Failzero M16/4 Full-Auto BCG Nickel-Boron w/ nickel-boron hammer

This pre-assembled Bolt Carrier Group (BCG) is compatible with most mil spec M16, M4 or AR15 upper receivers. It features critical components coated with EXO Nickel Boron technology that offers long-lasting dry lubrication, remarkable durability, and enhances both wear and corrosion resistance. With the patented Nickel Boron coating, your rifle’s performance can improve through reduced friction.