The Bushmaster XM-15 M4 Type is a civilian AR-15 built to M4 military configuration with a 14.5-inch barrel permanently pinned to achieve legal 16-inch minimum length, flat-top upper, M4 CAR stock, and M4 collapsible stock. The permanently pinned barrel extension was Bushmaster's civilian solution to the M4 military barrel length. Features chrome-lined barrel and M4 feed ramps. Type: Rifle Action: Semi-Automatic Caliber: 5.56 NATO Capacity: 30 Year introduced: 2003, USA Weight: 6.3 oz Overall length: 33" Status: Discontinued Intended use: Sport Shooting, Tactical