As an essential part of any rifle, the ODIN Works .223 Black Nitrided, Type 2 bolt face is Mil-Spec and comes with a Case Hardened 8620 Steel Black Nitride Finish. This advanced low friction coating minimizes the need for lubricants. 4130 Steel Gas Key attached with Grade 8 hardware and properly staked into a milled "valley" to ensure proper positioning. Don't skimp on an essential part of your build, go with only the best. FeaturesMil-Spec dimensionsBolt Carrier Group Material: Case Hardened 8620Low friction coating minimizes the need for lubricantsGas Key: 4130 Steel attached with Grade 8 hardware and properly staked into a milled "valley" to ensure proper positioningCam Pin: Hardened 4340 cam pinFiring Pin: Mil Spec firing pin made of 8740 steel, center-less ground and Hard Chrome coatedBolt Assembly: The Bolt is "true" Mil Spec dimension and external surfaces are CNC ground after heat treat for a precision fitBolt Material: Case Hardened 9310 ...