| No. 9 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 | United Kingdom |
| Production history | |
| Designer | Stefan Kenneth Janson |
| Designed | 1948–1950 |
| Manufacturer | RSAF Enfield Chambons Birmingham Small Arms Company[1] |
| No. built | 59[2] |
| Variants | 6.25×43mm, 7×49mm, 7×51mm, 7.62×51mm NATO, .30-06 Springfield, Carbine, HBAR, Winter trigger variant[1] |
| Specifications | |
| Mass | 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, flapper-locked |
| 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, Mk.1 or Janson rifle, was a 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. It was an innovative weapon with the compact bullpup layout, built-in carrying handle and an optical sight.
The gun was designed to fire one of the first purpose-designed entirely new intermediate cartridges, designed to a 1945 requirement as a result of combat experience and German advances in weapons design during World War II. The round, the .280 British, was designed to replace the .303 round, which dated to the late 19th century. The EM-2 was intended to replace the Lee-Enfield bolt-action rifles and various submachineguns, while the TADEN would replace the Bren gun and Vickers machine gun.
As part of NATO standardization efforts, the United States claimed the .280 British round was too weak for use in rifles and machine guns, and instead favoured the much more powerful 7.62×51mm NATO round. A bullpup layout for a British service rifle was finally adopted some years later in form of the SA80 assault rifle, which remains in service today.