Aero Precision M4E1 Threaded Complete Upper, 14.5″ 5.56 Mid-Length Barrel w/ Pinned Epsilon 556SL, 12″ M-LOK ATLAS R-ONE HG – Anodized Black

Aero Precision M4E1 Threaded Complete Upper, 14.5″ 5.56 Mid-Length Barrel w/ Pinned Epsilon 556SL, 12″ M-LOK ATLAS R-ONE HG – Anodized Black

Build a better AR-15 without the hassle of assembling an upper from scratch. This M4E1 Threaded complete upper from Aero Precision comes assembled with a 14.5″ 5.56 NATO barrel running a mid-length gas system and a 12″ ATLAS R-ONE M-LOK handguard, all finished in durable Anodized Black. It installs on any mil-spec AR-15 lower receiver in minutes.

Chambered in 5.56 NATO, it also fires .223 Remington, giving you the widest choice of affordable range and duty ammunition.

Key Features

• M4E1 Threaded receiver: the handguard threads directly onto the front of the upper receiver for a strong, repeatable lock-up without a traditional barrel nut.
• 12″ ATLAS R-ONE M-LOK handguard: a slim, free-floating M-LOK handguard with a full-length top rail for optics and lights.
• Pinned VG6 Epsilon muzzle device: installed to manage muzzle rise and blast.
• Made in the USA by Aero Precision in Lakewood, Washington.

Specifications

• Brand: Aero Precision
• Platform: AR-15
• Series: M4E1 Threaded
• Caliber: 5.56 NATO
• Barrel Length: 14.5″
• Gas System: Mid-Length
• Handguard: 12″ ATLAS R-ONE M-LOK (free-float)
• Forward Assist: Yes
• Finish: Anodized Black
• Made in USA: Yes

Installation

Make sure the firearm is unloaded. Open the pivot and takedown pins on your AR-15 lower, seat the upper’s front lug in the pivot pin hole, close the receivers and push both pins home. Insert your charging handle and bolt carrier group, then perform a full function check before live fire. If you are unsure at any step, have a qualified gunsmith complete the installation.

Compatibility

Designed for mil-spec AR-15 lower receivers, including Aero Precision M4E1 and standard AR-15 lowers. Use standard AR-15 5.56/.223 magazines and a standard 5.56 bolt carrier group.

Frequently Asked Questions

Does this complete upper include a bolt carrier group and charging handle?
No. Like most Aero Precision complete uppers, it ships without a bolt carrier group and charging handle, so you can choose the BCG and charging handle that suit your build.

Will it fit my lower receiver?
Yes, it is built to mil-spec dimensions and fits standard AR-15 lowers, including Aero Precision M4E1 lowers.

What bolt and magazines do I need?
Use standard AR-15 5.56/.223 magazines and a standard 5.56 bolt carrier group.

Is a 14.5″ barrel legal on my build?
Barrels under 16″ are regulated under U.S. federal law. Depending on your configuration this upper may need to be used on an AR pistol, on a registered short-barreled rifle, or with a permanently attached muzzle device bringing overall barrel length to 16″. Check federal, state and local law before purchasing.

Does it ship to my state?
Some states and localities restrict certain firearm parts. It is the buyer’s responsibility to confirm the item is legal where they live before ordering.

Disclaimer

Aero Precision, M4E1, ATLAS, R-ONE and S-ONE are trademarks of Aero Precision. Other brand names are trademarks of their respective owners. Specifications and pricing come from the manufacturer and may change without notice. Product images are for illustration. The buyer is responsible for complying with all federal, state and local laws.