Fostech Complete Bolt Carrier Group Black

This is a standard full-auto M16 cut bolt carrier group. It is designed to function with the Echo AR-II and the Echo Sport.Bolt AssemblyBolt: Shot Peened; Magnetic Particle Inspected and MarkedBolt Material: 9310 Alloy SteelCompatibility: .223 / 5,56 / 300BLKExtractor: Shot Peened Hardened Tool SteelExtractor O-Ring: Viton, Mil-SpecGas Rings (3): Mil-SpecFinish: BLACK NITRIDEBolt CarrierMaterial: 8620 SteelDesign: Heavy Profile M16 Style(Preferred for most AR-15 Builds)Gas Key Screws: Grade 8; P