M16 Rifle

The M16 is a family of American military assault rifles adapted from the ArmaLite AR-15 design for United States armed forces use, manufactured principally by Colt's Manufacturing Company and FN Herstal among other contractors, and it entered service in 1964 when the initial XM16E1 variant was issued to American troops. Chambered for the 5.56mm round, the rifle offered a lighter weight and higher rate of controllable automatic fire than the battle rifles it replaced, and it became the standard infantry weapon of the United States military during the Vietnam War. Approximately eight million M16-family rifles have been produced, making it the most-produced firearm of its caliber, and updated variants remain in front-line and reserve service today, giving it the distinction of the longest continuously serving rifle in United States military history. Its direct descendant, the shorter M4 carbine, has become the primary individual weapon of most American ground forces in the twenty-first century.