AR-15/M16/M4 5.56 Full Auto Bolt Carrier Group – NiB-X Black Nickel Boron

Bolt – Case hardened 9310, shot peened, magnetic particle inspected, with high-performance extractor, ejector springs, gas rings and special O-ring buffer.  NiB-X Black coated. Firing Pin – Manufactured, heat-treated, hardened, chromed and certified per government drawings. Carrier – AR-15 or M16 style (heavy weight), 8620 material, heat treated and case hardened. Manufacturing tolerances on inside diameters tightly controlled. NiB-X Black coated for durability and ease of cleaning. Gas Key – Hardened to USGI Specifications and attached using grade 8 hardened fasteners. NiB-X Black coated. Staked per military specifications. Cam pin – Manufactured, heat treated, hardened and certified per Government drawings. NiB-X Black coated.