This high quality bolt carrier group is a valuable addition to your 6.5 Grendel/6mm ARC build.Features:M16-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