This bullpup rifle, years ahead of its time, really looked for a short time like it was going to become the new infantry rifle of the British Commonwealth. It was a very unconventional rifle for its time; not only was it a bullpup weapon reminiscent of the much-later L-85 series, it fired a small, short cartridge – the .280 British round, developed specifically for the purpose. The weapon incorporated a carrying handle and an optical sight to increase aiming accuracy. Experience with bullpup-type rifles at the time was small, and there were initially some difficulties with an overly-complicated operating mechanism in its predecessor, the EM-1. (The EM-1 borrowed heavily from another rather complicated design, the Nazi Gerät 06, a gas-operated roller-locking experimental rifle designed by Mauser.)
Enfield then turned to a less complicated (but still rather modern) gas-operated system with flap locking, and instead of the stamped steel of the EM-1, returned to largely machined parts, which were more suited to British manufacturing methods of the time. Another modern feature was that the primary sight was a 1x reflex-type sight which could be replaced with a compact 3.5x sight, with backup iron sights.
The Enfield EM-2 Bullpup Assault Rifle was ergonomically sound, well balanced with easy-to-reach controls and quite controllable in automatic fire. The Enfield EM-2 Assault rifle design worked quite well and was very reliable, and about the only thing that stopped its adoption by British armed forces was politics in this case, the beginning of NATO, the demand for a common NATO round for its members’ rifles, and an absolutely intractable United States, who insisted on what would become the 7.62mm NATO round. The British briefly considered going its own way rifle wise The EM-2 even received the British Army designation of “Rifle, Automatic, No. 9 Mk 1” and Belgium and Canada also produced experimental designs firing the .280 British cartridge. The US essentially bullied the rest of NATO into adopting the 7.62mm NATO cartridge.
Enfield tried converting the EM-2 Bullpup Assault Rifle to fire 7.62mm NATO, but the result was a rifle that (like most of the 7.62mm NATO rifles designed at the time) was uncontrollable in automatic fire. They then converted the EM-2 to fire only on semiautomatic, but the British Government, citing the costs and the length of the development program, decided to license a variant of the FN FAL (which became the L-1A1). Only 25 examples of the EM-2 were built in .280 British, plus the very few experimental 7.62mm NATO versions.
I feel this is a shame, as the British would have had an exceptional assault rifle at least a decade before anyone else in NATO; in addition, the .280 British is a much better intermediate round than the 5.56mm NATO that we eventually ended up with. (In addition, this would not be the last time that the US would use political bullying to stop the British from fielding a superior assault rifle) Just for the heck of it, I included a 7.62mm version below, though I don’t even know if any examples of those experimental versions of the EM-2 even exist anymore.