Rock River Arms LAR-15 Mid-Length A4 with 16-inch barrel and mid-length gas system. Flat-top upper, two-stage trigger standard. Type: Rifle Action: Semi-automatic Caliber: 5.56x45mm Capacity: 30 Year introduced: 2006, USA Weight: 64.5 oz Overall length: 34.5" Status: Active Intended use: Home Defense/Patrol