The British Army had long considered the full power .30 calibre cartridges used by most European armies as being overpowered for that theatre of operations and on several occasions sought out alternatives. Whilst the full power .30 round had its place in colonial armies engaging numerically superior native forces at long ranges across wide expanses of the veldt or desert, an intermediate cartridge was better for engaging camouflaged, obscured and moving targets of opportunity. In 1913 the British Army was on the verge of adopting a .264″ cartridge and the P13 rifle but the outbreak of conflict in 1914 put an end to the idea: it was not a wise move to be changing weapons and all the supporting infra-structure for them whilst engaged in combat.

The concept of a lower powered cartridge, optimised for the the rapid engagement of fleeting targets at ranges out to 400 yards, resurfaced many times afterwards. In the 1940s, German designers introduced the 7.92 Kurz round and the Sturmgewehr 44 rifle, largely as a result of their experience of short range, urban conflict on the Russian front. The 7.92 Kurz (short) was an intermediate cartridge with reduced recoil and power but quite adequate against man sized targets at battle ranges. Combining the portability and high rate of fire of a sub-machine gun with the greater accuracy of a rifle, the  Stg 44 / 7.92 kurz combination marked a turning point in military weapons design. It entered service too late, and in numbers too small to change the outcome of WW2 but it did have a very significant influence over the development of future military firearms.

Above: Partially disassembled Sturmgewehr 44 

In post-war Russia, Mikhail Kalashnikov designed the AK-47 assault rifle based around an intermediate cartridge, the 7.62x39mm. Debate rages to this day how much of this rifle was original and if elements of its design were borrowed from the Stg 44 and even the Mondragon, but it must rank as perhaps the most widely used and significant firearm of the 20th century.

NATO too was conducting trials with a view to standardising on a new cartridge. In Britain, design teams at the Royal Small Arms Factory, Enfield, put forward a number of concepts and from these emerged the basis of the Rifle, Experimental Model 2 or EM-2. A bullpup design, allowing a long barrel to be packaged in a short overall length, the rifle was chambered for a .280″ cartridge.

Above, EM-2 alongside a Stg-44

Trials showed the rifle to be an excellent weapon: accurate, powerful enough, reliable and easy to become proficient with. Its short length allowed it to be a potent weapon in the close operations typical of street fighting, and easily manoeuvred in and out of the close confines of armoured personnel carriers. It introduced into the British Army the concept of optical sights as a standard fitment, and would have replaced both the existing rifles and sub-machine gun to become the first universal infantry weapon for all-arms service. Multi-national service trials showed both the rifle and its ammunition to be the best combination of its era.

 Above: Rifle, No 9, Mk1.

The EM-2 was adopted as the British Army’s new rifle on April 25, 1951 as the Rifle, Automatic, Calibre .280, Number 9. Many other nations also expressed an interest n adopting the rifle and the .280 cartridge which had performed extremely well in NATO trials. Unfortunately, its service was short lived. The US dismissed the concept of intermediate cartridges and insisted on NATO adopting a full power .30 cartridge as its standard round. In 1954, under intense US pressure, NATO adopted the US based 7.62x51mm cartridge as its standard infantry calibre and the Rifle No 9 was replaced in British service by the FN FAL.

Interestingly, in Russia, a German designer, Koborov, similarly saw and appreciated the advantages a bull-pup rifle firing an intermediate power cartridge would have in modern mechanised manoeuvre warfare. He submitted a design, the TKB-408,  based on a tilting bolt, bullpup action to the Red Army in 1946. Capable of semi- or full automatic firing, it had a length of 790mm and was optimised for mass production. It lost out to the AK-47.

Above. TKB-408 7.62×39

Ultimately, history was to vindicate the British approach. In the 1960s, the USA found the 7.62mm round too powerful for modern warfare and introduced a 5.56mm round and the AR series of rifles to employ it. These, in turn, proved not powerful enough and current trials to find a replacement are centred on 6.8mm intermediate cartridges as this appears to provide the best balance of power, range, accuracy and terminal ballistics.  The British may take some comfort in noting of course that 6.8mm just happens to be the metricised equivalent of the old 1913 .264″ cartridge.