The EM-2, also known as Rifle No9 Mk1 or "Janson rifle", was an experimental British assault rifle. It was designed to fire the experimental .280 British round that was being considered to replace the .303 British, re-arming the British and allied forces with their first assault rifles and new machine guns. The EM-2 never entered production due to the United States refusing to standardize on the .280 because they claimed it was "lacking power". However, the bullpup layout for a British service rifle was finally used some years later in the SA80 assault rifle. Only 59 were presumed to be built.