The Wilson Combat bolt is precision machined from Carpenter No. 158 steel, shot peened for increased strength and a includes a tool steel extractor and ejector, appropriate extractor spring, and is MPI (Magnetic Particle Inspected) and randomly batch HPT (High Pressure Tested). The extractor is 4140 gun quality, annealed, cold drawn steel per the Mil-Spec. ompletely NP-3 plated, the semi-auto carrier includes the proper Mil-Spec gas key that is chrome lined and heat treated per GI specifications. It is secured to the carrier via Grade 8 fasteners and properly staked in Wilson's shop during final inspection. These precisely machined, finished and hardened parts will ensure long term proper gas system functioning and reliability.