The primary service weapon of the UK’s Army, Navy and Air Force, the SA80 assault rifle was first fielded in the 1980s as a replacement for the L1A1 battle rifle. The rifle is a bullpup-configuration weapon, with the magazine and action positioned behind the trigger group. This allows for a more compact weapon system. Like the M4A1, the SA80A2 fires the 5.56-millimeter round and can accept the same magazine. Unlike the American carbine, the British one uses a short-stroke gas-piston system. In 2002, the weapons were upgraded to address a variety of shortcomings, including a modified bolt, extractor and hammer assembly, vastly increasing weapon reliability. In addition to the UK forces the SA80 has been sold to a number of Commonwealth countries, but overseas sales largely never materialized.