Seeing "MIL-SPEC" as just the starting point, Faxon set out to ensure the best options are available for their demanding customers. Improvements include using 9310 tool steel for the bolt, nitriding the assembly to increase surface hardness, decrease resistance, and have superior corrosion resistance compared to typical chrome and phosphasted bolt carrier groups. All bolts are fully MPI tested to ensure the material is sound and without defects. Bolt lugs are chamfered 45 degrees to ensure reliable action for even the highest pressure hand loads and fast lightweight actions. Faxon Bolt Carrier Groups are Superfinished to reduce friction, increase smoothness of operation, and reduce fouling. Gas keys use grade 8 fasteners and are fully staked for a lifetime of service. DPMS Gen 1 Compatible Bolt: 9310 Tool Steel Construction (Stronger than C158)Full MIL-SPEC Heat TreatmentShot Peened to MIL-SPECBack of Lugs Chamfered for ReliabilityNested .308 Spec Springs with O-RingQPQ - Salt Bath Nitrided Extractor: 4140 Tool Steel ConstructionFully Heat TreatedShot Peened Per MIL-SPECQPQ - Salt Bath Nitrided Carrier & Key: Superfinished CarrierCarrier: MIL-SPEC 8620 Steel MaterialKey: 4140 Steel MaterialFully Heat TreatedForward Assist SerrationsGrade 8 FastenersFully & Properly Staked KeyQPQ - Salt Bath Nitrided Cam Pin: 4140 Pre-Hardened Steel MaterialQPQ - Salt Bath Nitrided#html-body [data-pb-style="62DF828D13091"]{justify-content: flex-start; display: flex; flex-direction: column; background-position: left top; background-size: cover; background-repeat: no-repeat; background-attachment: scroll; border-style: none; border-width: 1px; border-radius: 0px; margin: 0px 0px 10px; padding: 10px;}#html-body [data-pb-style="62DF828D1309F"]{border-style: none; border-width: 1px; border-radius: 0px; margin: 0px; padding: 0px;}