Last reviewed: 2026-04-17 by Jake Terry, FFL07/SOT3 holder, 20+ years behind the counter.
The Dirty Bird D112 nickel boron bolt carrier group runs in any AR-15 chambered for 5.56 NATO, .223 Remington, or .300 Blackout. A bolt carrier group is the cycling engine of the AR platform — it strips the next round from the magazine, chambers it, locks into battery, absorbs recoil impulse through the buffer system, extracts the spent case, and ejects it through the port. This unit substitutes nickel boron for phosphate or nitride, lowering the coefficient of friction across all sliding surfaces and preventing carbon from bonding to the steel.
The Build
The carrier body is machined from 8620 tool steel and heat-treated to MIL-SPEC hardness. The bolt is cut from 9310 carpenter steel, shot-peened to close surface grain, and magnetic particle inspected for subsurface flaws. The gas key is forged to MIL-SPEC dimensions, attached with grade 8 fasteners, and properly staked — staking deforms the carrier body around the screw heads to prevent loosening under sustained fire. The extractor runs a MIL-SPEC coil spring, black insert, and Viton O-ring for consistent case extraction across a range of chamber pressures. Forward assist serrations are cut into the carrier, and the firing pin is shrouded to prevent out-of-battery discharge. The entire assembly — carrier, bolt, gas key interior — receives nickel boron treatment, which measures approximately 1-2 microns thick and self-lubricates under heat.
The Numbers
| Spec | Value |
|---|---|
| Platform | AR-15 |
| Cartridge Compatibility | .223/5.56 NATO/.300 BLK |
| Carrier Material | 8620 tool steel |
| Bolt Material | 9310 carpenter steel |
| Finish | Nickel boron (polished) |
| Gas Key | Forged MIL-SPEC, grade 8 hardware, staked |
| Bolt Treatment | Shot-peened, magnetic particle inspected |
| Extractor | Tool steel, MIL-SPEC spring, black insert, Viton O-ring |
| Weight | 11.84 oz |
| Manufacturer | Dirty Bird Industries |
| MPN | D112 |
| UPC | 00810084370063 |
All dimensions meet MIL-SPEC tolerances for correct function with standard AR-15 upper receivers, barrels, and buffer systems. The unit is 100% made in the USA and backed by Dirty Bird Industries’ lifetime warranty. For more AR-15 internal components, see our bolt carrier group section.
Safe Handling & Compliance
All firearms sold by Tatted Tacticals require transfer through a licensed Federal Firearms Licensee (FFL07) dealer. We ship to your designated FFL, where you complete ATF Form 4473 and a NICS background check before taking possession. Some states require additional state-level background checks, permits, or waiting periods — verify current requirements in your jurisdiction before ordering.
- Observe the four rules of firearms safety: treat every firearm as loaded, never point at anything you are not willing to destroy, keep your finger off the trigger until ready to fire, know your target and what is beyond it.
- Verify that your state and local jurisdiction permit ownership and possession of AR-15 pattern firearms and component parts before ordering.
- Installation requires disassembly of the upper receiver — ensure the firearm is unloaded, the magazine is removed, and the chamber is visually and physically inspected before beginning work.
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