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 caliber for under-barrel or stand-alone shoulder-fired launchers and also for crew-served automatic launchers. However, while the caliber 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 40x46SR (Semi-Rimmed) ammunition in shoulder-fired or underbarrel launchers, and the 40mm High Velocity (or HV), which fires 40x53SR 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 meters 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 The M79 was the classic single-barrel stand-alone type but this has largely been replaced by underbarrel launchers such as the M203, which is itself being replaced in the US and other armies by more modern underbarrel launchers like the M320 from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.

Apparently a version of the QLZ87 chambered for NATO 40mm HV ammunition, shown in a poster display at Eurosatory.

40mm HV ammunition is made by some 15 companies in a dozen countries. It fires grenades that are typically 30 percent heavier than the LV at three times the muzzle velocity, increasing the maximum ballistic range from 400 to over 2,000 meters (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 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 meters, 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 usually called Low Velocity Extended Range ammunition (LV-ER), which sits in between the low and medium velocity types and is specifically intended for under-barrel or single-barrel launchers. These typically have maximum ballistic ranges of 600+ meters.

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.

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.

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 that uses a conventional cartridge but differs in being of only 30mm caliber. However, the projectile is unusually long and similar in weight to the NATO 40mm HV. The maximum ballistic range was originally a few hundred meters less than the NATO HV, but recent ammunition developments have seen this increase to more than 2,000 meters. 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 30x29B (Belted) round, the RAG-30, which offers an interesting level of portable firepower as it weighs only 26½ lbs.

Apparently a version of the QLZ87 chambered for NATO 40mm HV ammunition, shown in a poster display at Eurosatory.

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 forward 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). Effective ranges are 300-400 meters. 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 meters. 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.

China initially adopted Russian equipment but has now developed its own in 35mm caliber. 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 35x32SR high-velocity DF87 series ammunition that has a ballistic range of 1,750 meters. 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 meters. It is used in a pair of automatic launchers, the belt-fed, tripod mounted QLZ04 that weighs 55 lbs including tripod (about half that of the MK19) and the even lighter, magazine-fed QLZ87 that is available bipod or tripod mounted and weighs only 44 lbs with a tripod or 26½ lbs on a bipod.

The most interesting weapon using the 35x32SR round is the lightweight semiautomatic 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 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.

In 2014 NORINCO advertised two new weapons for the export market, which appear to be versions of the QLZ87 and QLB06 modified to fire 40mm HV NATO ammunition, although no further details were available at the time of writing. Chinese companies often make products in western calibers 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 11 lbs, but has a gas-operated selective-fire mechanism capable of emptying the standard five-round magazine in one second.

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 semiautomatic gun fires standard 20mm cannon shells at subsonic velocity from a small cartridge case and, given its compact dimensions and weight of 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 meters for area fire, 600m against point targets; at a range of 300m the mid-range trajectory height is 4 feet compared with 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 caliber: the 25x40B 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 25x59B round that 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 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 meters 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 330 feet compared with 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 caliber 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 U.S. XM29, although the launcher uses a manually-operated bolt action. It weighs 13½ lbs and has a maximum effective range of 500 meters. The Chinese ZH-05 similarly combines a 20mm grenade launcher with a rifle in their standard 5.8mm caliber and looks very similar to the Korean gun, but rather surprisingly the launcher is a single-shot type with no magazine; this does help to keep the empty weight down to a reported 9.4 lbs (11 lbs loaded with a full 5.8mm magazine and a grenade). Effective range is claimed to be 800 meters, 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.

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 much 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 9 lbs and is intended to fire both LV and MV ammunition including precision
airburst rounds.

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. While the Australian parent company went into administration in July 2012, the U.S. branch continues to operate with the Canadian Army taking an interest in their products.

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. 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, China has an advantage in starting with the portable QLB06, with the new version firing 40mm HV ammunition being potentially able to use existing western
airburst systems.

(Anthony G. Williams is an independent ammunition consultant and Editor of IHS Jane’s Weapons: Ammunition. His website is at www.quarry.nildram.co.uk/consultancy)

Two of the constants that have featured in the field of U.S. military small arms for the last half-century are the AR-15 firearms family, in the form of the M16 rifle and M4 carbine, and the 5.56×45 cartridge.  Ever since the M16 and 5.56mm combination first entered service during the Vietnam War it has been a source of controversy.  It had a poor start mainly due to a change in the ammunition propellant in the process of moving from prototype to production status.  This seriously affected reliability in combat, leading to some bad headlines about guns jamming in the heat of battle.  These initial problems were soon addressed but the gun and ammunition have had their critics ever since, focused partly on the direct gas impingement operating system of the gun but mainly on the small size and power of the cartridge.  Criticism of the cartridge applies just as much to the Army’s light machine gun, the M249, which uses the same ammunition.

Both rifle and cartridge have seen many modifications and, given the conclusion in 2013 of the Army’s Individual Carbine competition without a winner, it looks as if versions of the M4 will remain in service for a long time to come.  The Army has so far shown no interest in changing the cartridge other than in modifying the bullet and loading; the original M193 gave way to the NATO-standard M855 over 30 years ago, but continued complaints about lack of effective range and erratic terminal effectiveness, combined with the Army’s wish to standardize on lead-free ammunition, led to the 2010 introduction of the M855A1 EPR (Enhanced Performance Round).  Other forces make use of different loadings including the heavy-bullet MK262 for SOCOM and the MK318 for the USMC.

Danny Mathers on the test bench.

In addition to these official developments, designers and manufacturers keep coming up with proposals for further improvements to the gun, including modifying it to use larger cartridges.  The 6.5×40 is the latest attempt to introduce a new round for the M4 platform and offers some specific benefits mainly focused on achieving extended range for military operations.

One of the strengths of the AR-15 is its versatility, making it easy to adapt the design to accommodate larger cartridges.  The main constraint is the overall length of the complete round, which must remain within the 2.26 inches (57.4 mm) of the 5.56×45 in order to avoid fundamental and costly changes to receiver/design and construction.  There are also limitations on the width of the cartridge case linked to both the width of the magazine well and the maximum chamber pressure developed by the cartridge: within the standard AR-15 external barrel dimensions, a wider cartridge means thinner chamber walls and (other things being equal) the bolt thrust will also be higher, putting more stress on the action.  Within these limitations, a very wide range of larger-caliber cartridges has been developed for the AR-15 platform, up to a maximum bullet diameter of 12.7mm in the .50 Beowulf.

The simplest type of modification is to retain the basic 5.56×45 case (adjusted in length as required), but increase the caliber to anything up to a maximum of 8.6mm as used in the straight-cased version of the .338 Whisper.  This approach has the advantages of requiring the minimum change to the gun and retaining the full capacity of the magazine.  The disadvantage is that there is no room for more propellant, in fact there may be less if the case has to be shortened to accommodate a longer bullet, so performance improvements are limited.  As a result, such cartridges are usually intended for special purposes, particularly subsonic loadings for use in suppressed weapons.  The 7.62mm caliber is by far the most popular for this purpose; the original .300 Whisper having been joined by variations on the theme, most notably the .300 AAC Blackout (300 BLK), which is virtually identical to the Whisper but SAAMI registered.  Both subsonic and supersonic loadings of these cartridges are available, but the effective range even of the supersonic loads is limited by the combination of the short, light bullets and a modest muzzle velocity.

To achieve a significant performance improvement, it is necessary to increase the diameter of the cartridge case from the 0.38 in (9.6mm) of the 5.56×45.  This is most easily achieved by adapting existing cases, so there are several steps based on available production cases.  The first step up in common use is the case for the 6.8mm Remington Special Purpose Cartridge (SPC), which measures 0.42 in (10.7mm) in diameter and was itself developed from the old .30 Remington.  Next up is the 0.44 in (11.2mm) case of the Russian 7.62×39 AK round that has since been used for a number of different cartridges, most significantly the 6.5mm Grendel.  The largest of the common case diameters is the 0.47 in (12.0mm) as used by the 7.62×51 NATO, which can trace its direct ancestry back over a century to the U.S. military .30 cartridge and has since spawned countless variations.

Left to right: 7.62mm 175gr OTM, 7.62mm 147gr FMJBT, 5.56mm 62gr FMJBT, 6.5mm Berger VLD 140gr OTM, 6.5mm Lapua 144gr FMJBT, 6.5mm Norma 120gr FMJBT, 6.8mm 115gr FMJBT.

The Origins of the 6.5×40
Mitch Shoffner of Rockingham, North Carolina, is a combat veteran who was assigned to the 82nd Airborne Division 1/508 PIR in December of 1967, served with Recon in 1968 in Vietnam with the same unit, and subsequently became a weapons specialist with A Company, 6th Special Forces Group, before leaving the army and training as a teacher.  From his own experience he was aware of the limitations of the 5.56mm cartridge, and his opinion was reinforced by complaints about its combat performance in the 1990s.  After 9/11 he decided to begin work on a new cartridge that could replace the 5.56mm, a project that was given even greater relevance by more recent events in the Middle East.

The lengthy conflicts in Iraq and Afghanistan have both featured extensive use of small arms, with contrasting results.  The M4 carbine proved well suited to the mainly urban, short-range fighting in Iraq, but circumstances changed dramatically when the Taliban began to make their come-back in Afghanistan.  Noting the limited effective range of 5.56mm weapons, they have often chosen to attack dismounted ISAF patrols in open country from distances of 500-900 meters, using SVD rifles and PKM LMGs firing the old but powerful 7.62x54R Russian round.

The response of the U.S. Army to this has been to update and reissue to the infantry squad the old M14 rifles in 7.62×51 caliber, along with the M240 7.62mm machine guns that had previously been held back as support weapons.  The main problems these brought with them were those that had caused them to be replaced by 5.56mm weapons and ammunition in the first place: gun and ammunition weight.  These problems were exacerbated by the heavy loads that modern infantry carry, especially troublesome when operating in the rugged terrain and at the high altitudes common in parts of Afghanistan.

Mitch Shoffner’s project is focused on greatly improving the long-range performance and effectiveness of the existing 5.56mm weapons by developing a new cartridge that could fit into them, with the M4 requiring only a new barrel, bolt and magazine.  He has not been the first to try to improve the performance of the AR-15 family in this way.  The two most significant attempts from the point of view of their military potential have been the 6.8×43 Remington SPC and the 6.5mm Grendel already mentioned.

The Barnes 126.5 grain lead-free hunting bullet that performs so well in the 6.5x40. Mitch comments that a variation with a steel or tungsten rather than polymer tip could meet military requirements.

The 6.8mm SPC was the result of a joint effort between Remington and members of the U.S. Special Operations Command, working in conjunction with the U.S. Army Marksmanship Unit at Fort Benning, Georgia.  The project took place before the problem of the long-range engagements in Afghanistan emerged, so the priority was to develop a round that would deliver more reliable terminal effectiveness than 5.56mm at normal combat ranges.  This it does very well by all accounts but, as Mitch discovered after experimenting with the round, the relatively short, stubby bullets blunt the long-range performance.  Using the finely-pointed long-nosed bullets needed to achieve the high ballistic coefficients required would make the 6.8mm cartridge too long to fit into the AR-15 action.

