The Black Rain Bolt Carrier Group BRO-BCG for the M16/AR-15 is a nickel boron coated BCG.
NiB-X reduces friction to the absolute minimum and eliminates corrosion and abrasion. The slick finish also keeps carbon from adhering, so clean up is much faster and easier than with standard parts. Get an amazing BCG for your .223/5.56 rifle with the Black Rain BRO-BCG.