By late 1947 the British Army’s Armaments Design Department had designed three principal rifles for the Infantry Personal Weapon program. The new rifles got their official designations in January 1948.
They were Stanley Thorpe’s EM-1, the EM-2 designed by Capt. Kazimierz Stefan Januszewski and the EM-3, the latter the brainchild of Major J.E.M. Hall, an Australian.
The three designs shared one common design feature — they all featured the bullpup configuration, with the action behind the trigger. This layout produced a compact weapon ideally suited to close-quarters combat.
Hall began developing his rifle in 1944 as a response to problems he encountered during a small-arms course at the Royal Military College of Science at Shrivenham. He patented his bullpup design in February 1945.
Hall’s rifle was semi-automatic only and used an interesting vertically-sliding block to lock the rifle’s breech. He meant the weapon to fire a rimless .303-caliber round — although, in practice, the rifle was compatible with a range of cartridges. Hall’s EM-3 bullpup fed from a 10-round, detachable box magazine similar in dimensions to that of the Lee-Enfield’s.