In contrast, Alexander Arms designed the 6.5mm Grendel around the use of long, low-drag bullets.  To provide enough space for their long noses without exceeding the overall length limit, the case length has been held back to 1.52 inches (38.7 mm).  To compensate for its shortness the case has been made wider than the 6.8mm’s in order to hold enough propellant.  This round can provide excellent long-range performance when bullets of around 120 grains are used, although commonly quoted muzzle velocities are usually from long (24 inch) barrels.  Furthermore, the short, wide case, with little taper and a sharp shoulder, has prompted some debate about its suitability for military use in belt-fed machine guns as well as about the potential for increased stress on the M4’s action, as described earlier.

Design and Performance of the 6.5×40
The approach that Mitch Shoffner has taken with his 6.5×40 is to design a compact, long-range military cartridge that would not experience any functioning problems in magazine or belt-fed automatic weapons.  He accordingly adopted the same 0.42 inch case diameter as the 6.8mm SPC together with a case taper and a shoulder angle similar to those of the 7.62×51.  He chose the 6.5mm caliber and a case length of 1.57 inches to allow the use of long, low drag bullets within the M4 platform.

It is worth mentioning that a 6.5mm version of the Remington case was explored during the development of the SPC but 6.8mm was preferred as it was found to have superior terminal effectiveness.  However, long range was not a priority in the development of that cartridge, and the 43 mm case length meant that the 6.5mm version could only use relatively short, light bullets.  As always in cartridge design, compromises are necessary; if you emphasize one characteristic there will be penalties elsewhere.

Comparison data is shown here, all from the 14.5 inch barrel length of the M4 carbine except for the 7.62x39 of the AKM, which is from a 16 inch barrel. The JBM Trajectory ballistic calculator has been used for all of these comparisons. The 6.5mm muzzle velocities have been measured by MagnetoSpeed chronograph. The chamber pressures of the 6.5x40 are stated to be comparable with those of the Grendel and SPC.

The use of low-drag bullets means that the initial velocity penalty compared with the equivalent 7.62×51 loads gradually reduces as the range increases.  The lightest and least aerodynamic military-pattern bullet recommended for the 6.5×40 is the 120 grain Norma FMJBT.  This loading develops 97% of the velocity of the 7.62mm M80 at the muzzle and 100% at 1,000 meters when both are fired from 14.5 inch carbine barrels.  The 144 grain Lapua FMJBT performs even better at long range, with the velocity of only 90% at the muzzle rising to 106% at 1,000 m, at which distance it also retains more energy than the M80.  The optimum bullet for long-range performance in the 6.5×40 is the 140 grain Berger VLD, a match-grade target bullet, which remains supersonic to 1,000 meters even from the 14.5 inch carbine barrel – an impressive statistic given the modest initial velocity.

Mitch has sought the views of other combat veterans concerning the characteristics of his cartridge.  MSG Danny Mathers is a ten-year veteran with the Combat Materials Evaluation Element (CMEE) and a master sniper with experience of all types of weapons and combat, and was part of the early development of the M4 with the CAR15 platform. He comments: “I was immediately impressed with the power and the accuracy at 400 meters with his carbine chambered in a 6.5mm cartridge.  I later fired several of his weapons at a police range on full auto [and] I could not believe the natural control of the weapon with a standard flash suppressor.  I have no doubt that the 6.5×40 is the most logical improvement to the assault rifle.  The conversion is simply the most cost effective improvement available.”

SFC Charles Williams was a U.S. Army Special Forces sniper with the 5th in Iraq, and as a very experienced hunter has been testing the 6.5×40 in the field to evaluate its effectiveness.  He has used rifles with barrels ranging from 14.5 to 24 inches and has found the 6.5mm to be accurate and highly effective, bringing down over 20 deer and coyote.  He has tested a wide variety of bullets and found the Barnes 126.5gr LRX to be most effective.  He comments: “The round has performed extremely well in every situation.  I documented every harvested animal with wind, weather, distance, round impact site, internal organ damage, and exit site.  No animal required more than one shot to bring down.  The damage performed by the round was the same at 375 yards as it was at 3 yards.”

Mitch Shoffner and his daughter Stephanie with two of his 6.5x40 rifles. Both rifles use an ADC (Arnold Dew Custom) adjustable carbine length piston gas system, which Mitch says is a low maintenance system. Both also use Noveske HBAR Taper barrels with a SureFire adapter/flash hider. The rifle held by Mitch has a 14.5-inch barrel with a 1:7 twist. Stephi’s has a 12.5-inch barrel with a 1:8.5 twist. The stocks on both are Magpul CTR. Mitch’s rifle is fitted with a TA11 3.5x35 ACOG sight while Stephi’s has an Aimpoint M2 red dot sight. The lower and upper receivers are all Mil-Spec and Mitch has used various brands – Colt, Tri Star, DPMS, Rock River, Sun Devil, etc. Any 6.8mm Rem SPC magazines can be used; Mitch finds that PRI are the best.

What all of this means is that the 6.5×40 remains an effective cartridge out to ranges at least equal to those of the equivalent 7.62×51 loadings, while fitting into appropriately modified versions of 5.56mm weapons and saving around 30% of the 7.62mm’s ammunition weight.  It is not intended to replace the 7.62mm cartridge, but as a replacement for the 5.56mm it could make it unnecessary for dismounted soldiers to carry the 7.62mm weapons that would be retained for the support role.

The 6.5×40 clearly has some very desirable characteristics, but given that all cartridges are compromises, what are the downsides in this equation?

The most obvious one is that the ammunition is some 30% heavier than 5.56mm.  It also has a greater recoil impulse although, as comparative testing has revealed with other cartridges of this power such as the 6.8mm Remington, the perceived recoil is much closer to the 5.56mm than it is to the 7.62mm and controllability is not seriously affected.  Another inevitable downside is that the lower initial velocity means a steeper trajectory at medium ranges compared with the 5.56mm.  At 300 meters, the 5.56mm M855A1 drops around 16 inches when zeroed at 100 meters, while the 6.5mm 120 grain Norma drops 20.5 inches.  These comparisons are however only relevant for distances that are within the relatively short effective range of 5.56mm weapons.  If troops ever need to engage at longer ranges, the only valid comparators are the 7.62mm systems, which have trajectories not very different from the 6.5×40.

A potential issue is that of terminal effectiveness against unprotected personnel, which is affected by the bullet’s yaw characteristics.  If the bullet does not yaw shortly after impact, it may just punch a neat hole through the body.  This may not matter so much at longer ranges when the primary problem is hitting the target at all, but the shorter the range, the more vital it becomes to incapacitate the enemy as quickly as possible before he can kill you.

With all small arms ammunition, bullet placement is the most important factor: immediate incapacitation will only occur if the central nervous system is hit.  However, this is a small target, and with hits elsewhere on the body, the larger the wound channel created, the faster incapacitation is likely to be.  Choosing or designing bullets that demonstrate rapid and reliable yaw characteristics to maximize the size of the wound channel are therefore important.

The 6.5x40 loaded with a Lapua 144 grain FMJBT compared with other rounds.

If a yaw performance similar to that of the 5.56mm can be achieved then the long 6.5mm bullets, twice the weight of the 5.56mm, should deliver more reliable terminal effectiveness.  They should also penetrate intermediate barriers more easily, given their high sectional density.  By comparison, the 7.62mm M80’s yaw performance is not particularly good and the sectional density is worse than the 6.5mm, but its sheer size and power provide some compensation for that.

Another potential downside is that the 6.5×40 cartridge really requires the use of heavy, lead-cored bullets to deliver the full performance potential at long range.  Replacement of lead with less dense materials such as copper or steel entails a reduction in bullet weight and therefore ballistic coefficient and long-range performance.  The alternative approach of lengthening the bullet to maintain the weight isn’t really feasible since that would leave too little room for propellant in the case thereby reducing the velocity at all ranges, and the heavier bullets could also become too long to stabilize properly.  These problems could be resolved by using tungsten cores, which would also deliver effective armour penetration but at considerable material cost.  Tungsten is also a controversial material to have accumulating in the environment of practice ranges.

Having said that, it is worth noting the performance of the Barnes 126.5 grain LRX in the table above, which is a solid copper bullet with a polymer tip.  An efficient nose shape helps this to match the long-range performance of the lead-cored 120 grain Norma FMJBT.

Finally, there is the issue of suitability for use with polymer/metal hybrid cases, which are steadily being developed towards military acceptance.  These reduce ammunition weight by 23-32% depending on design and materials, so are likely to be adopted very quickly as soon as they prove satisfactory.  However, they have thicker walls and will therefore reduce the propellant capacity to some degree.  In compensation, there is some evidence that they may be thermodynamically more efficient since polymer is such a good insulator that very little of the energy generated is lost in heating up the case or the chamber, but that remains to be tested for each cartridge.

To sum up, the 6.5×40 offers an intriguing mix of characteristics that could well make it attractive for those armed forces who need a much better long-range performance than 5.56mm can offer, don’t want to burden dismounted infantry with carrying the extra weight of 7.62mm guns and ammunition, do want to retain their light and handy 5.56mm weapons and, for optimum performance, aren’t too concerned about lead-free bullets.  If these characteristics appeal, then the 6.5×40 is worth careful study.

ABOVE: Nammo Lapua .308 subsonic.

The origin of the company lies in the establishment by the Finnish government in 1923 of a cartridge factory in the town of Lapua in western Finland.  The State Cartridge Factory (as it was named in 1927) was the main supplier of ammunition to the Finnish Army during the Winter and Continuation Wars with the USSR between 1939 and 1944.  In 1991 it became an independent company under the new name Cartridge Factory Lapua, Ltd.  The next year, Lapua acquired the German cartridge factory SK Jagd- und Sportmunitions GmbH.  In 1996, Finnish military manufacturers were combined under the banner of Patria Industries; Lapua became Patria Lapua.  In 1998 Patria Industries Oyj from Finland, Celsius AB from Sweden and Raufoss ASA from Norway together formed the Nammo Group (Nordic Ammunition).  In Finland, Nammo Lapua Oy became part of the Nammo Group.  Since 2005, Nammo AS has been 50% owned by Patria Oyj and 50% by the Norwegian government.

The core business of the Nammo Group is the development, testing, production and sale of military and sport ammunition, shoulder launched weapons systems, rocket motors for military and space applications and leading global services for environmentally friendly demilitarization.  Nammo is present in eight countries with a total of eighteen production sites and sales offices.  The group operates through its five business units: Small Caliber, Medium & Large Caliber, Missile Products, Demil, and Nammo Talley.  The Small Caliber Group is based in Finland and manufactures military ammunition under the Nammo brand with the Lapua name used for commercial target, hunting and special purpose ammunition.  All of Lapua’s special purpose ammunition is produced to the same match grade requirements as their target ammunition.

