The WMD Guns AR-15 Full Auto Bolt Carrier Group features a nickel boron coating that imparts hardness, lubricity and protection against corrosion. This polished nickel BCG is treated with WMD Guns’ proprietary NiB-X® coating to give it a surface 40% harder than chrome and virtually impervious to fouling.

Every piece of this assembly is produced to military specifications and subjected to top-tier testing and metal treatment protocols to deliver a premium component that fits the AR-15, M16, and M4. The full auto design provides additional weight to support reliable cycling when used in a semi-automatic firearm.
Semi- and full-auto BCGs differ in the design of their back end, with the latter having extra material that enables a fully automatic trigger to function as intended. This rear lug adds a slight mass increase to the assembly.

Though the weightier back end is necessary to make a full-auto trigger work, it will not inhibit the function of a firearm built solely for semi-automatic operation. In fact, many shooters purposefully choose a full-auto BCG for their AR-15s because the extra mass helps with cycle timing, reduces wear and tear, and lowers recoil on lighter builds.

Specifications

• Bolt: Case-hardened 9310 steel with Mil-Spec NiB-X® extractor, gas rings and ejector, plus specialized O-ring buffer. Shot peened and magnetic particle inspected for quality assurance.
• Firing pin: Produced to government specifications, hardened, heat-treated and chromed.
• Carrier: 8620 material with full-auto design for function in M16s, M4s, and AR-15s. Produced, case-hardened, and coated under stringent quality control protocols.
• Gas key: Hardened per USGI specs and secured with grade 8 fasteners, Permatex Sealing Compound and military-recommended staking procedure.
• Cam pin: Manufactured and hardened per government drawings, then coated with NiB-X® for smooth function.

A full-auto M16 bolt group will not make an AR-15 fully automatic on its own — accomplishing that requires a few other parts, some paperwork, and a fat stack of cash. Buying a full-auto nickel BCG requires no special paperwork, and the NiB-X® coating is guaranteed for life.