The Wilson Combat Bolt Carrier Assembly in 5.56 NATO with a black nitride finish (brand part no. TR-BCA-SBN-556) is a mil-spec AR-15/M16 bolt carrier group built for rugged, dependable operation. The bolt is precision machined from aerospace-grade 9310 tool steel, and the hardened 8620 steel carrier has forward assist cuts. The gas key is properly staked, and the ejector and extractor are machined for consistent case handling. Wilson Combat uses this same assembly in its own fully built rifles, so it suits a duty carbine, a range rifle or a rebuild that needs a proven carrier.

Key Specifications

• The assembly is built for 5.56x45mm NATO AR-15 rifles, the cartridge Wilson Combat lists for this carrier.
• The finish is black nitride, a coating Wilson Combat applies for robust dependability.
• The bolt is aerospace-grade 9310 tool steel, chosen for toughness.
• The carrier is hardened 8620 steel, a durable base for the nitride finish.
• The carrier has forward assist cuts, so it works in uppers with a forward assist.
• The gas key is properly staked, so it stays secure through long-term use.
• The ejector and extractor are machined for consistent case handling.
• This is the auto (full-auto profile) carrier, slightly heavier than a semi-auto carrier, which Wilson Combat says can benefit carbine-length and shorter gas systems and short-barreled or suppressed rifles.
• It is built to Mil-Spec dimensions for the AR-15/M16 pattern.
• It is a drop-in fit for any quality 5.56 case-head-based AR rifle, including .223/5.56 NATO, .300 Blackout, .204 Ruger, 300 HAM’R and 7.62×40 WT.

Frequently Asked Questions

What is the difference between the auto and semi-auto carrier? Wilson Combat says the two differ only in carrier weight and external profile. The auto carrier is slightly heavier, adding mass that lowers cyclic rate on carbine-length and shorter gas systems, while the semi-auto carrier is lighter for rifle-length gas systems.

What is the carrier and bolt made of? The bolt is aerospace-grade 9310 tool steel and the carrier is hardened 8620 steel, finished in black nitride.

Which rifles will it work in? Wilson Combat lists a drop-in fit for any quality 5.56 case-head-based AR rifle, including .223/5.56 NATO, .300 Blackout, .204 Ruger, 300 HAM’R and 7.62×40 WT.

Buy the Wilson Combat AR-15 Bolt Carrier Assembly, 5.56 NATO, Black Nitride

A nitride-finished carrier is a durable upgrade for a 5.56 AR-15 upper. Order it from our Lubbock, Texas gun shop for fast, direct shipping, and browse more AR bolt carrier groups to complete your build.