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A wide variety of ammunition choices is available for military small arms, a category which encompasses man-portable, non-crew served weapons such as pistols, assault rifles, submachine guns, sniper rifles, light machine guns, squad automatic weapons and shotguns.

In recent decades, small arms munitions (with the exception of shotgun ammunition) have taken the form of copper-encased bullets with a lead core and a penetrator tip made of a harder material such as steel or tungsten alloy. The bullet is seated halfway inside a brass casing, with the bottom portion of the casing filled with propellant. A primer is placed at the bottom of the cartridge to initiate combustion of the propellant.

Experience in recent operations, such as the two-decade-long conflict in Afghanistan, has led to some criticism of currently fielded NATO-standard ammunition, especially the 5.56mm round used in most European and US rifles. Many many soldiers report that the 5.56 has displayed inadequate range and stopping power. Currently, armed forces are attempting to retain or gain a battlefield edge by introducing new types of small arms ammunition, including the utilization of alternate materials.

Green Ammunition

The 5.56 M855A1 Enhanced Performance Round, shown here, is sometimes called a ‘green round’ due to its copper-only core. It has proven more effective against hard targets than the 5.56 M855 round it is designed to replace. The new round is equal to the M855 round against soft targets in terms of effectiveness but is more consistent in its performance. (Photo: US Army)

A major development over the past decade has been the introduction of environmentally friendly small arms ammunition in 2010. Surprisingly to many, the US Army took a leading role here, replacing its copper jacketed, lead core M855 assault rifle ammunition with the lead free M855a1 EPR (Enhanced Performance Round). The new 5.56mm ball bullets have a copper jacket and solid copper core. The bullet’s top half or penetrator is made of hardened steel. To compensate for the lower weight of the projectile’s core, the new bullet is three millimetres longer than the original M855 to achieve the same 62 grain weight. The M855A1 also uses a new propellant, which burns faster than the older bullet’s powder, creating higher muzzle velocity while reducing flash. The bullet is compatible with the M4, M16 and Heckler & Koch assault rifles as well as the M249 machine gun. The lead free 7.62mm M80A1 bullet was introduced in 2014.

Environmental contamination of training grounds and firing ranges through lead munitions was the initial motivation for exploring so-called ‘green munitions’ alternatives to lead core bullets. However, operational experience in Afghanistan and Iraq demonstrated that the new munition actually displayed superior effects. “What started as a programme to be more environmentally friendly became a significant upgrade in military small arms capability,” wrote Major (now Colonel) Glenn Dean, who had participated in the leadless-bullet development programme, in his 2011 e-book ‘In Search of Lethality’.

Soldiers reported that the new bullets were better at penetrating protective barriers and in incapacitating enemies than the softer-core ammunition. This field experience confirmed the data gathered during testing of the new munition. The steel-core bullet can penetrate a 3/8-inch-thick steel barrier at twice the distance of the lead-core munition. The new 5.56mm bullet can also penetrate concrete masonry at a distance of up to 75 yards, while the old bullet could not penetrate concrete at any range. When striking soft targets, on the other hand, the M855a1 will yaw sooner than the original ammunition, making it more likely to consistently inflict significant trauma, thereby enhancing stopping power. The original M885, by contrast, would – under certain circumstances – fly straight through an enemy soldier while producing less kinetic effect on the target. This was especially the case during close-quarters combat in urban or cave-clearing operations.

Some negative factors include greater wear and tear on rifle barrels, bolts and magazines. To this end the US Army also developed a special ‘green magazine’ for the new munition. After initial doubts, the US Marine Corps also adopted the M855a1 in 2017. European firms such as Germany’s MEN-DefenseTec and Norway’s Nammo are also producing lead free munitions in NATO standard calibres 5.56×45 and 7.62×51. According to Nammo, these have been purchased by the armed forces of several European countries.

“New” Calibres

Some armed forces are experimenting with unconventional calibres. Fiocchi, Nammo and RUAG, for instance, all offer ball and armour piercing ammunition as small as 4.6mm for submachine guns and personal defence weapons, such as the Heckler & Koch MP7.

