M1921 Browning machine gun

The M1921 Browning machine gun was a water-cooled .50-caliber (12.7 mm) machine gun designed by John Moses Browning. Development began in 1917 when Browning scaled up his .30-caliber M1917 to chamber a .50-caliber round, resulting in a prototype tested in 1918. The M1921 entered limited service with the United States Army and Navy in the late 1920s, and was succeeded by the M2 Browning in 1933.