Tactical Ammunition
The Nammo Small Caliber military ammunition product range comes in the following calibers: 9×19; 5.56×45; 7.62×51 and .338 Lapua Magnum.  The bullet types available are as follows:

• Ball: 5.56mm, 7.62mm, .338 Lapua Magnum
• Non-toxic: 5.56mm, 7.62mm, 9mm
• Armour piercing: 5.56mm, 7.62mm, .338 Lapua Magnum, 9mm
• Tracer: 5.56mm, 7.62mm
• Infra-red: 5.56mm, 7.62mm
• Subsonic: 9mm
• Reduced Range: 5.56mm, 7.62mm

In addition, the Lapua range of Special Purpose ammunition includes .223 Remington (5.56×45), 7.62×39, .308 Winchester (7.62×51), and .338 Lapua Magnum.  The bullet types available are:

• Ball (FMJ): .223 Rem, 7.62×39, .308 Win
• Lock Base (FMJBT): .308 Win, .338 Lapua Magnum
• Scenar: .223 Rem, .308 Win, .338 Lapua Magnum
• Scenar-L (improved Scenar): .223 Rem, .308 Win
• Subsonic: .308 Win
• Armour piercing: .308 Win, .338 Lapua Magnum
• Armour piercing incendiary: .338 Lapua Magnum

Examples

1) Nammo Non-toxic: 5.56mm.  Most ammunition contains lead and other toxic material, which is increasingly a problem given growing public awareness of environmental issues and ever more stringent requirements to protect the environment.  This affects the armed forces, with many of the existing small arms training ranges likely to close due to potential groundwater contamination.  The problems are even worse in the closed quarters of an indoor range.

Nammo has responded by developing non-toxic ammunition free from heavy metals in the projectile, powder and primer.  While initially used for training this has been designed to achieve full military performance, at least as good as existing lead-cored ammunition.  This is NATO qualified in 5.56x45mm ball and 7.62x51mm ball and tracer loadings and has been in service with armed forces and federal agencies for several years.

The 5.56mm ball resembles the SS109/M855 bullet in being an FMJ design with the gilding metal jacket fully enclosing the core except at the base, and with the front part of the core consisting of a hardened steel penetrator.  The difference is that the rest of the core is of steel rather than lead.  The first version of this ammunition, designated NT 4 HP, was NATO qualified in 2004 by which time it was already in service with Sweden and Norway.  In 2009, complaints concerning health issues began to arise from Norway concerning the use of this ammunition with their new HK 416 rifles in indoor ranges.  After a detailed investigation the source was identified as copper and zinc emissions resulting from the interaction between the bullet and the relatively tight HK 416 barrel (interestingly, while the NT 4 HP produced more such emissions than the M855, it produced fewer than the M855A1).  A redesign effort resulted in the BNT 4 HP Mk2, which significantly reduced the emissions while delivering improved accuracy (equal to or less than 2 MOA) and enhanced penetration (3.5mm steel plate at 700 m, compared with 550 m minimum requirement for SS109).  Lethality is also improved, with the bullet beginning a rapid yaw after penetrating less than 2.5 inches (60mm) into a soft target.

Specifications

Bullet: 62 grain (4 g) FMJ with steel core, the front element of which is hardened
Case: brass
Muzzle velocity: 3,050 fps (930 m/s)
Muzzle energy: 1,280 ft lbs (1,730 J)
Accuracy: not more than 2 MOA
Temperature range: -65ºF to +126ºF (-54ºC to +52ºC)

2) Lapua Subsonic: .308 Win/7.62×51.  The subsonic loading is intended for use in suppressed rifles at ranges of up to 300 yards.  The bullet is a conventional, streamlined heavy ball.  The muzzle velocity of 1,066 fps only falls to 941 fps at 300 yards, the bullet retaining 78% of its starting energy.  When zeroed in at 100 yards and assuming a scope 1.6 inches above the bore line, the bullet drop is 32 inches at 200 yards and 100 inches at 300.  If zeroed in at 300 yards the trajectory is 33 inches above the sight line at 100 yards and 35 inches at 200 yards.  A sidewind of 13 fps (9 mph) will deflect the bullet by 1 inch at 100 yards, 4 inches at 200 and 9 inches at 300 yards.

Specifications
Bullet: FMJ Boat-tailed, 200 grains (13 g), G7 ballistic coefficient = 0.211
Case: brass
Muzzle velocity: 1,066 fps (325 m/s) from 16 inch (406mm) barrel
Muzzle energy: 506 ft lbs (682 J)

3) Lapua Armour Piercing Incendiary: .338 Lapua Magnum.  The origin of this cartridge lies in a 1980s project by the U.S. company Research Armament Industries to meet a USMC requirement for a long-range sniper rifle, based on necking-down the case of the old .416 Rigby big-game cartridge.  This was unsuccessful but a few years later Lapua picked up the idea, reshaped and strengthened the case to withstand higher operating pressures, and launched it as the .338 Lapua Magnum.  With an effective range of up to 1,500 metres, this has become highly successful and has been adopted by many armies for long-range sniper rifles.  For example, British Army snipers switched over to this calibre a few years ago, replacing the 7.62×51 NATO.

Lapua offers a wide selection of .338 LM ammunition including Ball, Armour Piercing, Armour Piercing Incendiary, HPBT, Blank and Drill cartridges.  The trajectory of most of the bullets is tailored to match, so there is no need to change the sight setup when changing a bullet type.

The Armour Piercing Incendiary loading is part of the trend to use pyrophoric (spark producing) metals in the bullet tip rather than chemicals, both to signal the point of impact against a hard surface and to have some incendiary effect after penetrating.  In bullets from other makers titanium is typically used for this, but Lapua has chosen to use zirconium tip in front of the hard metal penetrator.  The 253 grain bullet is launched at 2,935 fps and is still travelling at 1,518 fps at 1,000 yards.  When zeroed at 300 yards, the bullet strikes 4 inches high at 100 yards and 5 inches high at 200 yards.  If zeroed at 600 yards it shoots 25 inches high at 300 yards and 58 inches low at 800 yards.  A 13 fps (9 mph) crosswind will deflect the bullet by 4 inches at 300 yards and 19 inches at 600 yards.

Specifications:

Bullet: 253 grains (16.4 g) boat-tailed bullet with brass jacket and base, a tungsten carbide core and an exposed pyrophoric metal tip. G7 ballistic coefficient = 0.290.
Case: brass
Muzzle velocity: 2,935 fps (895 m/s) from a 27 inch barrel.
Muzzle energy: 4,938 ft lbs (6696 J)

Nammo Lapua – Small Caliber Division
Äyritie 8 D, 5th floor
FI-01510 Vantaa
Finland
www.nammo.com/Business-Units/Small-Caliber-Ammunition/

Contact
Phone +358 10 5233 800
Fax +358 6 4310 425
Email: scd@nammo.com

The origin of RUAG Ammotec can be traced back to the Eidgenossische Munitionsfabrik established by the Swiss Confederation in Thun in 1863.  In 1995, this was merged with another Swiss firm, Munitionsfabrik Altdorf to form the Schweizerische Munitionsfabrik (SM), following which expansions and reorganization occurred rapidly.  In 1999, RUAG Holding was formed to incorporate SM; the name changed to RUAG Munition in 2001.  The small arms ammunition sector of Dynamit Nobel was acquired in 2002, leading to the change of name to RUAG Ammotec.  Dynamit Nobel had previously acquired RWS, Geco, and Norma.  In 2003, RUAG took over the sales and trademark rights of the Austrian company Hirtenberger AG, and in 2008 absorbed MFS 2000, the Hungarian ammunition company.  RUAG Ammotec, Tampa, Florida USA was formed in 2009.

RUAG Ammotec is part of RUAG, an international aerospace and defence technology group with a workforce of 7,700 employees worldwide.  RUAG Ammotec’s headquarters are in Thun, Switzerland, but it has locations in Germany, Austria, France, UK, Belgium, Sweden, Hungary, and the USA, with manufacturing plants in five countries.  The company focuses on the production of ammunition in three categories: Law Enforcement and Armed Forces; Hunting & Sports; and Industrial Products.  Well-known names in the Hunting & Sports section are RWS, Rottweil, GECO, Norma and Hirtenberger.

Tactical Ammunition

RUAG Ammotec produces pistol and rifle ammunition designed for specialist military and law enforcement purposes as well as conventional military rounds.  Calibers available are: 4.6×30 (HK MP7); 9×19; 5.56×45 and .223 Remington; 7.62×51 and .308 Winchester; .300 Whisper; .300 Winchester Magnum; .338 Lapua Magnum; and 12.7×99 (.50 BMG).  Training rounds, plus the 12 gauge Magnum ENTRY door breaching rounds, are also offered.  The SWISS P line consists of precision ammunition intended for snipers and designated marksmen.

The types of ammunition manufactured include the following:

• FMJ (lead-cored jacketed bullet, SINOXID non-corrosive primer): 9×19; 5.56×45; 7.62×51 (M80)
• FMJ HA (High Accuracy, a selected version of the Swiss Army’s GP90: fully-encapsulated lead-cored, steel- jacketed bullet): 5.56×45
• HC (Hard Core bullet): 5.56×45 (FMJ-SS109); 7.62×51 and .50 BMG (steel-cored bullet with brass semi-jacket and exposed tip)
• LF HC SX (brass jacket and core with hardened steel tip within jacket): 5.56×45;
• FMJ SX (non-toxic, with SINTOX lead-free primer): 4.6×30; 9×19 (fully encapsulated lead-cored bullet);
• FMJ SXF (FMJ SX with the addition to the primer of the marking agent Gadolinium to assist forensics): 9×19+P;
• FMJ SECA SXF (lead free, brass deformation bullet): 9×19+P;
• ACTION series (lead free, brass hollow-point bullet): 4.6×30; 9×19 (plastic-tipped),
• HP SXF: 9×19;
• AP SX: 4.6×30 (copper-plated steel bullet); 9×19 (tin-plated brass bullet)
• AP TC (lead and tungsten carbide-core bullet): 5.56×45
• Tracer: 9×19; 5.56×45 (M856 – IR version also available); 7.62×51 (M62)
• Subsonic FMJ: 9×19;
• Subsonic HP SX: 9×19;
• Frangible SX (bullet is sintered copper): 9×19; 5.56×45;
• Frangible COPPER-MATRIX SX (bullet is copper in polymer matrix): 9×19; 5.56×45;
• SWISS P Ball (jacketed lead core): .223 Rem; .308 Win; .300 Win Mag; .338 Lapua Mag
• SWISS P Target (brass-jacketed with open point and lead core): .223 Rem; .308 Win; .300 Whisper (subsonic); .300 Win Mag; .338 Lapua Mag
• SWISS P Styx Action (brass-jacketed, lead-cored, hollow point): .223 Rem; .308 Win; .300 Win Mag; .338 Lapua Mag
• SWISS P Armour Piercing (brass-jacketed, lead and tungsten carbide core): .223 Rem; .308 Win; .300 Win Mag; .338 Lapua Mag
• SWISS P Final SR (short range, lead-cored brass-jacketed hollow-point): .223 Rem; .308 Win
• SWISS P TACTICAL (brass, blunt-nose bullet for penetrating glass): .308 Win; .300 Win Mag; .338 Lapua Mag
• SWISS P Subsonic (HPBT Match bullet): .308 Win; .338 Lapua
• SWISS P Subsonic Final (JHP with fragmenting core of pressed lead pellets): .308 Win; .300 Whisper
• SWISS P API (brass-jacketed bullet with tungsten core and titanium tip): .338 Lapua Mag

Examples

1) 5.56×45 LF HC+SX. The 5.56mm LF HC+ SX is specifically designed to NATO standards in order to achieve improved penetration over a longer range.  The bullet mainly consists of a hardened steel core, which comprises two-thirds of the bullet weight.  The brass shoe is in effect a semi-jacket wrapped around the rear half of the core in order to take the rifling.  This design provides minimal barrel wear and allows outstanding accuracy as well as excellent penetration on hard targets.  A high performance powder ensures an extra long shelf life under extreme conditions; the round is fully compliant with climate zone A1 requirements.  The LF HC+ SX round is particularly suited to use in machine guns and is also available linked in belts, in mixed ratios with other loadings according to the customer’s requirements.

