XM307 Advanced Crew Served Weapon

The XM307 Advanced Crew Served Weapon, also called the ACSW, was a prototype American automatic grenade launcher developed by General Dynamics Armament and Technical Products for the United States Army Tank-Automotive and Armaments Command. It grew out of the Small Arms Master Plan, which sought one modular crew-served weapon able to replace both the Browning M2 heavy machine gun and the Mk 19 40mm automatic grenade launcher. The XM307 fired 25x39mm impact or time-delayed grenades in high-explosive, high-explosive anti-tank and armor-piercing forms from a gas-operated, rotating-bolt action fed by a 31-round drum or a belt. It weighed about 22.7 kilograms, was 1,326 millimeters long, and used a retarded recoil system so that it could sit on a light tripod. The same design could be converted in minutes into the XM312 0.50 caliber heavy machine gun. Testing showed a rate of fire below what Army authorities would accept, and the program was cancelled in 2007, so the weapon never entered service.