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GRENADE LAUNCHERS AND THEIR AMMUNITION:

INTERNATIONAL DEVELOPMENTS

© Anthony G Williams

This article is based on various presentations given in 2013-15 and on articles published in Jane's International Defence Review (November

2013) and in Small Arms Defense Journal (Vol.7 No.1) Grenade launchers and their ammunition are currently experiencing the fastest and most dramatic period of development of any small arms. This article will provide a summary of shoulder-fired and crew-served grenade launchers, concentrating on developments in ammunition types. NATO 40mm Systems NATO is currently focused on the 40mm calibre for under-barrel or stand-alone shoulder-fired launchers and also for crew-served automatic launchers. However, while the calibre is standard, there are now four different performance levels to choose from. Two are long-established, dating back to the Vietnam War: the 40mm Low Velocity (or LV) which uses 40 x 46SR (Semi-Rimmed) ammunition in shoulder-fired or underbarrel launchers, and the 40mm High Velocity (or HV), which fires 40 x 53SR rounds from crew-served automatic launchers. 40mm LV ammunition is currently made by about 25 different companies in 18 countries, in a wide range of lethal, less-lethal and other natures. Apart from conventional HE and HEDP these include thermobaric HE, HE Jump (a low-cost airburst, in which a small nose charge fires on impact, kicking the grenade a couple of metres into the air before it explodes), and HE anti-diver, designed to explode underwater. Non-explosive loadings include shot loads, smoke, illuminating and signal flares, a huge range of less-lethal ammunition matching that available in 37mm riot guns and including both impact and chemical types (the latter for non-military use), and even reconnaissance projectiles – the SPARCS from STK has a parachute-borne camera. The universality of the ammunition means that there are numerous stand-alone and underbarrel launchers made to fire it. The M79 was the classic single-barrel stand-alone type but this has largely been replaced

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by underbarrel launchers such as the M203, which is itself being replaced in the US and other armies by more modern underbarrel launchers like the L123A1 and M320 from Heckler & Koch, which can fire a wider range of munitions and can be fitted with a stock and sights for the stand-alone role. When more firepower is required, six-shot revolvers such as the USMC's M32 are also available from several companies, at the cost of significant bulk and weight.

40mm HV ammunition is made by some 15 companies in a dozen countries. It fires grenades which are typically 30 percent heavier than the LV at three times the muzzle velocity, increasing the maximum ballistic range from 400 to over 2000 metres (although the effective maximum is significantly less in both cases). Recoil is several times greater, which means that attempts to design shoulder-fired weapons for this cartridge have so far been unsuccessful, although NORINCO of China recently announced one. The ammunition is therefore used in crew-served, tripod-mounted, belt-fed launchers generally known as automatic grenade launchers or AGLs. The original launcher was the MK19 which is still very much in use, although more recently a wide range of competitors has emerged, most notably the GMG (Grenade Machine Gun) from Heckler & Koch, in service with fifteen countries. There is much less variety than with LV in the types of ammunition

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available, owing to the requirement to fit into the ammunition feed and to develop a certain level of recoil to operate the launcher, so HE/fragmentation or HEDP are the standard natures.

In recent years two new performance levels have been introduced for shoulder-fired launchers. The first of these is the Medium Velocity or MV ammunition, intended to provide a greater effective range than LV plus a larger and more destructive grenade. Cartridge case lengths vary from 46 to 51mm. The first of these were from Martin Electronics (now part of the Chemring Group), with Rheinmetall also developing MV rounds. The heavier grenades fired at a higher muzzle velocity result in a maximum ballistic range in the region of 700-800 metres, and when fired at shorter ranges have a much flatter trajectory and shorter flight time than LV rounds, considerably improving their hit probability. However, the additional recoil can be considerable, especially in lighter weapons, so this ammunition is currently best suited to the solid and heavy six-barrel revolver type launchers; in fact, the Rheinmetall rounds have a modified case rim to prevent their use in unmodified LV launchers. As a result of the recoil problem, some manufacturers, namely Arcus of Bulgaria, STK of Singapore and Rheinmetall again, have introduced what is now usually called Low Velocity Extended Range ammunition (LV-ER), which sits in between the low and medium velocity types and is

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specifically intended for under-barrel or single-barrel launchers. These typically have maximum ballistic ranges of 600+ metres. While the performance of HV and to some extent LV rounds is standardised, that's not the case with MV and LV-ER ammunition, to which different manufacturers have different approaches. The first MV rounds used new grenade designs but Rheinmetall has adopted a simpler solution with their Velan range, which fires their standard HV grenades from a lower-powered cartridge. In contrast, all of the LV-ER makers combine their standard LV grenades with higher-powered cartridges, but the muzzle velocity and range vary.

