WILSON COMBAT TR-BCA-SBN-556 BOLT CARRIER ASSEMBLY 5.56MM BLACK

The Wilson Combat Bolt Carrier Assembly in 5.56 NATO with black nitride finish (TR-BCA-SBN-556) is a mil-spec, full-auto profile bolt carrier group built from aerospace-grade materials with a salt bath nitride finish, designed for AR-15 builders, competitive shooters, and serious rifle owners who demand the same quality component Wilson Combat installs in their own factory-built rifles.

Key Features

• Manufacturer part number: TR-BCA-SBN-556
• UPC: 810025500757
• Caliber: 5.56 NATO, .223 Remington compatible
• Carrier profile: M16 full-auto profile
• Bolt material: Aerospace-grade 9310 tool steel
• Bolt finish: Salt bath black nitride, applied inside and out
• Carrier material: 8620 hardened steel
• Carrier finish: Salt bath black nitride
• Extractor material: 4140 gun-quality annealed cold drawn steel
• Gas key fasteners: Grade 8, properly staked
• Inspection: Magnetic Particle Inspected (MPI)
• Testing: High Pressure Tested (HPT), batch random
• Forward assist cuts: Yes, machined into carrier
• Ejector and extractor: Machined, mil-spec dimensions
• Weight: 14.4 ounces
• Compatible calibers: .223 Remington, 5.56 NATO, .300 Blackout, .204 Ruger, 300 HAM'R, 7.62x40 WT
• Platform: AR-15

Special Features

• The Wilson Combat Bolt Carrier Assembly (TR-BCA-SBN-556) uses aerospace-grade 9310 tool steel for the bolt, a material significantly tougher and more fatigue-resistant than the mil-spec minimum of Carpenter 158 steel, providing extended service life through high round counts without sacrificing flexibility or crack resistance
• The salt bath black nitride finish is applied to both the interior and exterior surfaces of the bolt and carrier, creating a surface treatment that penetrates into the steel rather than coating over it, meaning it will not peel, flake, or chip under heat cycles and extended use
• The M16 full-auto carrier profile adds mass compared to a standard semi-auto carrier, which slows the cyclic rate and improves reliability in carbine-length gas systems, short-barreled rifles, and suppressed configurations where gas pressure builds more aggressively
• The gas key is secured with Grade 8 fasteners and properly staked during final inspection at Wilson Combat, ensuring the key cannot back out under sustained firing and cause a gas leak that interrupts the cycling cycle
• Every bolt in this assembly is Magnetic Particle Inspected to detect sub-surface fractures and defects invisible to the naked eye, and batches are randomly High Pressure Tested to verify structural integrity before leaving the factory
• This is the same bolt carrier group Wilson Combat installs in their own production rifles, meaning buyers are getting a factory-qualified component rather than an aftermarket approximation

Practical Benefits

• AR-15 builders completing a custom or duty rifle will find the Wilson Combat Bolt Carrier Assembly (TR-BCA-SBN-556) drops into any quality mil-spec lower and upper without fitting, timing, or modification
• The black nitride finish significantly reduces the surface friction inside the carrier and bolt, allowing the assembly to run reliably with less lubrication than a phosphate or parkerized BCG requires, which is a real advantage in dusty, cold, or field conditions where applying oil is inconvenient
• The M16 carrier profile makes this assembly a strong choice for builders running pistol-length or carbine-length gas systems, suppressed setups, or .300 Blackout configurations where the additional carrier mass improves cycling consistency across a wide range of loads
• Competitive shooters, law enforcement, and duty-use AR owners who want a verified spare bolt carrier group will find this assembly ships ready to drop in and run without any break-in lapping or fitting
• The broad caliber compatibility covering .223 Remington, 5.56 NATO, .300 Blackout, .204 Ruger, 300 HAM'R, and 7.62x40 WT means a single TR-BCA-SBN-556 can serve as a spare across multiple AR-15 platform builds chambered in any of those cartridges
• The combination of MPI inspection, HPT batch testing, Grade 8 staked gas key, and aerospace bolt steel gives buyers documented confidence in the quality of each component rather than relying on a manufacturer claim alone

The Wilson Combat Bolt Carrier Assembly (TR-BCA-SBN-556) in 5.56 NATO is a proven platform for custom AR-15 builds, duty rifles, competition guns, and shooters looking for a factory-grade, fully inspected bolt carrier group that matches the standards of Wilson Combat complete firearms.