Brownells194199657
Brownells Ar-15 5.56Mm Bolt Carrier Group, Nitride$105.23
Availability: In Stock
The Rosco Manufacturing AR-15 Bolt Carrier Group in phosphate finish is a no-nonsense, combat-tested component built for shooters who demand reliability under hard use. Whether you're running a 5.56 NATO rifle for hunting, competition, or training, this phosphate-coated BCG delivers the durability and consistency you need without the premium price tag of specialty coatings. Rosco engineered this group to MIL specification, properly staked with a chrome-lined gas key and carrier, and rated for full-auto fire — which means it'll handle anything you throw at it on semi-automatic without breaking a sweat.
The bolt is shot-peened, mag-particle tested (MPI), and high-pressure tested (HPT) to ensure it locks up tight and true with your barrel extension. Rosco matches the bolt to each carrier for consistency, and includes their upgraded Sprinco extractor kit to guarantee smooth, reliable extraction cycle after cycle. The phosphate coating is a proven, time-tested finish that resists corrosion while offering a slightly rougher surface — useful if you prefer a traditional mil-spec look and feel. Every critical component, from the 8620 steel carrier to the 4340 hardened cam pin and heat-treated 8740 firing pin, is built to specification and pressure-tested at the factory.
This is a BCG designed by listening to what actual shooters and military users need, not what looks flashiest on a shelf. If you're building or rebuilding an AR and want a reliable, properly-staked carrier group that won't let you down, the Rosco phosphate BCG is a solid, affordable choice.
| Caliber | 5.56 NATO / 300 BLK |
| Finish | Phosphate with Chrome-Lined Gas Key and Bolt Channel |
| Carrier Material | 8620 Steel |
| Gas Key Material | 4130 Steel, Grade 8 hardware, properly staked |
| Cam Pin | Hardened 4340 Steel |
| Firing Pin | 8740 Steel, Heat Treated, MIL-Spec, Hard Chrome Plated |
| Bolt Material | C158 Steel, Phosphate Coated, MPI/HPT Tested |
| Extractor | 4140 Steel, Heat Treated, Shot Peened (Upgraded Sprinco Kit Included) |
| Ejector | S2-S7 Tool Steel, Shot Peened |
| Rating | Full-Auto Rated |
| Standard | MIL Specification |
Yes. This Rosco BCG is chambered for 5.56 NATO and is compatible with any standard 5.56 upper receiver. It's also compatible with 300 BLK uppers if you run that caliber.
Yes. The Rosco phosphate BCG is engineered and tested to handle full-auto fire rates, so it's built robust enough for whatever semi-automatic use you'll put it through.
The BCG ships with an upgraded Sprinco extractor kit, giving you a complete, ready-to-install bolt carrier group. No additional components are needed for a standard build.
Phosphate is a traditional, mil-spec finish that resists corrosion and provides a classic appearance. Rosco also offers a nitride-coated version if you prefer that coating; check specs on the nitride model for material differences.
SKU: 167516333 • Width: 1.25in • Height: 1.25in • Depth: 8in • Weight: 1oz
Availability: In Stock
The Rosco Manufacturing AR-15 Bolt Carrier Group in phosphate finish is a no-nonsense, combat-tested component built for shooters who demand reliability under hard use. Whether you're running a 5.56 NATO rifle for hunting, competition, or training, this phosphate-coated BCG delivers the durability and consistency you need without the premium price tag of specialty coatings. Rosco engineered this group to MIL specification, properly staked with a chrome-lined gas key and carrier, and rated for full-auto fire — which means it'll handle anything you throw at it on semi-automatic without breaking a sweat.
The bolt is shot-peened, mag-particle tested (MPI), and high-pressure tested (HPT) to ensure it locks up tight and true with your barrel extension. Rosco matches the bolt to each carrier for consistency, and includes their upgraded Sprinco extractor kit to guarantee smooth, reliable extraction cycle after cycle. The phosphate coating is a proven, time-tested finish that resists corrosion while offering a slightly rougher surface — useful if you prefer a traditional mil-spec look and feel. Every critical component, from the 8620 steel carrier to the 4340 hardened cam pin and heat-treated 8740 firing pin, is built to specification and pressure-tested at the factory.
This is a BCG designed by listening to what actual shooters and military users need, not what looks flashiest on a shelf. If you're building or rebuilding an AR and want a reliable, properly-staked carrier group that won't let you down, the Rosco phosphate BCG is a solid, affordable choice.
| Caliber | 5.56 NATO / 300 BLK |
| Finish | Phosphate with Chrome-Lined Gas Key and Bolt Channel |
| Carrier Material | 8620 Steel |
| Gas Key Material | 4130 Steel, Grade 8 hardware, properly staked |
| Cam Pin | Hardened 4340 Steel |
| Firing Pin | 8740 Steel, Heat Treated, MIL-Spec, Hard Chrome Plated |
| Bolt Material | C158 Steel, Phosphate Coated, MPI/HPT Tested |
| Extractor | 4140 Steel, Heat Treated, Shot Peened (Upgraded Sprinco Kit Included) |
| Ejector | S2-S7 Tool Steel, Shot Peened |
| Rating | Full-Auto Rated |
| Standard | MIL Specification |
Yes. This Rosco BCG is chambered for 5.56 NATO and is compatible with any standard 5.56 upper receiver. It's also compatible with 300 BLK uppers if you run that caliber.
Yes. The Rosco phosphate BCG is engineered and tested to handle full-auto fire rates, so it's built robust enough for whatever semi-automatic use you'll put it through.
The BCG ships with an upgraded Sprinco extractor kit, giving you a complete, ready-to-install bolt carrier group. No additional components are needed for a standard build.
Phosphate is a traditional, mil-spec finish that resists corrosion and provides a classic appearance. Rosco also offers a nitride-coated version if you prefer that coating; check specs on the nitride model for material differences.
SKU: 167516333 • Width: 1.25in • Height: 1.25in • Depth: 8in • Weight: 1oz