The original AR-10, designed by Eugene Stoner and Armalite in 1956 — the direct ancestor of the M16. The modern Armalite AR-10 is a semi-auto .308 based on the original design. Lighter than contemporary .308 semi-autos at the time of its introduction. Type: Rifle Action: Semi-Automatic Caliber: 7.62 NATO Capacity: 20 Year introduced: 1956, USA Weight: 152 oz Overall length: 40.5" Status: Active Intended use: military, hunting, competition