The US Special Operation Command (SOCOM) has introduced a new sniper ammunition, the 6.5mm Creedmoor round. At 125 grains, the projectile is only marginally lighter than the 130 grain 7.62x51mm round, but the new munition is notably longer and slimmer, enhancing long-range performance. Joint testing by SOCOM and the US Army determined that – when compared to the current 7.62mm round – the new round had twice the hit probability at a range of 1,000 metres. The Creedmoor also displayed a 33% greater effective range, a 30% increase in energy on target, a 20% higher velocity at 915 metres, a 40% decrease in wind effect on the bullet’s trajectory, and a reduced recoil. The formal decision to introduce the Creedmoor – which was developed approximately ten years ago – was taken in March 2018. A presolicitation notice was issued in October 2019 for a conversion kit to replace the upper receiver for the current 7.62mm M110 Semi-Automatic Sniper System (SASS). Conversion of the SASS inventory to the 6.5mm calibre is expected to be completed by 2023.

Nammo and US company MAC LLC are together offering .50 cal ammunition with lightweight polymer cases. (Photo: MAC LLC)

The US Army is currently developing a new family of infantry weapons to be fielded in 2023. This Next Generation Squad Weapon (NGSW) programme includes a new assault rifle, submachine gun, SAW, marksman or sniper rifle, pistol and shotgun. The rifle and SAW are to be fielded with a unitary 6.8mm calibre. This ‘intermediate’ sized round is intended to offer significantly better ballistic performance (extended range and accuracy, controllable recoil) than 5.56mm projectiles, while weighing less than the 7.62mm round. “We’re looking to reach out around 600 metres and have lethal effects even if the target is protected by body armour,” Colonel Geoffrey Norman, Force Development Division Chief at Headquarters, US Army, said in a press interview in February 2018. “We need to have lethal effects against protected targets and we need to have requirements for long-range lethality.” Then Army Chief of Staff General Mark Milley declared in October of 2018 that the round would have an accurate range “far in excess” of any assault rifle munition currently in service.

Notably, this is not the first effort to reduce weight and enhance performance by using a 6.8mm projectile. The .276 Pederson round was successfully tested by the US Army in the 1920s, but was rejected on logistical grounds (the Army still retained large stockpiles of .30 calibre or 7.62 munitions left over from World War I). SOCOM and Remington Arms developed the 6.8 Remington SPC round in 2002-2004 in an effort to overcome the various deficiencies of the NATO standard 5.56mm and 7.62mm calibres. At the time, the 6.8mm round was found to be effective for urban combat settings, but displayed poor performance at longer distances. The US armed forces decided in 2007 not to procure the 6.8mm calibre, although Jordan and Saudi Arabia subsequently did introduce the munition.

Caseless and Telescoped Ammunition

A cased-telescoped lightweight ammunition belt (Photo: US Army)

Two of the three remaining contenders in the NGWS programme are presenting unconventional case designs to further reduce the weight of the 6.8mm ammunition.
General Dynamics is teaming up with True Velocity to develop a composite cased cartridge. True Velocity currently produces and markets military grade composite ammunition in 5.56mm, 7.62mm, .338 (8.5mm) and 12.7mm calibres. The ammunition is composed of a steel case head and a composite case body. The composite casing is 50% lighter than a conventional brass case. The fully loaded bullet is still 30 per cent lighter than a conventional cartridge. According to the manufacturer, the composite casings also display superior heat dispersion inside the weapon’s chamber, thus reducing heat stress on the rifle and also minimising muzzle flash.

Textron takes a different approach. The firm plans to offer cased-telescoped ammunition (CTA) in the NGWS. CTA uses a plastic or polymer cartridge case instead of a brass case. The US Army has been studying CTA technology for a decade with an eye to developing a lightweight family of munitions, with Textron conducting the Cased Telescoped Small Arms Systems programme for the US Department of Defence.

The 4.73x33mm caseless ammunition used in the G11 rifle (which never entered into service), shown disassembled. The components are, from left to right, the solid propellant, the primer, the bullet, and a plastic cap that serves to keep the bullet centred in the propellant block. (Photo: via author)

The CTA projectile is normally completely enclosed in the case, together with the propellant. The casing is sealed with a flat top like a shotgun shell. This configuration has earned the technology the moniker ‘lip-stick’ ammunition. CTA munition is generally not only lighter but much shorter than conventional brass-cased munitions. Therefore, the case is somewhat thicker than a conventional cartridge. For this reason, Textron proposes a 20 round magazine for the NGWS assault rifle. A belt-fed system for the prospective LMG/SAW has also been developed.

