CMC Triggers Enhanced Bolt Carrier Group was designed for shooters who demand superior performance weapon components in the heart of their firearm. Carrier Assembly: The flared rear of the enhanced bolt carrier is designed to reduce carrier tilt/cant during recoil and increase reliability by strategically relocating key bearing surfaces. Made from Case-hardened 8620 steel.The CMC enhanced carrier has fewer points of contact, resulting in less friction area. The increase in mass ensures proper gas pressure and increases dwell time, thus improving extraction while shooting suppressed or short-barreled rifles (SBRs). Bolt Assembly: The Bolt is a "true" Mil-spec dimension. The external surfaces are CNC ground after heat treatment for a precision fit. The bolts are held to the highest possible tolerances. The "trumpet" area behind the gas rings, where carbon collects, is precision CNC Ground after heat treatment, to ensure as smooth of an area as possible, easing clean up and longevity. Made from 9310 Case Hardened Steel, bolt components are Shot Peened & Black Nitride coated.Black Nitride finishEnlarged forward portsOptimized for suppressor useHardened 4340 cam pinMil-Spec 8740 steel firing pinMPI and HPT testedMil-Spec Extractor Spring & O-Ring.223/5.56/300BLK compatible