CMC Enhanced Bolt Carrier Group - AR-15 5.56/223/300 Blackout

Hard use is the whole point here. This AR-15 bolt carrier group is built around a case-hardened 8620 steel carrier with a flared rear profile that shifts bearing surfaces to help reduce carrier tilt and cant during recoil. CMC also gives the carrier fewer contact points to cut friction, while the added mass helps maintain gas pressure and dwell time for better extraction, especially on suppressed rifles and short-barreled setups.

The bolt itself stays true to mil-spec dimensions and is CNC ground after heat treatment for a precise fit. CMC machines the area behind the gas rings where carbon tends to build up, which makes cleanup less of a chore and supports long service life. Bolt components are made from 9310 case-hardened steel, shot peened, and finished in black nitride.

Supporting parts follow the same practical approach: a hardened 4340 cam pin, mil-spec 8740 steel firing pin, and a mil-spec extractor spring with O-ring. It is compatible with .223 Remington, 5.56 NATO, and .300 Blackout AR-15 platforms, and it is MPI and HPT tested.

Specifications

• Fits AR-15 platforms in .223 Remington, 5.56 NATO, and .300 Blackout
• Carrier material: case-hardened 8620 steel
• Bolt material: 9310 case-hardened steel
• Finish: Black Nitride
• Hardened 4340 cam pin
• Mil-spec 8740 steel firing pin
• Mil-spec extractor spring with O-ring
• MPI and HPT tested
• Enlarged forward ports
• Optimized for suppressor use
• MPN: 81631
• UPC: 810943030961