AR-556 MPR variant chambered in .450 Bushmaster with a 16.12-inch barrel, 15-inch M-LOK free-float handguard, and a 5-round magazine. Designed for hunters in straight-wall cartridge states requiring greater energy than .350 Legend can deliver. Type: Semi-Auto Rifle Action: Gas-Operated Caliber: .450 Bushmaster Capacity: 5 Year introduced: 2021, USA Weight: 7 oz Overall length: 36.5" Status: Active Intended use: Hunting