The General Dynamics XM312 is a .50 caliber, lightweight heavy machine gun. Developed by General Dynamics. Currently under development with a 100 box ammo box with a belt inside and the ammo box is attached to the gun. Also it was built to replace the M2 Browning Machine Gun because it is too heavy and too old so the US military totally need something to replace it, so the US military requested few companies and General Dynamics accepted the request and start developing it. In September 2005 the US military started firing the XM312.