JL Billet Bolt Carrier Group .308 Black Nitride Black JLB-308-BCG-BN. 56 MPI Bolt (Magnetic Particle Inspected) Carpenter 158 steel bolt (black nitride) Shot peened firing pin Grade 8 hardened fasteners 8620 heat treated carrier polished w/black...
JL Billet Bolt Carrier Group .308 Black Nitride Black JLB-308-BCG-BN. 56 MPI Bolt (Magnetic Particle Inspected) Carpenter 158 steel bolt (black nitride) Shot peened firing pin Grade 8 hardened fasteners 8620 heat treated carrier polished w/black...