The M2 Browning machine gun was first conceived in 1918, as a request by General John Pershing of the AEF for a large-caliber antiaircraft and antitank machine gun. John Browning scaled his M1917 water-cooled .30 caliber design up to .50 caliber, and the first prototypes were test fired in November of 1918. Impetus behind the project faltered after the Armistice, but Colt continued to develop the gun during the 1920s and 1930s. It was first adopted in 1922 by the US Coastal Artillery as an antiaircraft gun, but significant manufacture would not come until World War Two. By this time, the gun's main role had shifted, from antitank to being an aircraft armament, and some 2 million were made during World War Two, primarily as aircraft guns.

The M2 remains in service today, highlighting the brilliance and longevity of John Browning's designs.