The table above summarises some typical characteristics of 40mm ammunition, but it should be borne in mind that the characteristics of MV and LV-ER ammunition do vary. It should be noted that the weights quoted here are for the grenades only, not the complete rounds, and that ranges are maximum ballistic figures; the effective ranges against area targets would be around two-thirds of these figures, against point targets less than half. The two columns on the right indicate the relative recoil impulse of the four types, and their free recoil energy if the ammunition was fired in guns of the same type and weight. So far, there seems to have been much interest but few contracts for MV and LV-ER ammunition, but that may change in the future.

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Other Grenade Systems Beyond NATO, the main supplier of grenade launchers is Russia, although China is catching up. The Russian equivalent to the NATO low-velocity round is the VOG-25 series, another 40mm of similar performance, but differing technically in being caseless - the propellant is contained within a small element attached to the back of the grenade that travels with it. As with the NATO LV, a very wide range of munitions is available for it. The muzzle-loading GP-25 and GP-30 are the standard launchers, but there are also six-shot revolvers and an interesting three shot Arcus repeater with the tubular magazine in the shoulder stock.

The Russian equivalent to the high-velocity round is the VOG-17 series which uses a conventional cartridge but differs in being of only 30mm calibre. However, the projectile is unusually long and similar in weight to the NATO 40mm HV. The maximum ballistic range was originally a few hundred metres less than the NATO HV, but recent ammunition developments have seen this increase to more than 2,000 metres. Apart from the automatic belt-fed AGS-17 and AGS-30 launchers from Russia, Slovakia offers a shoulder-fired magazine-fed bipod-mounted weapon using this 30 x 29B (Belted) round, the RAG-30, which offers an interesting level of portable firepower as it weighs only 12 kg (26½ lbs).

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Russia also produces some oddities, including two different 30mm captive-piston under-barrel systems for special forces which are virtually silent when fired. The BS-1 uses a conventional blank cartridge to drive a captive piston forwards in the launcher (the trapped gases need to be bled off before the launcher can be reloaded). The BMYa-31 uses a special blank round that incorporates its own captive piston (the blank containing the sealed-in gases can be ejected and the launcher reloaded immediately). Maximum ranges are 300-400 metres. Also in use in Russia is the 43mm GM-94 stand-alone launcher that resembles an oversized pump-action shotgun and fires VGM-93 ammunition at ranges of up to 600 metres. The ammunition is mostly less-lethal but includes a thermobaric HE round, presumably for the more emphatic dispersal of rioting crowds. Russia has reportedly introduced into service, apparently for special forces, the 40mm Balkan AGL that fires unique caseless grenades, much bigger and heavier than the VOG-25 series. These rounds weigh 450 g and contain 90g HE which, in conjunction with the 2,500m maximum range, amounts to a better on-paper performance than the NATO AGLs.

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China initially adopted Russian equipment but has now developed its own in 35mm calibre. There are three different, incompatible series of 35mm grenades and associated launchers. Two of them are low-velocity types for underbarrel grenade launchers: the caseless low-velocity 35mm DFS10 round for the army's QLG10 launcher, which is like a slimmed down VOG-25 and has a similar performance, and the Type 91 UBGL firing plastic-cased ammunition, which is mainly used with less-lethal grenades for riot control.

The best-known Chinese grenade is the conventional 35 x 32SR high-velocity DF87 series ammunition which has a ballistic range of 1,750 metres. The HEDP grenade, which is slightly heavier than NATO's 40mm HV, is claimed to penetrate 80mm armour plate as well as having a lethal radius of 11 metres. It is used in a pair of automatic launchers, the belt-fed, tripod mounted QLZ04 which weighs 55 lbs including tripod (about half that of the MK19) and the even lighter, magazine-fed QLZ87 which is available bipod or tripod mounted and weighs only 44 lbs with a tripod, 26½ lbs on a bipod.

