The One Horse M16 Nickel Boron Bolt Carrier Group (part no. OH-UBC02) is rated for both 5.56 NATO and .300 Blackout, since both cartridges share the same bolt face and headspace. One Horse finishes this carrier in nickel boron, a low-friction coating that shooters favor for smoother cycling and easier field cleaning than a standard phosphate finish.

Key Specifications

• Finished in nickel boron, a low-friction coating that resists carbon buildup and wipes clean faster than phosphate.
• Machined to the M16 carrier profile, the heavier full-auto-cut carrier commonly chosen for its added reciprocating mass.
• Rated for both 5.56 NATO and .300 Blackout, since the two cartridges share bolt face and headspace dimensions.
• Ships at approximately 0.8 lb, in line with a complete M16-profile bolt carrier group.

Frequently Asked Questions

Will this work in both 5.56 and .300 Blackout uppers? Yes, both cartridges share the same bolt face and headspace, so one BCG covers either chambering.

What does the M16 carrier profile mean? It’s the heavier, full-auto-cut carrier shape; it runs fine in a standard semi-auto AR15 and is a common reliability upgrade.

Buy the One Horse M16 Nickel Boron Bolt Carrier Group

Order this nickel boron BCG from One Horse. Order from a Lubbock, TX gun shop. Browse our full AR bolt carrier groups selection for more builds.