The Fail Zero EXO M16/M4 Bolt Carrier Group (brand part number FZ-M164-01-SAH) is a fully assembled bolt carrier group ready to drop into most mil-spec M16, M4, or AR15 upper receivers. Fail Zero coats every critical part in its EXO Nickel Boron finish, giving the assembly a permanently lubricious surface along with a meaningful boost to wear resistance and corrosion resistance over a standard phosphate BCG. That same coating sheds carbon and fouling easily, so cleanup between range trips takes a fraction of the time. It is a straightforward upgrade for anyone building or refreshing a mil-spec AR15.

Key Specifications

• Fits mil-spec M16, M4, and AR15 upper receivers for broad compatibility.
• Fully assembled bolt carrier group ready to install without additional parts.
• EXO Nickel Boron coating on all critical components.
• Permanent dry lubricity keeps the action running smoothly between cleanings.
• Increased wear and corrosion resistance compared to an uncoated BCG.

Frequently Asked Questions

What upper receivers does this bolt carrier group fit? Most mil-spec M16, M4, or AR15 upper receivers.

What does the EXO Nickel Boron finish add? Permanent dry lubricity plus increased wear and corrosion resistance, and faster cleanup.

Buy the Fail Zero EXO M16/M4 Bolt Carrier Group

Give your AR15 a smoother-cycling, easier-to-clean bolt carrier group. Order it from our Lubbock, Texas gun shop for fast, insured shipping, and browse more AR15 bolts for your next build.