The M242 Bushmaster chain gun is a 25 mm (25×137mm) single-barrel chain-driven autocannon. It is used extensively by the U.S. military, such as in the Bradley fighting vehicle, as well as by other NATO members and some other nations in ground combat vehicles and various watercraft. Hughes Helicopters in Culver City, California was the original designer and manufacturer. McDonnell Douglas Helicopters acquired Hughes Helicopters in 1985, and merged into Boeing Corporation in 1997. In 2002, it was sold again to Alliant Techsystems, which merged with Orbital Sciences Corporation in 2015 to form Orbital Science ATK and was, in turn, bought out by Northrop Grumman in 2018. As of 2019, Northrop Grumman Innovation Systems produces the gun.