This 7.62A-39 Bolt Carrier Group (BCG) comes fully assembled and ready to drop into most mil-spec upper receivers chambered in 7.62A-39. All critical parts are coated with EXO Nickel Boron technology that provides permanent dry lubricity, extreme durability and increases both wear and corrosion resistance. EXO Nickel Boron makes for easy cleanup even with the corrosive 7.62A-39 ammo and will improve the performance of your rifle. The bolt keeps the Mil-Spec length for a more reliable bolt. The Extractor hardware includes a heavy spring, silicone insert, and o-ring to give better extraction tension. Included is a Black Rifle Arms Enhanced Firing Pin that has a longer length as well as other dimensional changes beyond overall length for better performance without over penetration. Due to the Mil-Spec bolt length and enhanced firing pin, you can shoot most Russian ammo including Tula.Note: Tula Ammunition and Golden Tiger have issues where some primers are set too far in and will still cause light strikes even with an Enhanced Firing Pin.Nickel Boron treated parts include:Bolt & Extractor (7.62A-39 compatible)M16 Cut Bolt CarrierCam PinCarrier Key