EM-2 rifle

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 position was that the .280 British round was too weak for use in rifles and machine guns, insisting on standardisation on the existing and far more powerful 7.62×51mm NATO round. (Interchangeable with, but not identical to, the venerable .308 Winchester cartridge.) As the EM-2 could not be easily adapted to the longer and more powerful round, the design foundered.