Brownells194200218
Brownells Brn-4 5.56Mm 14.5'' Med Bbl Complete Upper W/13.5'' Handguard$1,218.74
Availability: In Stock
Current Stock: Out of stock
The Brownells BRN-4 5.56mm complete upper receiver is a ready-to-run assembly that lets you build or upgrade an AR-15 without waiting for parts to trickle in. This 16-inch medium-barrel upper arrives fully assembled with a 13.5-inch Midwest Industries handguard, muzzle device, and gas system—all you need is a lower receiver to get shooting. It's the kind of no-fuss solution that appeals to builders who want quality without the assembly headache, and to shooters who just want to get to the range.
Built entirely from new components, the BRN-4 starts with a Faxon barrel in 5.56x45mm NATO with a 1-7 twist and medium profile that strikes a balance between weight and rigidity. The bolt carrier group uses a forged 8620 steel carrier with a precision 9310 tool steel bolt, both headspaced to tight tolerances before and after barrel installation. The upper receiver itself is machined from billet aluminum and finished in matte black hard coat anodizing—a more rigid platform than typical forged uppers, with lengthier barrel nut threads that lock the barrel extension over a larger surface area. Brownells test-fires every upper before it ships, so you may see minor brass marks or fouling as evidence of that QC step.
The 13.5-inch Midwest Industries handguard gives you plenty of mounting real estate with full M-LOK attachment points along its length and a continuous picatinny rail for optics and accessories. The included Magpul ejection port cover and mil-spec charging handle round out the package. For reliable operation, Brownells recommends pairing this upper with an H1 or H2 recoil buffer and carbine recoil spring on your lower, and feeding it quality 5.56x45mm NATO ammunition.
| Caliber | 5.56x45mm NATO |
| Barrel Length | 16 inches |
| Barrel Profile | Medium |
| Twist Rate | 1-7 |
| Muzzle Thread | 1/2-28 |
| Handguard | 13.5-inch Midwest Industries, M-LOK and picatinny |
| Carrier Material | Forged 8620 steel |
| Bolt Material | 9310 tool steel |
| Carrier Finish | Nitride |
| Upper Finish | Matte black hard coat anodizing |
| Included Accessories | Muzzle device, gas block, Magpul ejection port cover, mil-spec charging handle |
This is a complete upper assembly, so you'll need an AR-15 lower receiver to mate it with. Brownells also recommends using an H1 or H2 recoil buffer paired with a carbine recoil spring for optimal operation.
The 16-inch barrel uses a medium profile, which balances weight and heat dissipation while maintaining enough material to resist barrel shift during extended shooting.
A 13.5-inch Midwest Industries handguard with both full-length picatinny rail and M-LOK attachment points, giving you flexibility to mount optics, lights, and other accessories.
Yes. The bolt is headspaced prior to barrel installation, then again after, to ensure proper fit. The entire upper is test-fired and inspected before shipment.
SKU: 194200227 • Weight: 7oz
Availability: In Stock
Current Stock: Out of stock
The Brownells BRN-4 5.56mm complete upper receiver is a ready-to-run assembly that lets you build or upgrade an AR-15 without waiting for parts to trickle in. This 16-inch medium-barrel upper arrives fully assembled with a 13.5-inch Midwest Industries handguard, muzzle device, and gas system—all you need is a lower receiver to get shooting. It's the kind of no-fuss solution that appeals to builders who want quality without the assembly headache, and to shooters who just want to get to the range.
Built entirely from new components, the BRN-4 starts with a Faxon barrel in 5.56x45mm NATO with a 1-7 twist and medium profile that strikes a balance between weight and rigidity. The bolt carrier group uses a forged 8620 steel carrier with a precision 9310 tool steel bolt, both headspaced to tight tolerances before and after barrel installation. The upper receiver itself is machined from billet aluminum and finished in matte black hard coat anodizing—a more rigid platform than typical forged uppers, with lengthier barrel nut threads that lock the barrel extension over a larger surface area. Brownells test-fires every upper before it ships, so you may see minor brass marks or fouling as evidence of that QC step.
The 13.5-inch Midwest Industries handguard gives you plenty of mounting real estate with full M-LOK attachment points along its length and a continuous picatinny rail for optics and accessories. The included Magpul ejection port cover and mil-spec charging handle round out the package. For reliable operation, Brownells recommends pairing this upper with an H1 or H2 recoil buffer and carbine recoil spring on your lower, and feeding it quality 5.56x45mm NATO ammunition.
| Caliber | 5.56x45mm NATO |
| Barrel Length | 16 inches |
| Barrel Profile | Medium |
| Twist Rate | 1-7 |
| Muzzle Thread | 1/2-28 |
| Handguard | 13.5-inch Midwest Industries, M-LOK and picatinny |
| Carrier Material | Forged 8620 steel |
| Bolt Material | 9310 tool steel |
| Carrier Finish | Nitride |
| Upper Finish | Matte black hard coat anodizing |
| Included Accessories | Muzzle device, gas block, Magpul ejection port cover, mil-spec charging handle |
This is a complete upper assembly, so you'll need an AR-15 lower receiver to mate it with. Brownells also recommends using an H1 or H2 recoil buffer paired with a carbine recoil spring for optimal operation.
The 16-inch barrel uses a medium profile, which balances weight and heat dissipation while maintaining enough material to resist barrel shift during extended shooting.
A 13.5-inch Midwest Industries handguard with both full-length picatinny rail and M-LOK attachment points, giving you flexibility to mount optics, lights, and other accessories.
Yes. The bolt is headspaced prior to barrel installation, then again after, to ensure proper fit. The entire upper is test-fired and inspected before shipment.
SKU: 194200227 • Weight: 7oz