We are extremely pleased to finally be able to offer a chrome bolt carrier group manufactured by Toolcraft! These BCGs exceeded our expectations.The combination of state-of-the-art coating technology and improved coating materials makes these some of the finest chrome bolt carrier groups ever manufactured.The Physical Vapor Deposition (PVD) process is used to apply a very thin (~3 micron) layer of Chromium Nitride (CrN) to all parts. The result is a BCG with the classic look of traditional chrome but with significantly increased performance.Chromium Nitride (CrN) benefits Twice as hard as traditional hard chrome Uniform thickness, no buildup in corners Adhesion is superior to traditional chrome plating Low coefficient of frictionThese chrome BCGs feature Mil-Spec Carpenter 158 bolts, M-16 full-auto profile carriers and the famous Toolcraft lifetime warranty.BoltShot Peened; MPIBolt MaterialCarpenter 158 SteelBolt FinishChromium Nitride (CrN), PolishedCaliber223 | 5.56 NATO | 300 BlackoutExtractor O-ringViton; Mil SpecCarrier Material8620 Steel, Toolcraft ProprietaryCarrier FinishChromium Nitride (CrN), PolishedCarrier DesignM16 Full Auto StyleGas Key Material4130 SteelCam Pin Material4140 SteelCam Pin FinishChromium Nitride (CrN), PolishedExtractor MaterialTool SteelFiring Pin Material8740 Steel; Hard Chrome PlatedManufacturerToolcraft