“Nickel Boron (NiB-X®) bolt carrier groups aren’t new, but they are always a shade of grey or silver… until now. WMDguns.com has figured how to add a special top layer that gives a black color to NiB-X coated parts. Gear Report was sent the very first WMD Guns Black NiB-X AR15 Bolt Carrier Group for testing and review. In the video below Josejuan walks us through the details of the Black NiB-X Coated BCG and we see it being shot in a .300 Blackout AR15…”