LaRue Tactical OBR (Optimized Battle Rifle) in 5.56 with 18-inch match-grade barrel. Built on LaRue precision machined receivers with PredatAR stock. Type: Semi-Auto Rifle Action: Semi-Automatic Caliber: 5.56x45mm Capacity: 30 Year introduced: 2008, USA Weight: 86 oz Overall length: 37.5" Status: Active Intended use: Precision/SPR