Ruger AR-556 standard configuration in .450 Bushmaster with 16.38-inch barrel, Ruger's baseline AR-15 offering in the big-bore straight-walled hunting cartridge. Type: Rifle Action: Semi-Automatic Caliber: .450 Bushmaster Capacity: 4 Year introduced: 2019, USA Weight: 96 oz Overall length: 35.5" Status: Active Intended use: Hunting