Textron already offers CTA in the 5.56 and 7.62 calibres as well as in 6.5mm. The firm introduced the 6.5 variant on their own initiative in 2017, describing it as 35 per cent lighter weight but 30 per cent more lethal than the standard 7.62×51 round. Compared to the 5.56mm round, the 6.5mm CTA has three times the energy downrange, according to a Textron statement. This would translate to significantly greater range and stopping power. The CTA programme is currently at Technology Level seven, which signifies that the prototype is performing at or near the requirements for an operational system.

Caseless munitions have also been proposed as one way to reduce infantry weight load. The term ‘caseless’ is somewhat of a misnomer as this type of ammunition – which closely resembles CTA rounds – does enclose the projectile in a case. The difference is that the cartridge case actually consists of a solid propellant (such as nitrocellulose) with the primer and bullet firmly lodged inside. Advantages such as low weight and no spent casings are, however, offset by the technical complexity of the concept. There are currently no active programs to develop military-grade caseless ammunition.

Supercavitating Ammunition

Comparison of the standard 7.62x51mm round with Cased Telescoped Ammunition in three calibres. (Photo: US Army)

Supercavitating bullets are a special category of ammunition. Used by special operations forces, these projectiles are effective even when fired underwater or fired from above water at submerged targets. The supercavitation effect is created by placing a comparatively rounded but sharp-edged tip on the projectile. This displaces water ahead of the bullet, creating an air bubble, which extends along the sides of the projectile, significantly reducing friction and drag.

The Norwegian manufacturer DSG has been pursuing supercavitation for the past decade. It introduced prototype munitions as early as 2011, but has only recently reached the stage where serial production is viable. The firm is now actively marketing its Cav-X family of small arms ammunition which is available in 5.56x45mm, 7.62x51mm, .300 BLK and 12.7x99mm. Several calibres are available in standard and armour piercing variants. Cav-X is currently being evaluated by the US Special Operations Command, which would represent the largest single potential customer for the Norwegian firm. DSG states that the ammunition is already being procured by other unidentified governments.

DSG describes Cav-X as a Multi-Environment Ammunition, suitable for engaging targets that are above water, partially submerged or fully submerged. The ammunition can be fired in four distinct modes: conventional engagement with both the shooter and the target being outside the water; underwater engagement, with both the shooter and the target being submerged; engagement of submerged targets by shooters who are outside the water; and the precisely reversed scenario where divers fire at targets which are above the surface. All rounds can be fired against human targets (where the supercavitating properties enhance trauma, increasing the likelihood of death or incapacitation). Armour piercing rounds can also be used against torpedoes, submerged mines, unmanned underwater vehicles, and even against manned submarines operating in shallow waters.

.223 Remington cartridge on the left and a 4.73x33mm caseless cartridge on the right (Photo: via author)

Cav-X munitions are available in two variants: A2 and X2. The A2 variant is produced in all of the previously stated calibres. These rounds must be fired from outside the water, but can engage submerged targets. The A2 variant is designed for rifles and machine guns deployed on boats, helicopters, or at the water’s edge. The X2 load is designed for combat swimmers and other special operations personnel who operate There has also been speculation about arming UUVs with this ammunition. These bullets can be fired from submerged positions against targets that are either under water or above water. X2 rounds are currently available in 5.56x45mm, 7.62x51mm, and .300 BLK calibres. When fired from near the surface, these munitions could have sufficient momentum to attack low-flying helicopters and UAVs.

The new ammunition is designed to be compatible with the majority of firearms currently in service with NATO armed forces. According to DSG, Cav-X rounds achieve effective underwater ranges between 12-14 metres (5.56mm and 7.62mm) and 60 metres (12.7mm) against soft targets. Alternately, during testing performed by the company, the 12.7mm variant has penetrated two centimetres of steel after passing through 17 metres of water.

Sidney E. Dean is President of Transatlantic Euro-American Multimedia LLC. and a regular  contributor to ESD.