The original 6.5 Grendel AR-15 pattern rifle. Alexander Arms developed the 6.5 Grendel cartridge specifically for extended-range AR-15 performance. Type: Rifle Action: Semi-Automatic Caliber: 6.5 Grendel Capacity: 26 Year introduced: 2004, USA Weight: 102.4 oz Overall length: 38.5" Status: Active Intended use: Hunting, Long Range