Specifications:

• Bullet: hardened steel core with a brass shoe; weight 4.0 g / 62 grains
• Case: brass, w/ SINTOX non-toxic primer
• Cartridge weight: 12.2 g / 188 grains
• Muzzle velocity: 935 m/s (3,068 fps) from 510 mm (20 inch) barrel
• Muzzle energy: 1,730 J (1,284 ft lbs)
• Accuracy at 300 m: 100% radius ≤ 50 mm (2 inches)
• Packaging: in cardboard boxes of 20 or 600 rounds.

2) .308 Winchester SWISS P Tactical.  The SWISS P Tactical rounds are specifically designed to hit targets behind an angled window or car windshield without the risk of unpredictable bullet deflection that might endanger bystanders.  Conventional bullets break apart or fragment when penetrating glass, which makes accurate shooting impossible.  At least 90% of the residual body of the RUAG SWISS P Tactical bullet stays intact, it maintains its trajectory after penetrating glass, and it does not fragment at all.  The bullet is solid brass with a flat tip.

RUAG SWISS P rounds are made to achieve match grade accuracy with coordinated ballistics and shooting characteristics from lot to lot.  All .308 Win. SWISS P Ball, Target, Styx Action and Armour Piercing have an identical point of impact at 100 m, which allows the shooter to instantly change the bullet type.

Specifications:

• Bullet: solid copper, flat-nosed and boat tailed; weight 10.6 g / 163 grains.
• Case: brass, with SINOXID non-corrosive primer
• Cartridge weight: 24.6 g / 380 grains
• Muzzle velocity: 820 m/s (2,690 fps) from 650 mm (25.6 inch) barrel
• Muzzle energy: 3,965 J (2,940 ft lbs)
• Accuracy at 300 m: 100% radius ≤ 50 mm (2 inches)
• Packaging: in cardboard boxes of 20 or 200 rounds.

3) .300 Whisper SWISS P Subsonic Final.  The calibre .300 Whisper was especially designed for subsonic shooting.  The proportion of the chamber size and the amount of powder are optimized to ensure constant pressure build up and first hit probability.

The special bullet made from pressed pellets instantaneously disintegrates when hitting a soft target even at subsonic speed.  The penetration depth of the fragments is extremely small, minimizing the risk of over penetration and increasing the safety of bystanders.

Optimized for use in suppressed weapons, the muzzle bang is minimized and the supersonic crack is eliminated.  Excellent first hit probability

• For silent and highly accurate secondary target shooting
• Perfectly suitable for missions in urban terrain without attracting attention or loosing the element of surprise
• All components are specially designed and adjusted to each other
• Long weapon durability due to minimal barrel wear and smoke residue build up

Specifications:

• Bullet: tin plated tombac jacket contained pressed lead pellets, weight 13.0 g / 200 grains
• Case: brass, with SINOXID non-corrosive primer
• Cartridge weight: 21.0 g / 324 grains
• Muzzle velocity: 310 m/s (1,017 fps) from 450 mm (17.7 inch) barrel
• Muzzle energy:  625 J (464 ft lbs)
• Accuracy at 50 m: 100% radius ≤ 100 mm (4 inches)
• Packaging: in cardboard boxes of 20 or 600 rounds.

RUAG Ammotec AG
Uttigenstrasse 67
3602 Thun
Switzerland
www.ruag.com/en/Ammotec
Contact: Sabine Brechbühl
Phone +41 33 228 22 20
Fax +41 33 228 26 27
Email: via website

However, earlier this year the competition was criticized by the Defense Department, resulting in the Army announcing in May the suspension of the tests amid rumors of imminent cancellation. To forestall this, the House of Representatives Armed Services Committee voted in June in favor of an amendment to the 2014 National Defense Authorization Act which would require the Army to complete the competition. Only a few days later the situation changed again, with the Army announcing that “the Individual Carbine (IC) competition will formally conclude without the selection of a winner. None of the carbines evaluated during the testing phase of the competition met the minimum scoring requirement needed to continue to the next phase of the evaluation.” It appears that the high-pressure M855A1 EPR ammunition used in the tests caused problems with achieving the reliability target.

In parallel with the competition, the Army has been running an improvement program for an M4A1 Carbine, involving the replacement of the 3-round burst with automatic fire and the provision of a heavier barrel (with further improvements planned), and orders for the this improved version have already begun to be placed. The winner of the carbine competition was supposed to be tested against the improved M4A1 to determine which should be purchased in the future. The Army now plans to continue acquiring the M4A1.

U.S. M4 Carbine fired from ship with ACOG optic. (Chris Bartocci)

At the same time, there has been an apparent cooling of interest in the Army’s Lightweight Small Arms Technologies (LSAT) program, involving the development of advanced caseless and plastic-cased telescoped 5.56mm ammunition and associated machine guns and carbines.  The weight savings achieved with the prototypes have been in the order of 40%, but the recent statements by the Army indicate that there are no plans to procure a production weapon, at least for the time being.  Presumably the new production facilities required for both guns and ammunition are a factor, coupled with the fact that substantial weight savings are also being achieved by prototype polymer/metal hybrid versions of conventional cartridge cases fired from conventional guns – a technology involving far less cost and risk.

So if both the new carbine and LSAT are out of the picture (at least for the time being), what next?  Will the U.S. Army continue to rely on the 5.56mm M4A1 for the foreseeable future?  Or will the opportunity be taken to rethink the characteristics of the standard infantry rifle, which will necessarily involve changing the performance requirements of the ammunition?  A Congressional study currently underway indicates that the possibility of a change in caliber may be seriously considered.

The Congressional Study
The House of Representatives Report 112-705 on the National Defense Authorization Act for Fiscal Year 2013 was published in December 2012. Section 158, titled Study on Small Arms and Small Caliber Ammunition Capabilities, included the following provisions:

“Not later than 30 days after the date of the enactment of this Act, the Secretary of Defense shall enter into a contract with a federally funded research and development center to conduct a study on the requirements analysis and determination processes and capabilities of the Department of Defense with respect to small arms and small-caliber ammunition that carries out each of the following:

(A) A comparative evaluation of the current military small arms in use by the Armed Forces, including general purpose and special operations forces, and select military equivalent commercial candidates not necessarily in use militarily but currently available.

(B) A comparative evaluation of the standard small-caliber ammunition of the Department with other small-caliber ammunition alternatives.

(C) An assessment of the current plans of the Department to modernize the small arms and small-caliber ammunition capabilities of the Department.

(D) An assessment of the requirements analysis and determination processes of the Department for small arms and small-caliber ammunition.”

Vietnam 1965. U.S. rifle M16 E1 with forward assist and 3 prong flash hider. (Chris Bartocci)

Further paragraphs specify that this study shall take into account a number of factors, including current and future operating environments, capability gaps in small arms and small-caliber ammunition identified by the Department, and the results of any studies carried out by the Department of Defense Small Arms and Small-Caliber Ammunition defense support team.

The Secretary is required to submit to the congressional defense committees a report containing the results of this study no later than September 30, 2013.

The story behind this study is complex but of considerable significance.

The Background – NATO Ammunition
The current NATO rifle and machine gun cartridges on which this congressional study will be focusing are the 5.56mm and 7.62mm rounds.  The 7.62mm (technically, 7.62×51) was developed in the USA and adopted by NATO in the 1950s in order to obtain one standard, all-purpose small-arms cartridge used by all NATO nations and interchangeable between the weapons of NATO armed forces.

The 7.62mm NATO proved to be hard-hitting and long-ranged, but the experience of fighting in Vietnam began to reveal some disadvantages: it was unnecessarily powerful, requiring heavy guns to fire it, generated too much recoil for automatic rifle fire to be controllable, and the ammunition weight limited the quantity that could be carried, especially important for machine guns.  Meanwhile, the enemy was supplied with light and compact Kalashnikov carbines that fired the less powerful 7.62×39 Russian cartridge and were thereby capable of effective automatic fire.

The U.S. forces acquired some lightweight M16 automatic rifles in the 1960s, intended as an interim solution, using a new 5.56×45 cartridge made by Remington.  After initial teething problems this gun and ammunition combination proved well suited to the close-quarter jungle fighting and saw increasing use throughout the army, eventually virtually replacing 7.62mm M14 rifles in the U.S inventory.  The 7.62×51 ammunition was mainly retained for use in machine guns and sniper rifles.

By the 1970s there was a clear consensus among the NATO nations that a smaller and less powerful cartridge should be adopted to supplement the 7.62mm.  At the end of that decade the 5.56×45 was chosen, albeit in a new loading with a longer effective range, known as the SS109 (or M855 in U.S. service).  Various automatic rifles and light machine guns were developed to use this cartridge, which weighs only half as much as the 7.62mm round and also generates much less recoil.  The effective range was acknowledged to be shorter than the 7.62×51, but it was comparable with the Russian 7.62×39 and the newer 5.45×39 Kalashnikov rounds, and was deemed to be adequate for the battle conditions expected in a European war.  In many NATO armies, 5.56mm weapons entirely replaced 7.62mm ones at squad level, with the heavier 7.62mm machine guns being moved back to the support role.

Soldier on patrol in Vietnam in the mid 1960s with a U.S. rifle, 7.62mm M14 w/ 20-round magazine. (Chris Bartocci)

The Small-Caliber Ammunition Problem 1: Effectiveness
The first concerns about the performance of the 5.56mm M855 began to appear after the fighting in Somalia in 1993, when some U.S. troops complained that the bullets were often proving to be ineffective even at short range.  Similar anecdotes appeared following the invasion of Iraq in 2003, but were countered by other examples of the ammunition’s effectiveness.  It took some time and much laboratory research to discover what was going on.  It was found that the effectiveness of the M855 bullet varied considerably, depending on its angle of yaw when it struck the target.  Yaw in flight affects all pointed bullets to some degree, but the M855 proved to be unusually sensitive to this, resulting in dramatic variations in its effectiveness.

