Short-stroke piston AR-15 with NiB-coated bolt carrier group and POF roller cam pin. Reduced fouling compared to standard DI. Type: Carbine Action: Semi-Automatic Caliber: 5.56x45mm NATO Capacity: 30 Year introduced: 2005, USA Weight: 118 oz Overall length: 32" Status: Active Intended use: Tactical, Law Enforcement, Sport Shooting