LanTac M-Spec Features The Lantac M-Spec Bolt Carrier Group is precision machined to mil spec dimensions and tolerances in .223 Rem / 5.56 giving AR-15 owners a drop-in replacement that fits as the military spec intends. The carrier is full auto style with increased mass manufactured from 8620 steel that is case hardened and hard turned and ground so internal dimensions stay exact. Rather than the traditional Type M phosphate finish Lantac applies a nickel boron coating that improves corrosion resistance durability and lubricity across hard use. The bolt itself is machined from Carpenter 158 or 9310 steel shot peened and hard turned to the same military specification for consistent repeatable cycling. Each M-Spec BCG is fitted with a Lantac CP-R360 domed head cam pin precision machined from 17-4PH stainless steel hand polished and hardened to H900 condition to further reduce friction and wear inside the upper receiver. That attention to the small components is what separates an above mil spec build from a strictly to-spec part since reduced friction at the cam pin translates into smoother cycling over the life of the rifle. Finished in a silver nickel boron coating the BCG also offers easier cleaning thanks to its naturally lower-friction surface. AR-15 owners looking for a reliable corrosion-resistant bolt carrier group at a sensible price point will find the Lantac M-Spec a dependable upgrade over a basic phosphate carrier. LanTac M-Spec Specifications Manufacturer: LanTac Model: M-Spec Caliber: .223 Rem / 5.56 Compatible Hosts: AR-15 Material: Stainless Steel Color: Silver Finish: Nickel Boron Style: Full Auto Available At: GrabAGun