Smith & Wesson M&P15 AR-15 platform chambered in .450 Bushmaster with 16-inch barrel, one of the first production AR rifles in this big-bore straight-walled cartridge. Type: Rifle Action: Semi-Automatic Caliber: .450 Bushmaster Capacity: 5 Year introduced: 2019, USA Weight: 96 oz Overall length: 32" Status: Active Intended use: Hunting, Sporting