M1919A1 Medium Machine Gun Ammunition Belt (.30-06) but no metal tab The M1919 Browning is a .30 caliber medium machine gun that was widely used during the 20th century. It was used as a light infantry, coaxial, mounted, aircraft, and anti-aircraft machine gun by the U.S. and many other countries, especially during World War II, the Korean War, and the Vietnam War. In total there were six variants of the basic M1919 machine gun. The original M1919 featured a relatively heavy barrel, attempting to match the sustained fire capability of contemporary water-cooled machine guns.[citation needed] The M1919A1 featured a lighter barrel and a bipod. The M1919 originally fired the .30 cal M1906 (30-06) ball cartridge, and later the .30 caliber M2 ball cartridge, contained in a woven cloth belt, feeding from left to right. A metal M1 link was later adopted, forming a "disintegrating" belt.