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The most interesting weapon using the 35 x 32SR round is the lightweight semi-automatic QLZ87B (now known as QLB06), which has a 1,000m range against area targets and 600m against point targets. This offers a combination of firepower, range and light weight (only 9.1 kg - 20 lbs empty) not approached by anything except the RAG-30. Much is said about achieving "overmatch" over potential opponents, and this weapon provides an example of what that means in portable grenade launchers. The QLZ87 and QLB06 seem to have been widely distributed to third-world countries since they have been spotted in Africa (in Sudan, Chad and Uganda) and the Middle East (in the hands of Syrian insurgents) as well as South America, so NATO troops may well be on the receiving end of their fire in future conflicts.

The table above provides the basic data for the Russian 40mm low-velocity caseless VOG-25, the high-velocity 30mm VOG-17, the Chinese 35mm low-velocity DFS10 and their 35mm high-velocity DF87 series. The recoil figures quoted are calculated on the same basis as for the NATO grenades in the table shown earlier, in which you may recall that the 40mm HV round developed a recoil energy figure of 17.6, significantly greater than either the Russian or Chinese high-velocity rounds, which makes it much more difficult for shoulder-fired launchers

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to be designed around the NATO HV ammunition, although the Chinese have done it, as we shall see. Finally, it is worth mentioning a different approach that is not strictly a grenade launcher but doesn't really fit in anywhere else: the South African Neopup PAW 20 (Personal Assault Weapon). This semi-automatic gun fires standard 20mm cannon shells at subsonic velocity from a small cartridge case and, given its compact dimensions and weight of 5.7 kg (12½ lbs), is claimed to be usable as a personal weapon when firing inert steel slugs, as well as for supporting fire with HEI shells. Effective range is 1,000 metres for area fire, 600m against point targets; at a range of 300m the mid-range trajectory height is 1.2 m (4 feet) compared with 26m (85 feet) for the 40mm LV.

The Future The future of 40mm grenade rounds has been under threat for several years due to the rather protracted development in the USA of two different rounds in 25mm calibre: the 25 x 40B for use in the XM25 self-loading shoulder-fired launcher that has been tested in combat and which the Army plans to introduce into service, plus the 25 x 59B round which was originally conceived for the now-cancelled GD XM307 crew-served belt-fed launcher, but is still being offered as a private venture for the externally powered ATK LW25 Chain Gun. Both of these rounds were designed around a new concept in small arms: a time-fuzed

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airburst HE fragmentation grenade designed to strike at personnel hiding behind walls or in trenches. The fuze is in the middle of the grenade meaning that equal quantities of fragments are hurled to the rear of the burst point as to the front. The launcher requires a sophisticated sighting, fire control and fuze-setting system.

The XM25 has a maximum effective range of 700 metres against area targets or 500m against point targets. The ATK LW25 fires a heavier grenade at a much higher velocity for an effective range of 2,000m (at which distance the mid-range trajectory height is about 100 metres (330 feet, compared with 400m/1,300 feet for the 40mm HV). The LW25 ammunition has also been offered in the XM109 Barrett Payload Rifle, a modified version of their self-loading .50 calibre rifle, but without the airburst facility. Two other shoulder-fired launchers using precision airburst fuzing come from South Korea and China. The Korean K11, which is in service, combines a 20mm grenade launcher with a 5.56mm rifle, so is similar in concept to the abandoned US XM29, although the launcher uses a manually-operated bolt action. It weighs 6.1 kg (13½ lbs) and has a maximum effective range of 500 metres. Little information has been released about the Chinese ZH-05 which has largely featured on internet forums, but it also combines a 20mm grenade launcher with a rifle in

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their standard 5.8mm calibre and looks very similar to the Korean gun. Rather surprisingly the launcher is a single-shot type with no magazine; this does help to keep the empty weight down to a reported 4.26 kg (9.4 lbs: 5.0 kg/11 lbs loaded with a full 5.8mm magazine and a grenade). Effective range is claimed to be 800 metres, achieved at an angle of elevation of 7 degrees, but the grenade is relatively light.

The unique selling point for these new systems – precisely-timed airburst – is already spreading. A similar capability first appeared in four different 40mm high-velocity systems from three different manufacturers: STK, with a fuze-setter fixed to the muzzle (a system based on the Oerlikon AHEAD cannon system); Nammo, with two systems: an inductive fuze setter in the chamber for closed-bolt launchers like the Striker MK47, and a radio-frequency setter, independent of the gun, for open-bolt guns like the HK; and Rheinmetall with an infra-red fuze setter which is also independent of the gun. More recently, 40mm low-velocity systems have also appeared, from IMI of Israel using inductive fuze setting in a modified launcher as part of their MPRS (Multi-Purpose Rifle System), and another from STK using remote fuze setting. Rheinmetall has also announced precision airburst rounds for their Velan medium-velocity system, using the same infra-red fuze setting and grenades as their HV ammunition.

