Basic infantry rifle using ArmaLite developed .223 caliber ammunition. The AR-15 was licensed to the Colt’s Patent Firearms Manufacturing Company in January 1959.

The U.S. Air Force completed tests of the AR-15 in January 1961. The Air Force procured 8,500 rifles in 1961 and standardized the AR-15 in 1963. 85,000 rifles were purchased in that year. The military designation of the AR-15 is M-16.

The Army also ordered 85,000 rifles in 1963. An additional 35,000 were ordered in 1964, 100,000 in 1965, and 100,000 in 1966. These rifles were initially issued primarily to combat troops in the Dominican Republic and to Special Forces, Airborne, helicopter crews, Air Commando and other special category troops in Vietnam. The M-16 was type classified standard A in 1965 and became the military’s basic service rifle.