Calibre conundrums – developments in small arms ammunition

Small arms represent one of the most fundamental elements of military equipment. As such, one might expect that these weapons and their accompanying ammunition have benefitted from years of significant technological advances, though such an expectation would only partially ring true. Significant technological progress has indeed taken place, but many widely used types of small arms ammunition have remained basically unchanged for many years. However, it looks less certain whether this trend will continue.

There are very few military systems that remain in service, materially unchanged, for more than 130 years, but that is the case in terms of one widely-used ammunition calibre. The story starts in the 1880s as the then Imperial Russian Army was looking to acquire a new rifle. The 1880s were a time of revolutionary change in small arms, with the primary catalyst being French chemist Paul Vieille who had developed smokeless powder in 1884. This was designated as ‘Poudre B’ by the French military and led Lt Col Nicolas Lebel to rework the existing 11 × 59 mm Gras cartridge to create the 8 × 50R mm Lebel cartridge known as the Balle M, to be used in his Model 1886 Lebel rifle adopted by the French Army.

Prior to the invention of smokeless powder, black powder was used as the propellant for cartridges, causing a large amount of smoke to be released on firing. Smokeless powder was far more efficient, delivering more velocity and more range, with the lack of smoke also helping to improve shooter accuracy. As the new propellant was more powerful, it also allowed the use of smaller calibre cartridges. Moreover, it rendered most in-service rifles obsolete and led to a wave of new rifle acquisitions across Europe.

The Russian response to this was a competition for a new rifle and a new round to fire from it. Two designs reached the final phase of the competition, one from a Russian Captain Sergei Ivanovich Mosin and the other from a Belgian, Léon Nagant. The Russians decided to combine the best features of both designs into as single new weapon known as the Mosin-Nagant, a bolt action rifle, with a five-round magazine, using the 7.62 × 54R mm cartridge. The rifle entered production in the mid-1890s, with the first examples actually produced in France, before production in Russia commenced. Production of the rifle eventually came to an end in the Soviet bloc and China in the early 1960s.

As to the 7.62 × 54R mm round, its adoption as the standard rifle round of the Imperial Russian Army also made it the de facto machine gun round. This situation continued into the Soviet era, with efforts in the 1930s to develop a semi-automatic rifle using the 7.62 × 54R mm round, part of a desire to generate more infantry firepower. In the end, the firepower demand was met by a new generation of weapons using a new 7.62 × 39 mm intermediate round. The semi-automatic SKS carbine was supposed to replace the Mosin-Nagant and originally the AK-47 was seen as a sub-machine gun replacement. Ultimately, it was decided that the AK select-fire assault rifle would become the standard infantry weapon rather than the carbine.

The 7.62 × 54R mm round remained in service as a machine gun round, as it does to this day. It even found a new application for what we would now call a designated marksman rifle (DMR), which saw the development of the SVD rifle by Dragunov designed to offer range coverage from 600 to 800 m, and which could not be adequately covered by the AK. The SVD came into service in the early 1960s and remains a first-line service weapon with Russia and many other militaries around the world. Supposedly, the SVD is due to be replaced by the Chukavin SVCh, which will also use the 7.62 × 54R mm round. It is truly extraordinary that this round has outlasted two empires, the Tzarist Russian and the Soviet; there is no doubt at this point that it will achieve a service life well in excess of 150 years!

Pistol longevity

Georg Luger (1849–1923), the Austrian designer of the famous Luger pistol, left an ammunition legacy that continues into the modern era with a standard NATO round. Initially, the Luger pistol was chambered in 7.65 × 21 mm (7.65 mm Luger), but the Imperial German Navy, while liking the pistol, were not convinced by the 7.65 mm round. This led Luger to develop a new round in 1902, the 9 × 19 mm Luger, now more commonly referred to as 9 mm Parabellum, and in 1904 the Imperial German Navy adopted the pistol in that calibre, with the Imperial German Army following suit in 1908.

Numerous pistol rounds were available in Europe and the US when Luger designed the 9 × 19 mm and many rounds have been developed since. It is a tribute to the excellence of Luger’s 9 × 19 mm design that this round still dominates the pistol scene some 122 years after it was originally developed. From pistols, the 9 × 19 mm would go on to become the standard for Western sub-machine guns, a position that it still retains.

Efforts were made to find a replacement for the 9 × 19 mm round with NATO generating a requirement for such a round to be used by a new category of weapon known as the personal defence weapon (PDW) during the 1980s. The objective was to have a new weapon in two formats, one handheld – that would replace the pistol – and a shoulder-fired system to replace the sub-machine and standard carbines and rifles used by support troops. The new round for these weapons would offer higher accuracy, greater range and superior penetrating power than the 9 × 19 mm round. Part of the specification called for the new round to have the capability to defeat body armour.

Winning the NATO PDW requirement had immense potential, since at this point the Cold War was still active and the task to replace pistols, sub-machine guns and other weapons in second-line roles across NATO presented an extraordinary possibility. One of the first to respond to the NATO requirement was FN Herstal, a company that had developed a new 5.7 × 28 mm round and two new weapons – the P90 as the sub-machine gun replacement, and the Five-Seven pistol, both chambered in the new cartridge. The other competitor for the NATO requirement was Heckler & Koch (HK) with their MP7 PDW and the new 4.6 × 30 mm round.

The next stage in the process saw NATO evaluate the new weapons and rounds in 2002–2003, though without result, as it proved to be impossible to reach a decision. As a result, the two companies looked to find a niche in the small arms marketplace. Since then, both the FN and HK solutions have been adopted by special forces, paramilitary units and law enforcement agencies around the world.

