Brownells Xm177E2 Upper Receiver, 11.5'', 1-7 Twist, Black

Building a retro AR carbine? The Brownells XM177E2 upper receiver in 11.5" with 1-7 twist gives you the correct profile for authentic Vietnam-era inspired configs without compromise. This 11.5" barrel sports the classic XM177E2 moderator-style flash hider—the port-vented design that defined the platform—and pairs it with a 1-7 twist that handles 62-grain and heavier ammunition reliably. It's the short-barreled foundation serious retro builds are built on.

The receiver itself is the proper M16A1-pattern upper without a shell deflector, staying true to period-correct details that matter to builders who know the history. You get the teardrop forward assist, A1 aperture rear sight, and a flat-profile ejection port cover—not some generic aftermarket substitute. Black carbine handguards with integral heat shields complete the look and keep your hands safe during sustained fire. The included bolt carrier group is mil-spec manganese phosphate with a 9310 bolt and chrome-lined bore and chamber, giving you the durability and reliability the platform demands.

This upper arrives complete and ready to mate to a compatible lower receiver. The 1-7 twist is your choice if you're running heavier projectiles or want the flexibility to shoot the full range of modern 5.56 NATO ammo. Whether you're assembling a clone-correct build or just prefer the proven short-barrel carbine profile, the components here won't let you down.

Key Features

• 11.5" barrel with 1-7 twist for 62gr and heavier 5.56 NATO rounds
• XM177E2 flash hider with correct ported design
• M16A1 upper receiver without shell deflector
• A1 aperture rear sight and teardrop forward assist
• Carbine-profile black polymer handguards with heat shields
• Mil-spec manganese phosphate bolt carrier group with chrome-lined bore
• Complete upper receiver assembly ready to pair with lower receiver

Specifications

Frequently Asked Questions

What twist rate should I choose for my ammunition?

This model comes with a 1-7 twist, which is the right choice if you're shooting 62-grain or heavier 5.56 NATO rounds. The 1-7 twist also handles the full spectrum of modern ammunition reliably.

What lower receiver does this upper work with?

This upper receiver is M16A1 pattern and will mate with any compatible AR-15 or M16-pattern lower receiver. Confirm your lower's compatibility with 5.56 NATO ammunition.

Does this come as a complete assembly?

Yes. The upper receiver arrives fully assembled and ready to pair with a lower receiver. It includes the bolt carrier group, barrel, flash hider, sights, handguards, and ejection port cover.

Is the flash hider pinned or welded?

On this 11.5" model, the XM177E2 flash hider is not pinned and welded; the muzzle device is removable. (Note: Brownells also offers a 12.7" version with pinned and welded muzzle device for 16"+ overall length compliance if needed.)