The AR15 weapon system is an ever-evolving and modular platform. That weapon system has now been enhanced by Aero Precision into the new M4E1 platform. The M4E1 upper receiver is precision-machined to our specifications and features M4 feed ramps and handguard mounting platform. The rail mounting surface and barrel nut area provide a much stiffer system than a standard receiver, giving you more accuracy out of your rifle. Lightweight by design, stronger through superior engineering, the M4E1 delivers monolithic accuracy in a lightweight package.


  • Forged from 7075 T6 aluminum
  • Precision machined to M4E1 specs
  • M4 feedramps
  • Matte black hard coat anodized Mil 8625 Type 3 Class 2 or Cerakote coating
  • .250" takedown pin holes
  • Laser engraved T-marks
  • Accepts standard AR15/M16 components
  • Handguard mounting platform is forged into the receiver
  • Works with Aero Precision handguards but also fits most BAR-system handguards
  • Comes assembled, with dust cover and forward assist installed
  • Barrel nut and wrench are included

M4E1 Upper Receiver

It all begins with our all new state-of-the-art forged upper receiver. The M4E1 upper receiver is a one-piece design combining the rail's mounting surface with the upper itself.

Lighter design, stronger product

By machining the rail's mounting surface into the upper itself we have condensed the parts needed to mount a free-floated rail to a mere 8 screws. Since it is of the same forging as the upper not only is it a stronger system, but we are able to make even more lightening cuts to save weight and allow for more efficient cooling.

Ease of rail and barrel installation

Simply insert your barrel assembly into the M4E1 upper, tighten it using the provided barrel nut and wrench, slide your rail on and tighten the rail screws. Within minutes you have a modular, free-floated rail.

Near seamless rail & upper alignment

This design removes the human element margin of error when it comes to not only installation, but also correct alignment and removing any gap between the upper and the rail.

Shop M4E1 Stripped Uppers

M4E1 Rails

Choose a rail length and design that matches your shooting style. With how quickly rails can be changed out, we won't blame you if you get two. Plus, our Enhanced Rails are wide enough to fit your suppressor under them - perfect for a short barrel suppressor package.

Enhanced Quad Rail

For the traditional tactician that needs the rail real estate for their tools of trade, or for those that prefer the feel and thickness of a full size handguard, the Enhanced Quad Rail models are for you. Available in 7", 9", 12", 13", and 15" lengths.

Enhanced Keymod Rail

With the absence of full time picatinny rails you get a slimmer profile, significant weight savings, and the freedom of adding accessories how and where you need them. Available in 7", 9", 12", 13", and 15" lengths.

Enhanced M-LOK Rail

If you lean towards Magpul product you will most likely be switching at least one of your carbines over to their new M-LOK system. The Enhanced M-LOK Rail will be ready soon, shortly followed by a launch of accessories from Magpul. Available in 7", 9", 12", 13", and 15" lengths.

Shop M4E1 Enhanced Rails