Consequently, the ‘official’ effort to replace the dominance of the 9 × 19 mm round essentially failed. The dominance of the 9 × 19 mm round was confirmed more recently, when in 2017, the SIG Sauer P320 won the US Army M17/M18 modular handgun system (MHS) programme. In 2022, both Australia and Canada announced the selection of new pistols, with the former selecting the SIG Sauer P320 XCarry Pro and the latter the SIG Sauer P320 – both weapons were selected in 9 × 19 mm. Clearly this round has stood the test of time and will remain in service for the foreseeable future.

Selecting the standard

As we have seen, the service life of small arms ammunition can be extremely long. We now turn to another small arms calibre that has stood the test of time and has also been a NATO standard since the 1950s, namely the 7.62 × 51 mm round. Post-1945, armies in Western Europe were equipped with a profusion of small arms in multiple calibres. For example, the US battle rifle round was 7.62 × 63 mm (.30-06), while the British used the 7.7 × 56R mm (.303), with all sorts of other battle rifle rounds lurking in the shadows. Amidst this confusion, there was also a growing realisation, based on combat experience, that new infantry weapons would be required to meet future requirements and that these would also need new ammunition types.

At the end of the 1930s, Belgian arms maker Dieudonné Saive at FN was working on the design of a new semi-automatic rifle for the Belgian Army when war intervened, forcing him into exile in England, where he continued working on the rifle design. In 1949 this resulted in the SAFN battle rifle in 7.92 × 57 mm Mauser, which was adopted by Belgium and exported to a number of different clients. One useful feature was that the design could accommodate different ammunition types depending on which weapon the client was operating.

The SAFN was a good weapon, but small arms requirements had moved on from a battle rifle of this nature and were headed to what we now would recognise as an assault rifle. Saive was aware of this and had prepared a design for a new weapon that eventually became the Fusil Automatique Léger (FAL). This would be a select-fire weapon and would use an intermediate round, which was initially the German 7.92 × 33 mm Kurz. Trials in the UK in 1947 led to further evolution in the weapon’s design when they switched to the British 7 × 43 mm (.280 British) intermediate cartridge, which was used in the British EM-2 future rifle design, selected as the British Army rifle in 1951. However, neither the round nor rifle entered service, in large part due to the US Army’s desire for a common cartridge used across NATO.

While Europe had been looking at intermediate rounds as a future solution, the US vision was a full-power round that was essentially better suited to a machine gun. While the new round offered extended ranges, it was too powerful to be utilised by the British EM-2, though the FAL could handle the new 7.62 × 51 mm round. So, while Britain, Belgium and others had been looking for an assault rifle using an intermediate round, they ended up adopting a battle rifle with a full-power round in line with US wishes.

The 7.62 × 51 mm round was officially adopted as NATO standard in 1954 and throughout the 1950s, various NATO nations took steps to introduce new weapons for the new round. The FN FAL would go on to become one of the most successful infantry weapons from the 1950s onwards, with production ending in the late 1980s. The vast majority of weapons were sold in 7.62 × 51 mm, with the single exception being Venezuela who ordered 5,000 rifles in 7 × 49 mm Liviano in 1954. This was an intermediate round developed specifically for Venezuela, but eventually the Venezuelan military decided that it made more sense to have all of their FALs in 7.62 × 51 mm and so the Liviano weapons were converted to the NATO round.

After imposing the 7.62 × 51 mm round on the rest of NATO, by the end of the 1950s, the US was having second thoughts, and this eventually led to the selection of the M16 assault rifle and the 5.56 × 45 mm M193 round. This then resulted in a NATO competition for a standardised round in that calibre, with the FN designed SS109 round selected as NATO standard in October 1980. The US opting for 5.56 × 45 mm was also a factor in influencing the Soviet decision to opt for a new small arms round in the 5.45 × 39 mm calibre and the AK-74 as the standard assault rifle, although the old 7.62 × 39 mm round still remains widely used.

New kids on the block

The longevity of standard military rounds is quite extraordinary, however, new rounds are being developed. For example, in 2007, US ammunition manufacturer Hornaday and Creedmoor Sports developed a new round for shooters looking for an improved round for long-range target shooting in the form of the 6.5 mm Creedmoor (6.5 CM). This round was developed for the commercial marketplace, but US Special Forces have adopted the 6.5 CM for their DMR and sniping applications preferring it to the 7.62 × 51 mm round. In Britain, the Royal Marines have selected the 6.5 CM for their new L129A2 DMR.

As to where the future of small arms ammunition is headed, this really depends on whether the US Army Next Generation Squad Weapon (NGSW) programme becomes a reality and starts to replace the US Army’s M4 carbine and M249 Squad Automatic Weapon (SAW). The programme was awarded to SIG Sauer in 2022 and a key component is the new round that SIG Sauer has developed for the programme – the 6.8 × 51 mm Common Cartridge (.277 SIG Fury). This new round is due to replace the current 5.56 × 45 mm round and the 7.62 × 51 mm round in certain roles, although the US military will also continue to use the older rounds.

Once the 6.8 × 51 mm round and its associated weapons become US Army standard, then the pressure to adopt the new round within NATO and by US allies will inevitably increase. This new US round is not the result of some technological revolution, but it can be considered an evolutionary development. Even so, it might yet change the path of small arms in both the US and internationally.

David Saw