LaRue OBR in 7.62 NATO with 18-inch barrel. Piston-driven AR-10-pattern precision battle rifle. Type: Rifle Action: Semi-Automatic Caliber: 7.62x51mm NATO Capacity: 20 Year introduced: 2009, USA Weight: 9.8 oz Overall length: 38" Status: Active Intended use: Precision, Designated Marksman