After this problem was identified, work commenced in the U.S. to develop 5.56mm bullets that would deliver more consistent effects.  The U.S. Army wanted at the same time to convert to “green” (i.e. lead-free) ammunition, due to concerns about lead build-up on practice ranges.  A protracted development effort during the 2000s eventually resulted in the M855A1, known initially as the LFS (lead-free slug) and subsequently as the EPR (Enhanced Performance Round), which began to enter service in 2010.  This replaces the lead core with a copper one but retains the steel tip intended to give the M855 enhanced penetration, although this is larger and is exposed instead of being concealed within the jacket.  It is claimed that the M855A1 delivers improved terminal performance and penetration.  However, to provide such performance from the short-barreled M4 carbine, the chamber pressure is higher than the M855 (apparently 62,000+ psi instead of 55,000 psi), reportedly resulting in increased barrel wear and a reduced gun life.

In the meantime, the U.S. Marine Corps became impatient with the long development of the M855A1 and acquired an entirely different new loading of the 5.56mm, the MK318 Mod 0 SOST (Special Operations Science & Technology).  This is basically a copper-alloy bullet with a lead core in the nose.  It is said to provide both more consistent anti-personnel performance and improved barrier penetration – an inherent weakness of the light 5.56mm bullets, which cannot plough through as much material as the heavy 7.62mm.

These new loadings may go some way towards resolving the erratic short-range effectiveness that afflicts the M855.  It is unlikely that they will ever achieve NATO standardization, however, since neither of them complies with the wording of the Hague convention of 1899 (subsequently subsumed into the Geneva Conventions), which bans the use of “bullets which expand or flatten easily in the human body, such as bullets with a hard envelope which does not entirely cover the core, or is pierced with incisions.”  In neither the M855A1 nor the MK318 does the bullet jacket enclose the tip.  U.S. lawyers argue that the Hague wording was intended to prohibit expanding bullets, and as neither of the new 5.56mm loadings are designed to expand they comply with the spirit of the Conventions, but British and some other NATO lawyers take a more literal view of the text.

The Small-Caliber Ammunition Problem 2: Range
An additional and even more serious problem with the 5.56mm became evident in the open-country fighting that has characterized much of the conflict in Afghanistan.  The maximum effective range of the NATO cartridge depends very much on the circumstances and particularly on any crosswinds, since the little bullet is relatively easily blown off course at longer ranges as well as shedding energy rapidly.  While acknowledging that the gun and ammunition combination is capable of precision long-range shooting in the right hands, many military sources therefore put the practical effective range in the 300-400 meter bracket.

The insurgent forces opposing the ISAF troops quickly noted this shortfall and began to make more use of their PKM light machine guns and SVD rifles rather than the AKM carbines, since these guns fire the old 7.62x54R Russian round, which is at least as powerful and long-ranged as the 7.62×51 NATO.  The result is that the normally expected 300 meter limit for most small-arms engagements was suddenly extended to 900 meters, with some reports indicating that more than half of the insurgent attacks were being launched from 500 meters or more.  5.56mm weapons were never intended to cope with such long-range engagements, and they cannot effectively do so.

Furthermore, the 5.56mm weapons are much worse at suppression (one of the primary functions of small-arms), partly because the bullets are less likely to pass close by the target due to wind drift, partly because the sonic bang they make is quieter since that is linked to bullet weight.  As a result, 5.56mm fire has little suppressive effect at longer ranges, according to a 2009 British Army study into target suppression in combat.

The result of this range crisis was that ISAF forces rushed their old 7.62×51 weapons back into the infantry squad as quickly as possible, even manually-loaded bolt-action sniper rifles being pressed into service.  Thousands of old self-loading M14 rifles were updated and re-issued to U.S. troops, and new 7.62mm rifles and LMGs have been acquired by several armies.  The existing 7.62mm FN General-Purpose Machine Gun (M240) in common use by ISAF forces made a welcome return to the front line, but with the most unwelcome consequence of increased weight.  Western infantry is already burdened by massive combat loads, and doubling the weight of ammunition belts to be carried just adds to that problem.  But as the PM Soldier Weapons Assessment Team reported in 2010: “lethality trumps weight reduction when extended ranges are required.”

To add insult to injury, the insurgents’ PKM machine gun is only about two-thirds of the weight of the M240, despite having a similar performance.  Some armies have therefore acquired the FN 7.62mm Minimi (MK48) to replace at least part of the 5.56mm inventory, but that does nothing to reduce the ammunition burden.

In summation, recent combat experience has shown that, even with improvements in effectiveness, which are unlikely to prove acceptable across NATO, the 5.56mm cartridge is inadequate at extended small-arms ranges.  This should not have caused any surprise as the little cartridge was never designed for that.  In contrast, the 7.62mm does the job, but is too heavy and generates too much recoil.  So NATO is left carrying two small-arms suites in two calibers, neither of which is satisfactory in providing the basis for a standard rifle and machine gun weapon system.

M4 Carbine. (Chris Bartocci)

What that means on the ground is that infantry patrols routinely carry weapons in both calibers, since they are unlikely to know in advance whether any small arms engagements will be at long range, short range or both.  The obvious problem that this causes is that only those with 7.62mm weapons will be able to engage the enemy effectively at long range, while only those with 5.56mm weapons will be well-equipped for close combat such as house-clearing.  So in most engagements, only a part of each squad will be fully effective.  The two-caliber solution also causes issues with ammunition sharing and resupply.

Studies Into Alternative Calibers
The question implicitly being asked by the congressional study is really this: is there a viable alternative to the existing two calibers?  Can one general-purpose cartridge have the characteristics necessary to match or beat the 7.62mm at long range, while weighing a lot less and developing much less recoil?  Several studies suggest that this is entirely feasible.  Just to focus on the most recent and relevant ones, reports from both ARDEC (the U.S. Army Armament Research, Development and Engineering Center) and AMU (the U.S. Army Marksmanship Unit) point the way forward.  Neither report has been released to the public, but some of their findings have become known.

An ARDEC review in 2009-10 examined several different calibers for future infantry rifles in terms of performance metrics that included: penetration; terminal effectiveness; accuracy; initial, retained and striking energy; wind drift; stowed kills; and recoil.  5.56mm and 7.62mm rounds were compared with 6mm, 6.35mm and 6.8mm, in all cases when loaded with lead-free copper and steel bullets to represent the EPR.  The outcome of the study was that both 6.35mm and 6.8mm comprehensively outperformed the others in their overall balance of characteristics.

In 2011-12 AMU also carried out a study into the optimum cartridge for a future infantry carbine, and concluded that the cartridge length and diameter should be greater than 5.56×45, the caliber should be 6.5mm and the muzzle energy around 2,500 J.  Low-drag bullets would be used to provide good long-range performance, enabling the smaller bullet to catch up with and eventually beat the 7.62mm in terms of retained velocity and energy, flatness of trajectory and wind drift.

It isn’t just the U.S. which is conducting such studies.  The Department of Applied Military Science in Canada recently carried out a Small Arms Intermediate Calibre Study as part of their Small Arms Modernization and Small Arms Replacement Projects.  They compared the external ballistics of the 5.56mm and 7.62mm NATO with commercially available 6.5mm and 6.8mm rounds of intermediate power, and concluded that the 6.5mm round firing low-drag bullets delivered by far the best long-range ballistics, including resistance to wind drift.

The case for such a general-purpose cartridge was strongly made in a report that emerged from the U.S. Army’s Program Executive Office Soldier in 2011: Soldier Battlefield Effectiveness. This analysis covers a lot of ground but the following quotes concerning the ideal characteristics of future infantry rifles and their ammunition are the most relevant:

“A Soldier must be able to engage the threat he’s faced with – whether it’s at eight meters or 800.”

“To be effective in all scenarios, a Soldier needs to have true “general purpose” rounds in his weapon magazine that are accurate and effective against a wide range of targets.”

“Weapons…. must be accurate and capable of engaging the enemy at overmatch distances.”

Early M16 w/ no forward assist, waffle magazine and duckbill flash suppressor (Vietnam). (Chris Bartocci)

The Options
Are there any cartridges available off-the-shelf that could provide the basis for the general-purpose round identified by ARDEC and AMU?  A survey of existing commercial ammunition indicates “not quite.”  There are some powerful 6.5mm cartridges, such as the 6.5×47 Lapua and .260 Remington, which comprehensively outperform the 7.62mm in virtually every respect, but they provide little in the way of weight or recoil reductions.  Conversely, there are some smaller cartridges, particularly the 6.8mm Remington and 6.5mm Grendel, which meet the weight targets and are almost good enough but have been handicapped through being limited to the same overall length as the 5.56mm round in order to fit into modified 5.56mm weapons.

On paper, the 6.5mm Grendel can deliver the kind of performance identified by AMU.  However, that is only by using a long barrel and firing lead-cored target bullets.  A shorter barrel, more typical of current military practice, requires a more powerful cartridge to achieve the same performance.  Furthermore, a lead-free bullet will be longer than a lead-cored one of the same weight, thereby extending further into the case and usurping space needed for propellant; this is even more true of tracer bullets.  Finally, any new cartridge must be suitable for adaptation to a polymer/metal hybrid case to save yet more weight, but such cases are thicker and thereby reduce the propellant space some more.  Add all of these factors together and it is clear that the Grendel, while coming closer than anything else, doesn’t have enough case capacity to deliver the performance needed to replace the 7.62mm.

Where Next?
If the congressional study results in a demand for a standard infantry cartridge a new one will be needed, roughly half-way in caliber, size, weight and power between the 5.56mm and 7.62mm rounds, but with a superior long-range performance due to the use of a low-drag bullet.  Analyses of the requirements for such a cartridge keep zeroing in on a caliber of around 6.5mm and muzzle energy of about 2,500 Joules.  It would not be difficult to develop such a cartridge and adapt existing rifle and MG designs to fire it.

Despite the emphasis on the ammunition, acquiring new weapons in a new caliber would not be sufficient by itself to obtain the maximum benefit from the improvement in long-range performance.  Advanced sights will be needed, capable (as a minimum) of measuring the range and adjusting the aiming point accordingly.  Adequate training will also be needed for soldiers to get the most from the systems.

Finally, for those concerned about the cost to change to a new caliber and weapon system, it should be noted that the driver for change is the needs of the dismounted infantry.  Other branches of the armed forces could be expected to keep 5.56mm carbines in a self-defense role for the foreseeable future, and most vehicle-mounted 7.62mm machine guns also would not require rapid replacement, so the changeover could be phased over a long period.

The long-running debate over the optimum military small-arms caliber has been growing in volume in recent years, with interest in a new approach being expressed within several NATO armies.  Perhaps this congressional study will at last provide the impulse to take some practical steps to resolving this issue.

