AeroPrecision167528949
M4E1 5.56 Assm Uppr Rcvr Gov 10.5'' Bbl Carbine W/7''Hg & Fsb$590.98
Availability: In Stock
Current Stock: Out of stock
The Aero Precision M4E1 5.56 assembled upper receiver with 18-inch rifle barrel and 12-inch Atlas S-One handguard is a complete, ready-to-assemble upper that gives you a lightweight, modern AR platform without the guesswork. Built for shooters who want precision engineering without excess weight, this upper pairs Aero's renowned M4E1 receiver with their latest slim-profile ATLAS S-ONE handguard—a combination that balances strength, modularity, and minimal bulk. Since it ships fully assembled, you can get running faster; you'll just need a bolt carrier group and charging handle to complete your build.
The 18-inch rifle-length barrel is forged from 4150 CrMoV steel with a QPQ finish, chambered in 5.56 NATO with a 1/7 twist rate suited to a wide range of ammunition weights. Rifle-length gas systems typically deliver softer recoil impulse and excellent reliability across the board, making this a sensible choice for dedicated riflemen, competitive shooters, and hunters who value consistency. The barrel comes fitted with a standard A2 flash hider and has been HP and MPI tested to ensure durability and safety.
The 12-inch ATLAS S-ONE handguard is the centerpiece of this build's weight-conscious design. It features front and rear picatinny rails, a hollowed-out center section to shed ounces without sacrificing strength, and indexed grip control grooves at 12 o'clock. You get quick-disconnect sling attachment points at 3, 6, and 9 o'clock positions—practical for slung carries and rapid transitions. The low-profile gas block integration means cleaner aesthetics and a slimmer package without compromise.
The upper receiver itself sports Aero's enhanced forging with a billet-like appearance, refined picatinny profile, M4 feedramps, laser-engraved T-marks, and all hardware installed—including port door and forward assist. Fully compatible with mil-spec barrels and parts, this upper integrates seamlessly into your existing AR ecosystem or serves as the foundation for a new, purpose-built rifle.
| Brand | Aero Precision |
| Product Type | Complete Assembled Upper Receiver |
| Caliber | 5.56 NATO |
| Barrel Length | 18 inches |
| Barrel Material | 4150 CrMoV with QPQ finish |
| Twist Rate | 1/7 |
| Gas System | Rifle length |
| Gas Port | .750 gas block journal |
| Receiver Type | M4E1 Threaded |
| Handguard | ATLAS S-ONE, 12 inches |
| Handguard Profile | M-LOK |
| Handguard Inside Diameter | 1.3 inches |
| Handguard Outside Diameter | 1.5 inches |
| Flash Hider | Standard A2 |
| Feedramps | M4 |
| Compatibility | Mil-spec AR15 upper receivers and barrels; low-profile gas blocks |
| Assembly Status | Fully assembled (does not include bolt carrier group or charging handle) |
This is an assembled upper receiver only. To finish your build, you'll need to add a bolt carrier group (BCG), charging handle, and a compatible lower receiver. The upper itself comes ready to attach.
Yes. The M4E1 receiver and ATLAS S-ONE handguard are fully compatible with mil-spec AR15 barrels, bolt carrier groups, and low-profile gas blocks. The M-LOK handguard accepts standard M-LOK accessories.
The ATLAS S-ONE handguard includes quick-disconnect sling sockets at the 3, 6, and 9 o'clock positions, giving you multiple carry and attachment options.
An 18-inch rifle-length barrel typically provides a longer sight radius, more velocity, softer recoil impulse, and excellent reliability across a broad range of ammunition. This configuration is popular with competitive shooters, long-range enthusiasts, and hunters.
SKU: 167528098 • Weight: 5oz
Availability: In Stock
Current Stock: Out of stock
The Aero Precision M4E1 5.56 assembled upper receiver with 18-inch rifle barrel and 12-inch Atlas S-One handguard is a complete, ready-to-assemble upper that gives you a lightweight, modern AR platform without the guesswork. Built for shooters who want precision engineering without excess weight, this upper pairs Aero's renowned M4E1 receiver with their latest slim-profile ATLAS S-ONE handguard—a combination that balances strength, modularity, and minimal bulk. Since it ships fully assembled, you can get running faster; you'll just need a bolt carrier group and charging handle to complete your build.
The 18-inch rifle-length barrel is forged from 4150 CrMoV steel with a QPQ finish, chambered in 5.56 NATO with a 1/7 twist rate suited to a wide range of ammunition weights. Rifle-length gas systems typically deliver softer recoil impulse and excellent reliability across the board, making this a sensible choice for dedicated riflemen, competitive shooters, and hunters who value consistency. The barrel comes fitted with a standard A2 flash hider and has been HP and MPI tested to ensure durability and safety.
The 12-inch ATLAS S-ONE handguard is the centerpiece of this build's weight-conscious design. It features front and rear picatinny rails, a hollowed-out center section to shed ounces without sacrificing strength, and indexed grip control grooves at 12 o'clock. You get quick-disconnect sling attachment points at 3, 6, and 9 o'clock positions—practical for slung carries and rapid transitions. The low-profile gas block integration means cleaner aesthetics and a slimmer package without compromise.
The upper receiver itself sports Aero's enhanced forging with a billet-like appearance, refined picatinny profile, M4 feedramps, laser-engraved T-marks, and all hardware installed—including port door and forward assist. Fully compatible with mil-spec barrels and parts, this upper integrates seamlessly into your existing AR ecosystem or serves as the foundation for a new, purpose-built rifle.
| Brand | Aero Precision |
| Product Type | Complete Assembled Upper Receiver |
| Caliber | 5.56 NATO |
| Barrel Length | 18 inches |
| Barrel Material | 4150 CrMoV with QPQ finish |
| Twist Rate | 1/7 |
| Gas System | Rifle length |
| Gas Port | .750 gas block journal |
| Receiver Type | M4E1 Threaded |
| Handguard | ATLAS S-ONE, 12 inches |
| Handguard Profile | M-LOK |
| Handguard Inside Diameter | 1.3 inches |
| Handguard Outside Diameter | 1.5 inches |
| Flash Hider | Standard A2 |
| Feedramps | M4 |
| Compatibility | Mil-spec AR15 upper receivers and barrels; low-profile gas blocks |
| Assembly Status | Fully assembled (does not include bolt carrier group or charging handle) |
This is an assembled upper receiver only. To finish your build, you'll need to add a bolt carrier group (BCG), charging handle, and a compatible lower receiver. The upper itself comes ready to attach.
Yes. The M4E1 receiver and ATLAS S-ONE handguard are fully compatible with mil-spec AR15 barrels, bolt carrier groups, and low-profile gas blocks. The M-LOK handguard accepts standard M-LOK accessories.
The ATLAS S-ONE handguard includes quick-disconnect sling sockets at the 3, 6, and 9 o'clock positions, giving you multiple carry and attachment options.
An 18-inch rifle-length barrel typically provides a longer sight radius, more velocity, softer recoil impulse, and excellent reliability across a broad range of ammunition. This configuration is popular with competitive shooters, long-range enthusiasts, and hunters.
SKU: 167528098 • Weight: 5oz