The Black Rain Ordnance Complete Bolt Carrier is a high quality bolt carrier group built for the AR-308 platform. Precision machining, a properly staked gas key, and a standard mass carrier body ensure the reliability you'd expect from a premium BCG. The extremely slick Nickel Boron coating allows for easy cleaning and reduces the need for lubrication. Engraved with the B.R.O. biohazard logo, and intended for use with DPMS pattern barrel extensions.