MODERN MATERIEL Bolt Carrier Group (BCG)

.223/5.56 NATO AR15/M16 (full auto)

The main body of the carrier is crafted from 8620 Steel  – a low alloy nickel, chromium, molybdenum case hardened steel which offers high strength with excellent wear resistant properties.  It is the gold standard as well as the Mil-Spec for carrier construction.  After being manufactured, the carrier is sent out for that beautiful Black Nitride QPQ process that increases wear resistance and fatigue strength, provides additional corrosion resistance and improved lubricity.

The bolt is machined from 9310  – an industry standard for the production of aerospace components, automtive clutch parts and piston pins.  Again this part is finished with the Black Nitride QPQ process.  Each bolt is tested via MPI or magnetic particle inspection for defects.

The cam pin and extractor is made from 4140 steel while the gas key is 4130 and properly staked with grade 8 screws.