This Aero Precision Bolt Carrier Group is a high quality BCG is a valuable addition to your 6.5 Grendel or 6mm ARC build. FeaturesM16-cut carrierMachined from 8620 steelType 2 Bolt Face (.136)Carrier has forward assist serrationsBlack Nitride Finish - advanced lower friction coating that minimizes the need for lubricants and cleaningProperly staked gas key6.5 Grendel bolt is machined from 9310 tool steelShot peenedHPT tested/MPI markedBlack o-ring insert on extractorHigh quality BCG