The M14 rifle is an American select-fire battle rifle designed in 1954. Using 7.62x51mm NATO ammunition, the M14 became the standard-issue rifle for the U.S military in 1959, replacing the M1 Garand for the U.S Army. It was the last American battle rifle issued in quantity to U.S military personnel, later being replaced by the M16 assault rifle.
The M14 is gas-operated, rotating bolt with a 22 inch (559 mm) barrel. After being replaced by the M16, the U.S Army converted several thousand M14s into M21 sniper rifles. It still remains in limited service and has been in service longer than any other U.S infantry rifle.