Nickel Boron (NiB) is a durable bolt carrier group coating that provides reduced friction with excellent corrosion resistance. NiB impregnates the surface and becomes part of the metal. This process produces a surface harder than the metal itself. This characteristic provides overall wear properties superior to hard chromium. While NiB works as a lubricant additional dry film lubricate can be applied. The reduced friction reduces heat generated by metal-on-metal contact, so the gun runs cooler and parts last longer. Easy to clean, too—fouling brushes right off. This allowing for less time spent on cleaning and maintenance compared to the standard Mil-Spec bolt carrier group coating.