Based on popular carbine configurations, these XM177E2 Upper Receivers are ready for your next Retro build.

The muzzle of the XM177E2 Upper Receiver, is capped by the classic XM177E2 moderator inspired flash hider, with ports around its radius. This muzzle device is a flash hider, unlike the original XM177 muzzle device, which was technically a suppressor.

The flash hider is attached to a lightweight 11.5 or 12.7 inch barrel. Why 12.7 inch? The 12.7 inch model has its muzzle device pinned and welded in place, allowing the overall length of the barrel to reach the required 16” for a rifle.

Barrels are available with a 1-12 or 1-7 twist. Select 1-12 if shooting 55gr bullets, and 1-7 if shooting 62gr or heavier. The front sight base is not F-marked, meaning the round, tapered front sight post is properly in line with the carry handle rear sight. The black carbine handguards closely emulate the original CAR handguards. These barrel assemblies do have a tapered slip ring, which is proper on carbines of this type.

Mounted to the upper is a proper ejection port cover, with a flat external "bump" (not just an off the shelf A2). The receiver is the proper M16A1 style, with a forward assist but no shell deflector. The rear sight is the standard A1 aperture, that can easily be adjusted with a cartridge or tool. Included bolt carrier group is the proper manganese phosphate mil-spec BCG, with chrome lined interior.

Key features of the XM177E2 Complete Upper Receivers:

• M16A1 upper receiver without shell deflector
• XM177 flash hider with proper grenade ring
• 11.5” or 12.7” 5.56x45mm NATO barrel
• 12.7” configuration features a pinned and welded muzzle device, making it 16”+
• 1-12 or 1-7 twist & chrome bore & chamber
• M16A1 ejection port cover
• Tear drop forward assist
• A1 rear sight assembly
• Mag particle and high pressure tested
• Carbine black polymer handguards with heatshields
• Manganese phosphate mil-spec bolt carrier group with Carpenter 158 bolt