The Bushmaster XM-15 QRC Piston is the gas-piston variant of the Quick Response Carbine, combining the value-oriented QRC pricing approach with a short-stroke piston operating system. Features a 16-inch barrel and standard M4 furniture. Offered as an alternative to the DI QRC for buyers who prioritized reduced fouling at a slightly higher price point. Type: Rifle Action: Semi-Automatic Caliber: 5.56 NATO Capacity: 30 Year introduced: 2011, USA Weight: 7 oz Overall length: 32.25" Status: Discontinued Intended use: Tactical, Sport Shooting