The M56 Smart Gun is a fictional weapon, first appearing in Aliens, the second film in the Alien film series. It is significantly larger than the M41A Pulse Rifle and provides squad level supporting fire for USCM infantry units. The M56 fires 10x28mm caseless ammunition. In comparison, the M41A fires 10x24mm caseless ammunition. The M56 has a capacity of 300 rounds (or in rare cases, 500-round magazines). In comparison, the M41A has a maximum capacity of 99 rounds.