This complete 7.62x39mm Bolt Carrier Assembly is Chrome Lined inside the Carrier for long wear and includes a staked-on Gas Key with Chrome Lining a complete Bolt Assembly Cam Pin Firing Pin and Firing Pin Retaining Pin. All components are of the highest quality and it has been magnetic particle inspected against internal flaws. The Bolt is machined from Carpenter 158 Steel. This Complete Bolt Carrier is guaranteed to fit and function in your Windham Weaponry 7.62x39mm rifle and many others – ready to insert in your Upper Receiver and take to the range. Note the 3 Rings machined into the bolt body to differentiate it from similar .223/5.56mm Bolts. YouÃÂll also note the larger bolt face that accommodates the 7.62 cartridge base.