BCM® (MPI) complete bolt carrier group is fully assembled.
Bolt carrier group (auto version) for your AR15, M16, or M4. Parkerized exterior and chrome lined inside carrier. Machined to USGI specifications. This M16/M4 carrier includes the proper Mil-Spec gas key. Gas key is chrome lined and heat treated per GI specifications. Gas key is secured to carrier via USGI domestic mfg Grade 8 fasteners and properly staked per Mil-Specs. These properly hardened parts insure a strong staking and proper gas system functioning.
The bolt assembly is machined from the correct Mil-Spec Carpenter No. 158® steel, shot peened for increased strength, includes tool steel machined extractor and ejector, BCM Extractor Spring, and is HPT (High Pressure Tested) and MPI (Magnetic Partical Inspected).
Milspec Carpenter No. 158® steel
HPT Bolt (High Pressure Tested)
MPI Bolt (Magnetic Particle Inspected)
Shot Peened Bolt
Chrome Lined Carrier (AUTO)
Chrome Lined Gas Key
Gas Key Hardened to USGI Specifications
Grade 8 Hardened Fasteners
Key Staked Per Mil-Spec
Tool Steel Extractor
BCM Extractor Spring
Black Extractor Insert
Mil-Spec Crane O-Ring