Short-stroke piston AR-15 with LWRC's proprietary self-regulating piston, Spiral Fluted barrel, and enhanced bolt carrier. One of the most specification-tested piston ARs in the market. Type: Rifle Action: Semi-Automatic Caliber: 5.56x45mm NATO Capacity: 30 Year introduced: 2013, USA Weight: 108.8 oz Overall length: 35.5" Status: Active Intended use: Tactical