Bolt is made of Mil-spec Carpenter 158 steel Shot peened High pressure tested and Mag Particle Inspected. Gas key is machined out of bar stock chrome lined phosphate coated and secured with grade 8 fasteners and staked per mil-spec. Bolt carrier is phosphate outside and chrome lined inside. For packaging considerations BCG will be packed dry. As a result it will have a grey dusty appearance that will turn black with the application of CLP or other preferred lubricant.