The M240, officially Machine Gun, 7.62mm, M240, is the US military designation for the FN MAG (Mitrailleuse à gaz, meaning Gas operated machine gun), a family of belt-fed, gas-operated medium machine guns firing the 7.62×51mm NATO cartridge.The M240 has been used by the United States Armed Forces since the late-1970s. It is used extensively by infantry, most often rifle companies; as well as ground vehicles; watercraft; and aircraft.