Alexander Arms developed the .50 Beowulf cartridge and the AR-15-pattern semi-automatic rifle chambered for it. The .50 Beowulf fires a 300-400 grain bullet at 1,900-2,000 fps from a standard AR-15 lower with a modified bolt, barrel, and buffer. The upper receiver is compatible with a standard AR-15 lower. The cartridge is intended for brush hunting and vehicle stopping. Type: Rifle Action: Semi-Automatic Caliber: 50 Beowulf Capacity: 7 Year introduced: 2002, USA Weight: 152 oz Overall length: 36.5" Status: Active Intended use: hunting, tactical, sporting