.50 BMG Browning M2 Machine Gun by Colt. The Browning M2 is an automatic machine gun chambered in .50 BMG. It is air-cooled, belt-fed, short recoil-operated, and is capable of firing up to 850 rounds per minute. It was designed to be used as an anti-personnel, anti-tank, and anti-aircraft weapon. Manufactured by Colt Hartford Connecticut USA, Colt's production of M2 Heavy Barrels (M2HB) was 18,429 from 1940 to 1943, out of a total of 240,702 .50 BMG calibers. Updated and reconditioned to new in April 1945 at the Raritan arsenal in New Jersey, see markings RA on main plate and 4 45 (numbers struck for April 1945) on inside of breech housing cover.