Microbest Mil-Spec C158 HPT/MPI 5.56 Bolt Carrier Group Phosphate/Chrome-Lined

The Microbest BCG has been designed from the ground up with the most avid shooters in mind, using only the best materials available on the market today. The bolt assembly is machined from Carpenter No. 158(R) steel, shot-peened, MP marked, HP tested, and has a tool steel extractor that is machined from bar stock. Features: 4340 Extractor spring, mil-spec insert and extractor retainer pin in mag phosphate Mag phosphate ejector Mil-spec stainless gas rings 8620 carrier in FA profile chrome lined 4130 gas key with grade 8 retainers and sealed 4340 cam pin in mag phosphate 8740 firing pin in hard chrome 1038 retaining pin in mag phosphate