) is such that the firer can actually re-acquire his sight picture well in time to observe his own fall of shot, which as a result of the ballistic calculator, should be exactly on target, or very close by. Horus’ latest Palm based ‘ATrag MP’ software package can store user-defined fire-control details for scores of weapon/ammunition combinations, each of which is instantly retrievable at a moment’s notice. It is quite possible that the sniper’s initial impression of the Horus glass-etched reticle’s finely grided mesh will be that it is far too busy, and that being so fine, it might tend to disappear into the darker shades of the sight picture, not to mention all of the additional training requirements and so on. In reality, however, all Horus Vision Systems Mil-Spec scopes now come with illuminated reticles and parallax adjustment. This arrangement easily accommodates wide variations in ambient light, target colour, shade and texture as well as range. In terms of training investment versus capability enhancement, the Horus Vision System is able to transform an inexperienced shooter into an extremely potent, long-range trigger-man, in a minimal amount of time. With this thought in mind, the implications of the Horus System in the hands of an already proficient shooter becomes an even more interesting proposition. One of the key features of the Horus Vision system now comes into play, for even though the first shot’s POI may possibly have just missed the actual POA, the firer’s original sight picture has been re-established, thereby allowing the exact coordinates of the bullet’s POI on the reticle’s grid pattern to be recorded. In other words, without making any turret adjustments whatsoever, the observed POI grid coordinates now become the ‘corrected’ local crosshairs for the follow-up second shot, which naturally results in a POA = POI, i.e. an extremely rapid second shot kill of the briefly exposed high value target, out to the maximum engagement range. In reality, however, snipers usually work in two-man teams, the first being the trigger-man, the second the observer. The observer’s job usually requires him to use his high magnification spotting scope, laser range finder and ‘met’ device to positively identify and indicate a target, give its range and call the sniper’s telescopic sight turret adjustments (windage, elevation, lead etc). Having confirmed and executed the preparatory instructions of the observer, the sniper then squeezes off the shot. The usual sequence of events would be that the observer then records the fall of shot and indicates either a ‘gunner’s correction’, or exact turret adjustments for the sniper’s rapid follow up shot in the event that a first-shot kill did not occur. With the Horus Vision System on the other hand, the glass-etched finely grided mesh reticle pattern in the 40X Horus Vision spotting telescope is identical to that in the firer’s telescopic sight. In other words, it is as if the observer was in fact the firer, placing his spotting scope’s crosshairs over the same POA used by the trigger-man. At short to intermediate ranges, where the ToF is so small that the firer has no time to re-acquire his original sight picture prior to shot impact, it is up to the observer to record the ‘Horus coordinates’ of the fall of shot (relative to the original Horus POA coordinates), and relay them to the sniper who will then place the local crosshairs at those coordinates in his Horus telescopic sight, over the original POA for the rapid follow up shot.

.338 Lapua Magnum bolt action sniper rifles are now available with system weights less than that of most

.308 Win rifle systems. For example, the Blaser R93 LRS2 (Figure-1 above) uses an ultra lightweight, one-piece synthetic stock with a crisp 3-way adjustable trigger situated below a straight-pull radial expansion locking action backed onto a fluted, high hardness hammer-forged barrel. The barrel and integral scope are rapidly removed as one, via two captive Allen Head bolts. These .338 Lapua Magnum rifles also come with about three times the .308 Win’s range against both hard and soft targets. The .338 LM has been demonstrated to clearly out-group the best .50 Cals at 2,000 yards where it still has more impact energy (terminal effect potential) than most .308 Win rounds have at about 800m.

Weapon Type Ammunition Type Sniper Telescopic Sight

7.62x51mm NATO SR-98 bolt action repeater anti-personnel sniper rifle, 660mm barrel with 1 turn in 250mm twist, 6.4kg empty; Accuracy Int. - UK

170 FMJ HPS B436 LockBase Lapua

Schmidt & Bender 3-12 x 50 1 click = 0.1 Mil = 1cm at 100m 19 Milliradians total elevation

.338 Lapua Magnum TRG-S bolt action repeater ‘modified’ lightweight hunting rifle, 711mm barrel with 1 turn in 229mm twist and 30 MOA nose-down ramped Picatinny rail, Sako - Finland

RUAG 260gr AP RUAG 252 gr FMJ Black Hills 250gr HPBT

Horus 3-17X US Optics glass etched H-39 type graticule with a total of 185 MOA elevation between scope reticle ‘zero’ and base ramp

