Aero Precision M4E1 Threaded Barreled AR-15 Upper 5.56 Rifle Atlas R-One - 18"
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Aero Precision
Overview
The Aero Precision M4E1 Threaded Barreled AR-15 Upper features an 18" barrel designed for the 5.56 NATO caliber, making it suitable for a range of shooting applications. With a rifle-length gas system, this complete upper receiver offers reliable cycling and performance, while the 1:7 twist rate stabilizes a variety of bullet weights for improved accuracy. This upper commonly appears in builds that prioritize versatility and precision, particularly those utilizing the 5.56 NATO cartridge.
Specifications
Aero Precision M4E1 Threaded Barreled AR-15 Upper 5.56 Rifle Atlas R-One - 18"
Available Merchants(5)
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August 2026 on GunPartPicker
Aero Precision M4E1 Threaded Barreled AR-15 Upper 5.56 Rifle Atlas R-One - 18" ranked #28 of the 690 upper receivers builders added on GunPartPicker in August 2026, behind the Daniel Defense 11.5" 5.56 NATO 1:7 Carbine AR-15 Complete Upper - 10" MFR XS M-LOK Rail, with about 1 in every 167 upper receivers added to builds. Up from #39 in July. Builds with this upper receiver are nearly all chambered in 5.56 NATO, nearly all on rifle-length gas, and nearly all AR-15.
It was out of stock everywhere we track for all of August 2026, and today none of the 5 retailers we track has it in stock right now. Listed prices start at $599.99 at Brownells for when it comes back.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 31 retailers
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Frequently Built With
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Builds Featuring This Part
See all 1 →Builds in the community that include the Aero Precision M4e1 Threaded Barreled Ar-15 Upper 5.56 Rifle Atlas R-One - 18"
| Build | Parts | Total |
|---|---|---|
 | 23 | $2097.20 |
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