Nickel Boron M16 BCG with Anderson Logo laser engraved, made from 8620 steel, Bolt is made from 9310 steel. The 223 Bolt and Bolt Carrier Assembly comes complete with cam pin, firing pin and firing pin retainer. The 223 Bolt and Bolt Carrier Assembly comes complete with Cam Pin, Firing Pin and Firing Pin Retainer. This Bolt Carrier Group is engraved with the Anderson Manufacturing Logo.