Precision AR-15 pattern rifle in 6.5 Grendel — a cartridge Alexander Arms developed to extend AR-15 effective range beyond 800 yards. The Overwatch was the definitive factory 6.5 Grendel. Type: Rifle Action: Semi-Automatic Caliber: 6.5 Grendel Capacity: 26 Year introduced: 2011, USA Weight: 108.8 oz Overall length: 38.5" Status: Active Intended use: Precision, Hunting, Target