As an essential part of any rifle, the ODIN Works 6.5 Grendel, This USA made 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. **Also to note this BCG will work with 6MM ARC as well!!**