The Colt AR-15 SP1 is a usa-made semi-automatic rifle chambered in 5.56x45mm NATO, introduced in 1964. Primary use: Range/Target. Type: Rifle Action: Semi-Automatic Caliber: 5.56x45mm NATO Capacity: 20 Year introduced: 1964, USA Weight: 86 oz Overall length: 39.5" Status: Discontinued Intended use: Range/Target