Combat experience in Afghanistan has prompted some rapid changes in the small arms carried by ISAF foot soldiers; and most especially by the U.S. Army, USMC and the British Army and Royal Marines.  The purpose of this article is to outline these changes, determine the lessons learned, and look ahead to examine the extent to which the growing variety of rifles including DMRs (Designated Marksman Rifles), carbines, IARs (Infantry Automatic Rifles) and LMGs (light machine guns) might be replaced in the future by a smaller number of weapons without losing any capability.

Developments to Date
Before the Afghan conflict began, it was assumed that most small-arms engagements would continue to take place within the traditional 300 meter limit, as they had in Iraq, and ISAF forces were equipped accordingly.  The rifles and LMGs carried by the infantry on foot patrols were overwhelmingly in the relatively short-range 5.56mm caliber, using the NATO standard SS109/M855 ammunition.  The U.S. forces used three principal weapons: the M16 rifle (favoured by the USMC), short-barrelled M4 Carbine (favoured by the U.S. Army because its compactness makes it more suitable for urban fighting, the typical scenario in Iraq) and the M249 development of the FN Minimi LMG.  Some long-range weapons in 7.62×51 NATO caliber, most notably the M240 GPMG (FN MAG variant) and also some sniper rifles and DMRs, were available for use in a support role when required.  The British patrols used the 5.56mm L85A2 rifle, L86A2 Light Support Weapon (effectively an IAR) and the L110 LMG (FN Minimi Para).  The L85A2 and L86A2 are the principal members of the SA80 family, which has had a controversial history.  As with the U.S. forces, the 7.62mm L7 GPMG (FN MAG) was available in support, and bolt-action 7.62mm sniper rifles were also in service.

These arrangements were thrown into disarray when faced with the very different circumstances of Afghanistan, where the Taliban noted the range limitation of the 5.56mm weapons and, wherever circumstances permitted, opted to engage ISAF troops from longer distances.  They could do this because as well as the ubiquitous but short-ranged AK family of assault rifles in 7.62×39 caliber, they have weapons chambered in the powerful Russian 7.62x54R round, equivalent in performance to the NATO 7.62×51.  The principal weapons using this cartridge are the lightweight PKM belt-fed LMG and the SVD semiautomatic sniper rifle.  Both the U.S. and British forces have reported that more than half of Taliban small-arms attacks are launched from ranges greater than 300 meters, out to as far as 900 meters.  While the 5.56mm NATO weapons were previously claimed to be effective out to 450-600 meters, experience has shown that their performance falls off sharply beyond 300m – or even less, when used in short-barrelled weapons.

The adoption by U.S. forces of replacements for the M855, in the form of the M855A1 EPR (U.S. Army) and MK318 Mod 0 (USMC), should resolve some other problems with the existing 5.56mm ammunition concerning erratic terminal effectiveness and poor barrier penetration.  However, these are unlikely to help the UK and other NATO nations whose lawyers tend to adopt a very literal interpretation of the Hague Convention prohibition of bullets “with a hard envelope which does not entirely cover the core” – which describes both of the new U.S. bullets.  In any case, no 5.56mm developments could achieve enough of an improvement to eliminate the need for a larger caliber to cover the longer small-arms ranges.

The immediate – and indeed, only immediately available – response of the U.S. and UK forces was to redistribute existing 7.62mm weapons to the foot patrols, despite their unsuitability in terms of weight (FN MAG) or low rate of fire (bolt-action sniper rifles).  The next stage was to launch urgent requirements for new 7.62mm weapons.  In machine guns, both the USA and UK have been developing lightened versions of the FN MAG and also adopting new lightweight MGs, comparable in weight and performance to the Taliban’s PKM.  The U.S. already has the MK48, the 7.62mm version of the FN Minimi which the British also selected in mid-2011.

U.S. Sailors use M4 carbines during small arms qualifications on the flight deck onboard the amphibious transport dock ship USS Mesa Verde (LPD 19) in the Mediterranean Sea April 28, 2011. Mesa Verde was deployed as part of the Bataan Amphibious Readiness Group and supported maritime security operations and theater security cooperation efforts in the U.S. 6th Fleet area of responsibility. (U.S. Navy photo by Mass Communication Specialist 2nd Class Josue L. Escobosa)

New rifles have been acquired; the U.S. had the advantage of already having selected the 7.62mm M110 SASS (Semi-Automatic Sniper System) and has also refurbished some 5,000 of the old 7.62mm M14 rifles as the M14 EBR (Enhanced Battle Rifle) with modern furniture and accessories.  These are proving very popular.  The British have acquired a limited quantity of a 7.62mm self-loading sharpshooter rifle from the USA, the L129A1, which is also very popular.  In contrast, the USMC has kept one eye on the needs of urban fighting and has rather controversially acquired a new, compact 5.56mm IAR to replace many of the M249s at section level; the HK 416-based M27.

The Case for Change
So we now have the following rifles and MGs in service or in prospect, all intended to be carried by dismounted soldiers on patrol: In the USA, the 5.56mm M4, M16, M27 and M249, plus the 7.62mm M14EBR, M110, MK48 and lightweight M240.  That’s a total of eight weapons, four in each caliber.  In addition they have heavier support weapons and bolt-action sniper rifles, plus Special Forces use the MK12 5.56mm and the MK17 (FN SCAR-H) 7.62mm rifles.

The UK forces have the 5.56mm L85A2, L86A2 and L110, plus the 7.62mm L129A1, L7 GPMG, and 7.62mm FN Minimi: a total of six weapons, with three in each caliber.  Again, there are bolt-action sniper rifles in use as well as these, and special forces use other rifles in 5.56mm and 7.62mm calibers.

Such a variety of weapons has obvious disadvantages in complicating and increasing the cost of acquisition, logistics, maintenance and training.  Less obviously, there may also be penalties in combat.  Those troops armed with 7.62mm weapons will be penalised by the weight of the guns and particularly the ammunition (7.62mm cartridges weigh twice as much as 5.56mm), plus the much heavier recoil in rifles which slows down aimed semi-auto fire and makes automatic fire impractical.  The bigger and less wieldy weapons are also less suited to urban fighting.  On the other hand, those with 5.56mm weapons will be able to make little or no contribution to long-range engagements – not even in supplying their ammunition to other members of their section.  When combat ranges may fluctuate rapidly it is necessary to carry weapons in both calibres to cover the tactical demands but this reduces the potential firepower of a section in both short-range and long-range engagements.

The urgent need to plug gaps in weapon capability has made the current proliferation of firearms inevitable for the time being, but this situation raises an obvious issue: when planning the next generation of weapons, is it possible to provide a similar range of capabilities with a smaller number of guns, each effective at all normal small-arms ranges?

The key question is: what capabilities do we need from infantry rifles and portable MGs?  The answer to this will determine the characteristics of the ammunition, the guns and the weapon sights.  These characteristics will also be influenced by new developments in all three fields.

I suggest that the following capabilities should be sought in new small arms, beyond the obvious ones of reliability, robustness, reliability, good ergonomics, reliability, easy maintenance, reliability, ability to accept a wide range of accessories, and of course reliability in extended combat conditions:

1. The rifle should be effective out to the maximum feasible range for small-arms engagements; at least 800 meters.  The definition of effectiveness to include hit probability, barrier penetration and rapid incapacitation of personnel.
2. The rifle should be as compact as possible, so that it is handy for urban warfare and for carrying in cramped vehicles and helos.
3. The rifle’s recoil should be light enough to facilitate training, rapid and accurate semiautomatic fire, and controllable burst fire.
4. The rifle should be capable of maintaining a high rate of fire for several minutes.
5. The LMG should use the same ammunition as the rifle, be belt-fed and be capable of accurate and sustained automatic fire out to at least 1,000 meters.
6. The guns and their ammunition should be as light as they can be without compromising any of the above requirements.

I will now consider the three elements – ammunition, guns and sights – to examine the implications of these requirements.

The conflict in Afghanistan, with its emphasis on targeting specific enemy individuals while avoiding collateral damage, features the use of weapons of high precision and limited destructive effect.  As a result, infantry small arms have a much more prominent role than that expected in conventional high-intensity warfare and this is highlighting the performance of their ammunition to a greater extent than ever before.  Now that several NATO nations have started the process of defining their requirements for the next generation of small arms, this is a rare opportunity to ask the question: Is the present combination of 5.56 and 7.62mm rifle and machine gun cartridges optimal, or could we do better?

Lessons from Afghanistan
The British Army has analysed several hundred small-arms engagements in Afghanistan over the past few years.  The results are thought-provoking.  Ever since World War 2, around 300 metres has been regarded as the normal maximum range for small-arms engagements.  However, the Taliban are equipped with PKM light machine guns and SVD rifles chambered in the old but powerful 7.62x54R Russian cartridge, and more than half of their attacks are launched from ranges of over 300 metres, with almost a quarter between 500 and 900 metres.  A report on the performance of small arms in the U.S. Army (Increasing small arms lethality in Afghanistan: Taking back the infantry half-kilometer by Major Thomas P. Ehrhart, United States Army) makes similar points.

British foot patrols were initially equipped only with 5.56mm guns; the L85A2 rifle, L86A2 Light Support Weapon, and L110A1 Minimi Para light machine gun.  However, these weapons have proved inadequate at long range.  A combination of battle experience and the testing of ammunition terminal effectiveness has led to a judgment that the rifle (which has a 20 inch barrel) is effective only up to about 300 metres and the light machine gun only 200 metres because of its short barrel of about 14 inches.  Similar findings are included in the Ehrhart report mentioned above.  What this means is that more than half the small-arms engagements take place beyond the effective range of a full-length 5.56mm infantry rifle, and about 70 percent of the engagements are beyond the effective range of short-barrelled carbines like the M4.

The second problem with 5.56mm ammunition is its lack of suppressive effect.  On most occasions when British foot patrols come under fire, they never see their attackers; the Taliban are skilled at selecting concealed positions for ambush.  So the soldiers return fire in the hope of pinning down the enemy long enough for heavier weapons to be brought to bear.  Field testing has revealed that 5.56 bullets have only half the suppressive radius of 7.62 fire, exacerbated by the fact that the little bullets are more affected by wind drift and therefore less likely to get close to the target.  This is supported by battlefield reports that the Taliban basically ignore 5.56 suppressive fire.

Estonian Army Corporal (CPL) Roman Metsatalu, assigned to the Scouts Battalion, Estonian Defense Forces, Estonian Peacekeeping Center, holds his position armed with a Vektor R6 5.56mm compact assault rifle while awaiting orders to move out on a foot patrol in Western Baghdad, Iraq. Estonian Army Soldiers are working with US Army (USA) Soldiers from 10th Mountain Division, as part of the Multi-National Corps to secure a 15-kilometer section of road in Western Baghdad, during Operation IRAQI FREEDOM.

