Mitchell Defense Enhanced M16 6mm ARC Bolt Carrier Group 9310 Bolt Black. It features a nitride-treated 9310 MPI-inspected bolt for strength paired with a full-mass 8620 M16 carrier for consistent cycling. The billet extractor with O-ring improves case control while SP4-coated gas rings reduce friction and increase wear resistance. The gas key is properly torqued and OCKS-staked for maximum retention. Clean-running durable and optimized for ARC's specific performance requirements this BCG ensures reliability across a wide range of barrel and gas system lengths. Specifications for Mitchell Defense Enhanced M16 6mm ARC Bolt Carrier Group: Manufacturer: Mitchell Defense Color: Black Finish: Nitride Caliber: 6mm ARC Gun Make: AR Platform Gun Model: AR-15 Features of Mitchell Defense Enhanced M16 6mm ARC Bolt Carrier Group Nitride-treated 9310 bolt optimized for 6mm ARC pressure curves Full-mass 8620 M16 carrier for consistent cycling Billet extractor with O-ring for stable extraction SP4-coated gas rings for reduced friction and extended durability OCKS-staked gas key for secure retention Chrome-plated firing pin for enhanced longevity Engineered for smooth operation across varied ARC barrel and gas system lengths Package Contents: Mitchell Defense Enhanced M16 6mm ARC Bolt Carrier Group What firearm models does the manufacturer say Mitchell Defense Enhanced M16 6mm ARC Bolt Carrier Group is compatible with? The manufacturer says that Mitchell Defense Enhanced M16 6mm ARC Bolt Carrier Group is compatible with AR-15Mitchell Defense 612001: Enhanced M16 6mm ARC Bolt Carrier Group 9310 Bolt Black