Nickel-boron-coated AR-15 bolt carrier group for .223 Remington, 5.56 NATO, and 300 Blackout uppers. The NiB coating is dramatically slicker than phosphate or nitride finishes — the surface almost self-lubricates, carbon wipes off with a dry patch, and blowback residue clears faster than either black nitride or standard mil-spec parkerized bolts. A drop-in replacement for any standard mil-spec upper receiver.
Bolt features
- Carpenter 158 steel — the mil-spec bolt material
- Heat-treated and shot-peened for fatigue resistance
- MPI (magnetic particle) tested to detect any surface or subsurface flaws
- Nickel boron coating on the bolt body and extractor for corrosion resistance
- Relief-cut cam pin channel to reduce bolt-lug stress
Carrier features
- 8620 tool steel
- Nickel boron coating inside and out — including the gas key bore
- Full-auto M-16 profile (full mass) — runs semi- and full-auto lowers
- Properly staked gas key screws (Grade-8, torqued and staked to spec)
Fit
- AR-15 uppers in .223 Rem, 5.56 NATO, or 300 AAC Blackout
- Standard mil-spec upper receivers (Colt-pattern, forged 7075-T6 or billet)
- Not for LR-308, AR-10, or .308 platforms — those need a large-frame BCG
Recommended lube for NiB carriers: a light film only. NiB does not need heavy oiling to run — over-oiling collects carbon rather than sheds it. Wipe down between range trips with a dry patch; a full detail-strip clean is rarely needed inside the first 5,000 rounds.