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There do not seem to have been any reports that precision airburst systems are being applied to the Russian 30mm or the Chinese 35mm systems, yet it is surely only a matter of time before they appear. The capabilities of such systems in a portable weapon like the 35mm QLB06 would potentially be impressive. Furthermore, the addition of rangefinding sights would considerably enhance the effectiveness of conventional ammunition. Clearly, the 40mm systems have an advantage over the 25mm of being able to use low-cost ammunition from a wide variety of manufacturers as well as the costly precision airburst grenades. Most low-velocity systems are more flexible than the self-loading XM25 because they can fire a wide range of munitions of different lengths, weights and pressure characteristics. On the other hand, the 25mm systems offer a much better hit probability because their higher muzzle velocity gives them a flatter trajectory and shorter flight time, providing some compensation for their smaller grenades. Perhaps the most interesting Western launcher project is from Rheinmetall, who have developed a recoil buffering system that enables their powerful 40mm medium velocity Velan ammunition to be fired from lightweight guns. This is being applied to two launchers; the single-shot Cerberus in either under-barrel or stand-alone form, and the magazine-fed self-loading Hydra which is expected to weigh around 4 kg (9 lbs)

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and is intended to fire both LV and MV ammunition including precision airburst rounds.

In 2014 NORINCO advertised two new weapons for the export market, both designated LG5s, which appear to be versions of the QLZ87 and QLB06 modified to fire 40mm HV NATO ammunition and reportedly fitted with muzzle-mounted fuze setters for timed airburst. Chinese companies often make products in western calibres for export only, for example the NORINCO LG6, which offers some unique capabilities not available in western systems. It is a multi-shot 40mm LV launcher weighing less than 5 kg (11 lbs), but has a gas-operated selective-fire mechanism capable of emptying the standard five-round magazine in one second. Finally, Metal Storm. Their system of stacking several rounds in one barrel to be fired in sequence is particularly well-suited to the relatively short, wide and low-pressure grenade rounds. It achieves multi-shot capability with far less bulk and weight than either a self-loading or revolver mechanism. Development costs were reduced by reaching an agreement with STK to use their 40mm LV grenades as the basis for the ammunition, which could also provide access to precision airburst technology. However, this company is no longer operating.

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This slide shows a line-up of grenade rounds; most of these are replicas but they give you an idea of how they compare.

The implications Assuming that the current enthusiasm for precision airburst grenade systems continues, what will be the implications of their general use? They necessarily require automatically-adjusting sights linked to a laser rangefinder, a ballistic computer and a fuze setter, and preferably should also have thermal imaging and/or image intensifying capability for 24-hour use. Such sights also provide far greater precision in firing ordinary grenades, so will see increasing use in some form anyway. But while simple rangefinder sights are already in use, the sophisticated systems are currently large, heavy, complex and very expensive. For shoulder-fired launchers, it therefore makes sense to fit these sights to a stand-alone bipod-mounted weapon rather than an underbarrel type to achieve the necessary accuracy (implying a specialist grenadier as a part of the squad); to give it some rapid-fire capability; and to fire long-range ammunition to extract the maximum effectiveness from the costly system.

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In terms of current western projects, that means the XM25 or medium-velocity 40mm ammunition fired from a six-shot revolver or something like the Rheinmetall Hydra. Further up the performance and weight scale, the Chinese have a big performance advantage in starting with the portable QLZ87 and QLB06, at some cost in weight. Afterthought If there is a specialist grenadier in the infantry section/squad, will other riflemen still use UBGLs? Possibly not: there is already resistance to carrying the weight of around 1.5 kg (3.3 lbs) of launcher permanently attached to the rifle, with many US soldiers reportedly preferring to carry it as an additional stand-alone weapon, complete with shoulder stock. This suggests that there might be a case for considering the use of rifle grenades instead. These are less accurate, but typically carry twice the HE load and avoid the need to carry a separate launcher. The French are dedicated users of rifle grenades; shown here is their APAV40 DP in comparison with the M433 HEDP LV grenade. (image from Rama, Wikimedia Commons, Cc-by-sa-2.0-fr)

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