The .280 British was an experimental rimless bottlenecked intermediate rifle cartridge. It was later designated 7 mm MK1Z, and has also been known as 7 mm NATO, .280/30, .280 Enfield, .280 NATO, 7 mm FN Short, and 7×43mm. It was designed by the British Army in the late 1940s, with subsequent help from Fabrique Nationale in Belgium and the Canadian Army. The .280 British was tested in a variety of rifles and machine guns including the EM-2, Lee-Enfield, FN FAL, Bren, M1 Garand and Taden gun. Despite its success as an intermediate cartridge, the .280 British was not considered powerful enough by the U.S. Army and several variants of the .280 British were created in an attempt to appease the U.S. Army. However, the U.S. Army continued to reject these variants, ultimately adopting the 7.62×51m