BOLT CARRIER COMPLETION KIT FOR AR-15/M16 Pair with your favorite AR-15 bolt or keep an extra set on hand just in case, this kit includes (1) mil-spec chrome-plated firing pin, chrome OR phosphate plated cam pin, and phosphate coated firing pin retaining pin. Includes Cam pin: 4140 steel, heat treated with hard chrome OR phosphate plating Firing pin: 8740 steel, precision ground, heat treated with hard chrome plating Firing pin retaining pin: mil-spec, phosphate coated Mfg: Kak Industry Llc.