This lack of effective range and suppressive effect are the two major concerns with 5.56mm ammunition reported by the British Army, but there have also been complaints about two other issues which have long been highlighted in the USA: erratic terminal effectiveness, even within its effective range, and poor barrier penetration.  Erratic terminal effectiveness is mainly due to the fact that the M855 bullet frequently does not yaw and upset rapidly on impact, but may instead pass right through a body point-first, inflicting a relatively minor injury unless it happens to strike a vital organ.  There is anecdotal evidence aplenty of erratic effectiveness in combat, and this has been confirmed by laboratory testing.  So have the problems with penetrating intermediate barriers such as walls or car doors and even windscreens.

These shortcomings mean that British foot patrols now carry 7.62mm weapons in place of some of their 5.56mm guns; the very effective L7 GPMG (similar to the U.S. Army’s M240) and L96 sniper rifles.  These weapons are not ideal, as the rifles are bolt action with a low rate of fire and the GPMG is very heavy.  This is most unwelcome given that reducing the burden (typically around 100 lbs) worn and borne by the infantryman is one of the top equipment priorities of the British Army.  The British are following U.S. practice in adopting a semiautomatic 7.62mm sharpshooter rifle (ordered from the American company Law Enforcement International and designated L129A1) and also in seeking lighter 7.62mm machine guns; namely a lightened version of the GPMG and also an even lighter 7.62mm LMG which will match the characteristics of the Russian PKM.

Do We Need a New Cartridge?
Given that we are now adopting a mix of 5.56mm and 7.62mm weapons at section level, what’s the problem?  The 7.62mm guns can deal with the long-range countryside work, with the 5.56 mm retained for urban fighting.  One problem with this is that it may not be possible to draw neat lines around scenarios: a section may be clearing houses in a village at one moment then come under long-range fire as they leave.  It also means that those carrying 7.62mm weapons will be badly equipped for the close-quarter battle, while those with 5.56mm guns will be unable to participate in long-range engagements, thereby reducing the effective firepower of the section in each case.  Finally, it still leaves us with the erratic terminal effectiveness and poor barrier penetration of the 5.56mm M855, along with the 7.62mm’s ammunition weight and recoil.

Various attempts have been and continue to be made to uprate the performance of the 5.56mm cartridge, the most recent being the MK318 Mod 0 which has been adopted by the USMC, and these offer some improvements in terminal effects and barrier penetration.  However, they involve technologies such as open-point and/or fragmenting bullets, which are regarded as unacceptable by the British and probably other NATO countries.  In any case, the degree of improvement is fundamentally limited by the small size and modest power of the cartridge.

The problem with the 7.62×51, at least in its standard M80 ball loading of 147 grains at 2,700 fps, is that it is effective but not efficient.  The bullet does not usually yaw very rapidly on impact; in fact gel tests indicate that some smaller calibres can inflict more severe wounds.  Also, it has an unimpressive long-range performance for its calibre due to the relatively light bullet which sheds velocity quite quickly.  The cartridge is effective simply through its raw power and bullet size, but these have a cost in weight (double that of the 5.56mm) and recoil (three to four times the recoil energy compared with 5.56mm rifles of similar weight).  The heavy recoil makes training more difficult, slows down double-tap shooting and makes automatic rifle fire virtually uncontrollable.  The ballistic characteristics can be improved by using a heavier and better-designed bullet than the M80, but at the cost of even more ammo weight and recoil, which is definitely not what is wanted.

The MP9
The MP9 has been developed from the Steyr Tactical Machine Pistol or TMP, to which Brügger & Thomet acquired the rights in the early 2000s.  This innovative Swiss company has made a number of modifications, the most obvious being a side-folding shoulder stock, which transforms the steadiness of aim and the effective range.  They have also added a NATO accessory rail on top for optical sights, ghost ring rear sights with an adjustable foresight, a trigger safety (similar to the Glock system), a suppressor attachment on the barrel sleeve (B&T also make the suppressors), and translucent magazines for 15, 20, 25 or 30 rounds.  Options include a Picatinny rail under the barrel in lieu of the fixed handgrip, and a fixed skeleton rather than folding stock.  The standard colour of the body is black but green and coyote tan are also available, as is a blue version adapted to fire Simunition FX training ammunition (which can also work with the new Force on Force cartridge recently introduced by ATK) and a red “manipulation” gun which cannot fire live ammunition and is used for safe handling training.

The result is an exceptionally compact and lightweight submachine gun or machine pistol, largely made from polymer and weighing just 1.4 kg (3.1 lbs) empty.  Loaded 9mm magazines weigh 240 grams (8.5 oz) for 15 rounds to 440 grams (just under 1 lb) for 30 rounds.  The MP9 is 303 mm (11.9 inches) long with the stock folded and 523 mm (20.6 inches) with the stock unfolded.  Barrel length is 130 mm (5.1 inches).  Unlike most SMGs (with the notable exception of the Heckler & Koch MP5 series) the gun fires from a closed and locked bolt, utilising a rotating barrel locking system; it will still fire when the muzzle is pressed against the target.  The cyclic rate of fire is 750-800 rpm.  The single shot/automatic selector and manual safety switch is a push-button by the thumb.

PDW cartridges, from left to right: 5.7x28 FN, 4.6x30 HK, 9x19 NATO, and three loadings of the 6.5x25 CBJ; saboted ball, HET and frangible.

According to B&T, about 5-6,000 MP9s are sold every year.  The gun is widely exported and is now in service with many special forces and close protection teams.  The use of the ubiquitous 9mm cartridge is a significant selling point, along with the compact dimensions, the open holster (the gun clips into it) and the availability of the training versions.  The modest penetration of 9mm ammunition isn’t felt to be an issue as hardly any of the expected opposition use body armour (this may not, of course, remain the case indefinitely), and around 50m is regarded as an adequate range for its particular role.

The nearest competitor to the MP9 is the Heckler & Koch MP7.  The most obvious difference between them is that the MP7 is available only in HK’s unique 4.6×30 caliber, whereas the MP9 fires the 9×19 NATO, aka Parabellum or Luger, which is readily available from many manufacturers in a very wide range of loadings.  At least, that was the case until recently, when the first example of the B&T MP9 in the 6.5×25 CBJ version appeared.

The 6.5×25 CBJ
Carl Bertil Johansson is an experienced gun designer who has worked with Aimpoint and SAAB Bofors among others, but set up CBJ Tech to develop his idea for a high-performance cartridge.  The company, a family-run business, is based in southern Sweden and owns a Cold War bunker which provides very secure accommodation for workshops and range testing.

CBJ started development of the 6.5×25 cartridge in the late 1990s, at the time of the NATO competition to select a new PDW round.  This was intended to replace the 9×19 with longer-ranged ammunition able to penetrate NATO’s CRISAT target (equivalent to contemporary Russian body armour) at 150 metres.  The only cartridges officially tested were the 5.7×28 FN developed for the P90, and HK’s 4.6×30 for the MP7.  It proved impossible to reach political agreement on which to choose, so no decision was made.

Test results in ballistic gel, 340mm (13.4 inches) wide (bullet track from left to right): 9mm NATO ball (top), 6.5mm CBJ ball (middle), 6.5mm CBJ HET (bottom).

FN and HK both started with “clean sheet” ammunition and gun designs, but Carl Bertil decided on a different approach, reasoning that a cartridge that was interchangeable with the universal 9×19 round by means of a simple barrel swap would have a much wider appeal.  It would mean that existing guns could be adapted to fire the new cartridge, and also that guns in the new caliber could be easily changed to 9×19 if required; even the magazines remain the same.

This design principle meant that the new CBJ cartridge would have the same overall dimensions as the 9×19 (including the rim diameter) and would need to develop a comparable recoil impulse to ensure reliable gun functioning.  The cartridge that emerged from this study was the 6.5×25, with an extended, necked-down case and a short bullet protrusion.  Several different loadings in three ballistic groups have been developed.

To compete with the 5.7 and 4.6mm rounds in meeting the NATO PDW long-range penetration requirement, a sub-caliber loading is used.  The standard military “ball” loading is actually a 4mm caliber tungsten bullet in a plastic sabot.  The bullet weighs 2 g (31 grains), 2.5 g with its sabot.  There is a “spoon-tip” version designed to encourage more rapid bullet upset on impact, and a training variant using cheaper core material.  All of these are fired at a muzzle velocity ranging from 730 m/s (2,395 fps) from a 127mm (5 inch) barrel (the recommended minimum barrel length) to 900 m/s (2,950 fps) from a 305mm (12 inch) barrel.  The tungsten-cored loadings fired from a 12 inch barrel match the trajectory of the 5.56×45 NATO from an M4 Carbine and have much superior penetration to its standard SS109/M855 ammunition, being able to punch through 9mm armour plate.  From a 12 inch barrel, velocity at 300 metres is 578 m/s (1,900 fps) at which range it will still penetrate the CRISAT target.

The 6.5mm version of the MP9 has the barrel extended to 150mm (5.9 inches), giving a muzzle velocity of just over 800 m/s (2,620 fps).  By comparison, the 5.7×28 P90 and 4.6×30 MP7 both fire as standard 2 gram (31 grain) bullets at about 720 m/s (2,360 fps).  A brass-jacketed 6.5mm ball round weighs 7.5 grams (115 grains) compared with 6.2-6.4 grams (96-99 grains) for the 5.7 and 4.6 rounds and around 12-13 grams (185-200 grains) for 9mm.  Loaded 15 and 30 round 6.5mm MP9 magazines therefore weigh about 165 and 290 grams (5.8 and 10.2 oz) respectively.  Steel and light-alloy cases are being considered by CBJ, but the initial emphasis is on brass.

The other ballistic groups fire full-caliber 6.5 mm bullets.  One group, primarily intended for police use, fires lightweight 2.5 gram (38.6 grain) bullets at the same velocities as the sub-caliber loadings.  These consist of the HET (high energy transfer) brass bullet and a frangible (polymer/metal powder blend) version for use in training or when barrier penetration needs to be minimised.  The HET will also penetrate the CRISAT armour target at short range, but these rounds are most effective within 50 metres as the lightweight bullets rapidly lose velocity.  The third ballistic group has just one round – subsonic armour piercing – intended for use with a suppressor.  It is much heavier than the other bullets at 8 grams (123 grains) and can also penetrate the CRISAT target.

MP9 stripped down to show both barrels.

The 6.5×25 cartridge cases were previously made by reforming 9×29 Winchester Magnum brass, but CBJ Tech now has cases specially made for them.  These use slightly thicker brass, requiring some adjustment to the propellant loads.  The colour of the sabots has not yet been firmed up; originally these were black but this was changed to white to aid recovery from the indoor range’s backstop, which has an outer layer of shredded black rubber.  For production purposes, different colours may be used to indicate the loading.

