Sons of Liberty Gun Works Bolt Carrier Group AR-15 223 Remington, 5.56x45mm, 300 AAC Blackout Hard Chrome

Sons of Liberty Gun Works Bolt Carrier Group is a premium BCG that leaves no stone unturned when it comes to quality control and performance.Bolt:Precision machined from Carpenter Technology No. 158 chrome-nickel alloyHeat treated per mil-spec,Shot peened per ASTM B851/SAE AMS2430S,Vibratory tumbledIndividual high pressure/proof (HP) testFull Auto test fired at assemblyIndividual magnetic particle inspection ASTM E1444/E1444M (MP)Markings deep laser engraved (SP=Shot Peened, HP=High Pressure Tested, MP=Magnetic Particle Inspection.)Extractor:Precision machined from 4340 tool steel alloy per SAE AMS6415T/AMS6484D (vs 4140)Heat treatedShot peen per ASTM B851/SAE AMS2430SExtractor Retaining Pin:Precision machined and ground S7 Tool SteelHeat treated per ASTM A681-08Shot peened per mil-spec printExtractor Spring:Tactical Springs/Sprinco 5 coil, ASTM Grade A401 Chrome Silicon wire stockHeat treatedStress relieved, Molybdenum-Disulfide infusedCryogenic processed (Hidden post winding)Mil-spec black insert/synthetic elastomer extractor buffer (nitrile-butadiene, shore hardness 80+/-5 durometer per MIL-PRF-6855)Ejector:S7 Tool SteelHeat treated per ASTM A681-08Shot peened per Mil-SpecEjector Spring:Heat treatedMil SpecGas Rings:Standard stainless steel per Mil-Spec X3Carrier:Machined from AISI 8620 aircraft quality alloy per ASTM A108/A322-13Full auto profileHeat-treatedCarburized/strain relieved, hard chrome borePrecision ground gas key interfaceSons of Liberty Battle Flag logo deep laser engravedGas Key:Machined from 4130 Chromoly steel alloy per ASTM A108/A322-13Heat-treated; hard chrome internalPermatex sealedGrade 8 hex screws torqued and staked Hidden per mil-specCam Pin:Precision machined 4340 Chromoly steel alloy per SAE AMS6415T/AMS6484DHeat-treated/processed per mil-specSolid film lubricant applied and cured per mil-specFiring Pin:Precision machined 8640 steel alloyHeat treated/processed per mil-specHard chrome plateFiring Pin Retaining Pin:Precision machined from 1038 carbon steelHeat-treated/processed per mil-spec