Table-2: Weapons and ammunition used during the LNTA-03 activity Training Session Activities 20th – 30th Sept 2003 The major purpose of the LNTA component of the training session was to identify the ultra long-range utility of the .338 LM system in conjunction with the Horus Scope and its associated ‘bundle’ of direct fire-control accessories. The next most important aspect was to identify the best balance of accuracy and terminal effectiveness (anti-materiel and anti-personnel) out to the maximum useful range. Serial-1 .338 Lapua Magnum Activities

� Identify max useful range from best .338 LM ammo with complete Horus System

1.0-2.4km accuracy with .338 LM/Horus Vision System – RUAG 260gr AP and Black Hills 250gr HPBT Match ammunition

� Identify potential terminal effects out to max useful range with complete Horus

System

1.0-2.4km terminal effects with .338 LM/Horus Vision System – RUAG 260gr AP and Black Hills 250gr HPBT Match ammunition

Serial-2 .308 Win (7.62x51mm NATO) Activities

� Identify max useful range from best .308 Win ammo with complete Horus System 0.6-1.0km accuracy with .308 Win/Horus Vision System – RUAG 196gr AP and

170gr FMJ HPS � Identify potential terminal effects out to max useful range with complete Horus

System

0.6-1.0km terminal effects with .308 Win/Horus Vision System - RUAG 196gr AP and 170gr FMJ HPS

Figure-3: Deliberately aimed, successive man-sized target strikes at a range of 2,400m from a customised, lightweight .338 LM rifle fitted with Horus Optics, and firing RUAG 260gr AP ammunition Evening Exercises These involved specialised instruction in the interpretation and use of the Horus telescopic sight’s glass etched ‘H-39’ type ultra long-range graticule, the use and programming of Horus’ hand-held ballistic calculator and Kestrel 4000 meteorological units, the combo inclinometer/spirit level, determination of barrel twist rate and best use of the 40X observation telescope with matching graticule pattern. A comprehensive range of ballistic theory lectures, including theoretical determination of ballistic coefficient (BC) (in the field) from known muzzle velocity (MV) and fall of shot, as well as determination of MV from known BC, and fall of shot were also provided. These also included theory considerations and the demystification of Schmidt & Bender’s Mil-type reticled telescopic sights.

The .50 Cal Issue The Barrett M82A1M has significant modifications which afford greater strength than its predecessor which was offered during the first .50 Cal tender trials in late 1998. Hit probability at extended ranges against torso-sized metal targets with the Raufoss MP-NM140 round is essentially equivalent to that of the bolt action AW50. By not having to work the bolt manually, the sniper avoids serious disruption of sight picture and general firing position, thereby allowing fast re-acquisition and rapid follow up shots on briefly exposed, high value targets. Unlike the almost 1.2 metre long, 17.0 kg bolt action AW50, the Barrett M82A1M semi-auto can be broken down into several sub-components for weight and length distribution amongst patrol members. Recommendations Based on the understanding that a .338 LM round with similar ‘explosive’ terminal effects to those of the SR-98’s 130gr Win HP Super-X will be commercially available sometime within the next 3 months, serious consideration should be given to re-configuration of the ADF’s weapons mix by introduction of .338 Lapua Magnum rifles (Germany’s Blaser R93 LRS2 shown in Figure-1 as an indicative example only) using RUAG 260gr AP ammunition as its main operational round, along with an appropriately ‘explosive’ round based on a 200 – 225gr projectile. In light of the overwhelming capability enhancement demonstrated during LNTA Sept 03, serious consideration should also be given to the purchase of Horus Vision Systems’ bundled fire-control capability which is comprised of the Palm hand-held ballistic calculator (for trajectory modelling), the PLRF-15 laser rangefinder (night-vision proof), the Horus 3.8-22 x 58mm (illuminated) telescopic sight (built under contract by US Optics), the Leupold 20-40X observation telescope (with matching Horus graticule), the Kestrel 4000 meteorological unit, the anti-cant device and the analogue inclinometer. Dr Alexander R Krstic Acting Head Terminal Effects Weapons Systems Division, SSL Defence Science & Technology Organisation PO Box 1500 Edinburgh SA Australia 5111 Ph +618 8259 6310 Fx +618 8259 7702 Mbl +61 402 0888 68 alex.krstic@dsto.defence.gov.au 14th November 2003