SAAB Bofors was initially involved in helping to market the 6.5×25 while the NATO competition was running, but is no longer involved with the project.  CBJ Tech is continuing to develop the ammunition and demonstrate its capability in a wide variety of converted submachine guns and pistols.  Those tested to date range from the Steyr AUG SMG to SIG Sauer and Glock pistols.  Where necessary, pistols are fitted with barrels extended to 5 inches.  A substantial purpose-designed SMG, the CBJ MS, was initially developed to use the new round and features a folding bipod and an optional large-capacity drum magazine in order to act as a light support weapon out to 400m.  However, CBJ Tech is now mainly focused on adapting existing 9mm weapons, particularly the MP9 as this is seen as the ideal combination for the PDW role in which there is growing military interest.  The remarkable performance of the 6.5mm cartridge, especially in armour penetration, is such that CBJ is intending to offer their conversions only to military and police customers.

How it Works Together: the MP9 in 6.5×25 CBJ
Once in Sweden, I had the opportunity to test-fire the MP9 in both 9mm and 6.5mm calibers alongside other weapons for comparison purposes, in two locations; an outdoor range in semiautomatic fire and in CBJ’s indoor range on automatic.  Before this, I had only been able to handle the MP9 so I was keen to see how it performed.

In either caliber the MP9 is a pleasure to shoot.  I found the spacing between the butt, the pistol grip and the forward handgrip suited me well.  The fat, forward-sloping front handgrip greatly aids control and I would certainly not wish to do without it.  For semiautomatic fire, the little 1.5x Trijicon sight proved ideal and the effective range of the 6.5mm version firing the saboted tungsten ammunition would probably be around 200 metres.  In 9mm calibre, or for close-range work, a 1x holographic red-dot sight (also tried) might be preferred.

The author firing the MP9.

Given the MP9’s small size and weight I was surprised by its controllability in automatic fire.  As a UK civilian, my opportunities for firing automatic weapons are more or less zero but I found no trouble in keeping the rounds on target when firing short bursts; the little gun was much easier to control than an M16 I tried afterwards.

There was very little difference between firing the 9×19 and 6.5×25 versions of the MP9.  Subjectively, the 6.5mm version felt as if it had slightly less recoil.  My arrival coincided with CBJ’s working up of loads using their new cartridge cases.  They hadn’t finalised this process and the 6.5mm version suffered some failures to feed with the new cases (although it performed very well with the older ones) but that was expected to be a temporary glitch.

A key question in my mind was this: OK, the little 4mm tungsten bullet goes through armour like the proverbial hot knife through butter, but how does it perform against unarmoured personnel?  This question could only finally be decided in combat, of course, but ballistic gel provides a repeatable substitute for testing purposes.  CBJ Tech have the facilities for this, and performed some tests for my benefit.  I witnessed three different cartridges being compared at about 5 metres range; the standard 6.5mm saboted ball (this one first had to penetrate a CRISAT target), the full-caliber 6.5mm HET and the 9×19 NATO FMJ.  The least impressive was the 9mm, while the 6.5mm HET showed far more disruption with rapid bullet upset.  The saboted ball also performed significantly better than the 9mm, and according to previous tests I was shown, the spoon-tip version demonstrates even faster upset as one would expect.  Interestingly, on one of the test shots of the saboted rounds the sabot was found stuck into the surface of the gel block, which showed that it had followed the bullet down-range quite closely.

9mm thick armour plate from a Russian vehicle, showing penetration by 6.5mm CBJ ball.

In summary, the Brügger & Thomet MP9 is arguably the best of the new breed of PDWs – or machine pistols or compact SMGs if you prefer.  For only about double the size and weight of a pistol (but half the size and weight of an M4 Carbine) it offers perhaps ten times the effective range plus controllable automatic fire.  The use of universally-available 9×19 ammunition is proving to be an important benefit, but if more range or penetration is required the gun can easily and reversibly be converted to the impressive and versatile 6.5×25 CBJ.  For any military or law enforcement organisations contemplating a weapon in this class, this could be a winning combination.

More information about the 6.5×25 ammunition is presented on the CBJ Tech website at: www.cbjtech.com.  Brügger & Thomet’s website is: www.brugger-thomet.ch/.

Anthony G Williams is an independent ammunition consultant and co-editor of Jane’s Ammunition Handbook.  He maintains a website at www.quarry.nildram.co.uk.

There has long been a requirement for a personal defence weapon, or PDW, for soldiers whose primary duty does not involve carrying a rifle.  They need something much smaller, lighter and handier which does not burden them or distract them from their main task.  Originally, the main priority was for officers, who were almost invariably given revolvers or pistols; but handguns also found a place with cavalry and, later on, with soldiers such as gunners who might come under infantry attack or with tank crews whose space was at a minimum.

The Second World War saw extensive use of submachine guns chambered for pistol ammunition in both offensive and defensive roles, although they were not primarily intended as PDWs.  While shorter than a rifle, they were often almost as heavy and troublesome to carry.  A commendable effort to find a better solution was made by the US Army, resulting in the adoption of the light and handy .30 M1 Carbine chambered for a much smaller and less powerful cartridge than the M1 Garand rifle.  This was so successful that it was often used in more offensive roles than originally intended, especially in its selective-fire M2 version, leading to some criticisms of the effectiveness of its ammunition.  However, neither SMGs nor the Carbine replaced pistols, which remained in service alongside them.

STK CPW. (Courtesy of Maxim Popenker)

A major change came with the adoption of small arms chambered for small-caliber high-velocity ammunition, the first and by far the most common cartridge being the 5.56×45.  Its adoption by the USA in the 1960s, and by the rest of NATO in the 1980s, largely killed off the military use of both the .30 Carbine and most SMGs.  Rifles and especially carbines in 5.56mm were lighter and handier than traditional SMGs while being a lot more effective.  They even replaced pistols to a great extent in many armies, although the US Army has remained an exception.

While the standard NATO pistol/SMG cartridge has always been the 9×19, also known as the Parabellum or Luger, early experiments were also made with small-caliber compact cartridges.  Among the many tried from the 1950s to the 1970s, three are particularly notable: the .22 APG, Colt .22 Scamp, and Colt .221 IMP.

Service PDW rounds, from left to right: 5.56mm NATO, .30 Carbine, 9x19, 9x21 Russian AP, .40 S&W, .45 Auto, 5.7mm FN, 4.6mm HK and 5.8x21 Chinese.

The .22 APG (Aberdeen Proving Ground) was an M2 Carbine rechambered for a new 5.56×33 cartridge.  This round was not a necked-down .30 Carbine but was based on a wider case, and it fired a 41-grain bullet at around 3,100 fps.  This was only for comparative test purposes as a part of Project SALVO in the 1950s, but the other two were serious attempts at producing different kinds of personal defence weapons at the end of the 1960s.

The Colt .22 Scamp (Small Caliber Machine Pistol) was chambered for a 5.56×29 cartridge which fired a 40-grain bullet at 2,100 fps.  The gun was basically a big pistol, gas-piston operated and with a plastic receiver to minimize weight, and was marketed, without success, as a .45 M1911 replacement.  It could fire semi-auto or three-shot bursts at a cyclic rate of 1,500 rpm.

The Colt .221 IMP (Individual Multi-Purpose weapon) was initially chambered for an existing commercial cartridge, the .221 Remington Fireball designed for the big, bolt-action XP-100 pistol, and fired a 52-grain bullet at 2,500 fps.  The ultimate version was intended to use a .17 cartridge firing a 25-grain bullet at 3,000 fps.  It was developed at the request of the USAF who wanted a survival weapon, and was subsequently designated GUU-4/P.  The gun had a most unusual layout; it was a bullpup without provision for a forward handgrip, the pistol grip being located close to the muzzle.  The shooter was expected to steady the weapon by holding the receiver against his forearm with his non-firing hand, which led to the nickname “arm gun”.  Like the Scamp, this made no progress although the layout was adopted for the 5.56mm Bushmaster Armpistol.

.30 M2 Carbine. (Courtesy of Maxim Popenker)

During the early 1990s, NATO became concerned that potential enemies were starting to issue body armor to their troops, which the 9mm ball rounds were unable to penetrate.  As a result, a competition was arranged for a replacement for the 9mm which would have to penetrate a specified level of body armor (named the CRISAT target for the Collaborative Research Into Small Arms Technology project), defined as a 1.6mm titanium plate and 20 layers of Kevlar, while retaining sufficient energy to incapacitate the man wearing the armor, out to a range of 150 metres.  Two different weapons were envisaged for this ammunition; a short-range (50 m) PDW weighing less than 1 kg (effectively a pistol) and a medium-range (150 m) close defence weapon weighing less than 3 kg (a compact SMG).

The penetration requirement forced the adoption of a small-caliber cartridge firing a high-velocity steel-cored bullet.  The first contender was FN’s 5.7×28 round, as chambered in the P90 SMG and subsequently the Five-seveN pistol.  The standard SS190 ball uses a 31-grain bullet fired at 2,350 fps (from the P90).  The ammunition is lighter and smaller than the 9×19, allowing the pistol magazine to hold 20 rounds, and the P90 to carry 50.  Recoil is also lighter than either the 9mm or the 5.56mm, making the weapons easier to shoot accurately.

The 5.7mm FN was subsequently challenged by Heckler & Koch who introduced their 4.6×30 cartridge at the end of the 1990s, initially available in the MP7 machine pistol (with the P46 pistol intended to follow).  The current standard ball loading is the Ultimate Combat, which fires a 31-grain bullet at 2,360 fps (heavier than the original 26-grain Combat Steel).  Various trials of the two cartridges were held between 2000 and 2003 and, while both met the requirements, the FN round generally came out ahead.  However, the necessary consensus between NATO countries proved impossible to achieve so no standardisation has taken place: it is left to each country to make its own choice.

The Russian 9mm PP-2000. (Courtesy of Maxim Popenker)

The Chinese apparently followed the same line of thinking as they introduced a new 5.8mm round for pistols and SMGs.  This has the same calibre as their new rifle/MG cartridge, but the case is only 21mm long instead of 42mm, and is more slender.  Performance is modest, but the relatively heavy bullet provides good penetration.

Other similar cartridges have emerged in recent years, so far without commercial success, such as the British .224 BOZ (10mm Auto necked-down, offered in a Glock 20 pistol), the Czech .17 Libra (based on a rimless version of the .22 Hornet case and chambered in a conventional SMG-type PDW), the Swiss Tuma MTE .224 VA (based on the 7.62×25 Tokarev case and offered in a machine pistol), the .225 JAWS (developed by Wildey for the Viper pistol on behalf of Jordanian Armaments and Weapon Supplies, with the same case diameter as the .45 ACP; .250, .300, .350 and .400 versions were also made) and, last but not least, the Swedish 6.5×25 CBJ, of which more later.

To date, the 5.7mm P90 and 4.6mm MP7 have achieved only modest military sales, mainly to specialised units rather than for use as general-issue PDWs.  This means that the most common combination of self-defence weapons in Western service remains a short-barrelled carbine in 5.56mm (or equivalent) caliber with a self-loading pistol.  However, there are problems with both of these weapons when used as PDWs which have been highlighted by the conflicts in Iraq and Afghanistan.  These theatres lack front lines behind which soldiers can feel safe; attacks can come anywhere at any time.  This means that all soldiers, including transport drivers and others who would not normally expect to be in a combat zone, need to be able to defend themselves.