Dirty Bird AR-15 5.56/.223/300BLK Bolt Carrier Group - Phosphate/Crome-Lined

The Dirty Bird AR-15 Bolt Carrier Group comes fully assembled and ready to be dropped in. The carrier body is machined from 8620 steel, heat treated, & MP inspected. The carrier's bore is hard chromed for increased corrosion resistance and reliability, per mil-spec. The bolt is machined from Carpenter 158 tool steel, shot peened to relieve stress, individually high-pressure tested and MP inspected. The bolt and carrier are both treated with a Mil-Spec phosphate coating for its durability and corrosion resistance. This Dirty Bird Phosphate Bolt Carrier Group features a gas key tube that is hard chromed and properly torqued and staked screws.BoltMachined from Carpenter Technology No. 158 alloy.Heat treatedShot peened per ASTM B851/SAE AMS2430SIndividually High Pressure Tested (test fired)Individually Magnetic Particle InspectedManganese Phosphate FinishExtractorTool Steel ExtractorManganese Phosphate FinishMil-Spec O-RingCarrierMachined from AISI 8620 aircraft quality alloy per ASTM A108/A322-13Full Mass M16 ProfileStress RelievedHard Chrome BoreGas KeyMachined from 4130 chromoly steel alloy per ASTM A108/A322-13Grade 8 HardwareProperly StakedHard Chrome InternalPermatex sealedMADE IN THE USA!Backed by the Dirty Bird Industries Lifetime Warranty!