S&W's M&P15 variant chambered in .300 AAC Blackout with a 16-inch barrel. One of the early factory AR-15 offerings in the .300 BLK cartridge, designed to serve suppressor users and hunters seeking subsonic capability in an AR-15 platform. Type: Semi-Auto Rifle Action: Gas-Operated Caliber: .300 Blackout Capacity: 30 Year introduced: 2013, USA Weight: 6.6 oz Overall length: 35" Status: Active Intended use: Hunting, Suppressor Host, Range