This AR-Stoner 300 AAC Blackout Barrel is an excellent choice for upgrading the AR platform with a more potent, versatile cartridge while maintaining one of the AR's key advantages: high ammunition capacity. The 300 AAC Blackout squeezes 30 caliber firepower into the traditional AR-15 envelope, and is available in either subsonic or supersonic ammunition varieties to serve a multitude of purposes. All that is needed to harness the enhanced performance of the 300 AAC Blackout is a simple barrel swap; the bolt, carrier, magazine and all other components remain the same as those used in a traditional 223 Rem/5.56 NATO rifle. These barrels features a heavy contour and 5/8"-24 threaded muzzle for easy installation of your preferred flash hider, muzzle brake and/or sound suppressor. Barrel extension and locator pin are both included and factory installed.