EM-2

No9 bullpup rifle
The EM-2 as Rifle No. 9
Type	Bullpup assault rifle
Place of origin	United Kingdom
Service history
In service	1951
Used by	See Users
Production history
Designer	Stefan Kenneth Janson
Designed	1948–1950
Manufacturer	RSAF Enfield Canadian Arsenals Limited Chambons Birmingham Small Arms Company
No. built	59
Variants	6.25×43mm, 7×49mm, 7×51mm, 7.62×51mm NATO, .30-06 Springfield, Carbine, HBAR, Winter trigger variant
Specifications
Weight	3.49 kg (7.7 lb)
Length	889 mm (35.0 in)
Barrel length	623 mm (24.5 in)
Cartridge	.280 British
Action	Gas-operated
Rate of fire	450–600 round/min (7.5 to 10 /s)
Muzzle velocity	771m/s (2,545 ft/s)
Effective firing range	700 m (770 yd)
Feed system	20-round detachable box magazine
Sights	Optical

The EM-2, also known as Rifle No.9 Mk1 or Janson rifle, was an experimental British assault rifle. It was briefly adopted by British forces in 1951, but the decision was overturned very shortly thereafter by Winston Churchill's incoming government in an effort to secure NATO standardisation of small arms and ammunition. An innovative weapon with the compact bullpup layout and an optical sight, it used one of the early intermediate cartridges (a concept introduced by the Germans with the 7.92×33mm Kurz) as a result of combat experience and German advances in weapons design during World War II.

It used the experimental, intermediate powered, but highly efficient .280 British round, which was designed to replace the venerable .303 round and Lee–Enfield rifle variants which had served since before the turn of the 20th century. The United States claimed the .280 British round was too weak for use in rifles and machine guns, and instead favored the much more powerful 7.62×51mm NATO round. As the EM-2 could not be easily adapted to the longer and more powerful round, it faded from use. However, the bullpup layout for a British service rifle was finally adopted some years later in form of the SA80 assault rifle, the EM-2's spiritual successor, which remains in service today.

In the immediate post–World War II era, the British Army, like many other forces, started research into their own assault rifle. The British Army had originally planned to replace their .303 inch rimmed cartridge before World War I, but were forced to keep it for another 30 years due to time and financial constraints.

With these constraints removed, they developed a new .280 inches (7.1 mm) intermediate-power round, and set about developing a new rifle to fire it, as well as considering a machine gun using the same round, the Taden gun.