BCM Ar15 Bolt 5.56/223 Hp/mp Tested
BCM  (MPI)  Bolt AssemblyThe BCM bolt assembly is machined from the correct Milspec Carpenter No. 158 steel, shot peened for increased strength, includes tool steel machined extractor, BCM Extractor Spring, and is MPI (Magnetic Partical Inspected •Milspec Carpenter No. 158 Steel•HPT Bolt (High Pressure Test/ Proof)•MPI Bolt (Magnetic Particle Inspected)•Shot Peened Bolt•Tool Steel Extractor•BCM Extractor Spring•Black Extractor Insert•Mil-Spec O-Ring