Aero M4A1 Clone Complete Lower

The Aero Precision M4A1 Clone Complete Lower is a fully assembled lower receiver built to authentic M4A1 specifications, ready to pair with any standard AR15 upper for a mil-spec inspired build. If you're looking to assemble an M4A1 clone that captures the look and function of the real steel platform, this complete lower comes factory-assembled with all the parts you need to get to the range or field—no gunsmith required, and no hunting through a parts bin.

Aero's Gen 2 lower receiver incorporates thoughtful improvements that matter in actual use. The upper tension screw lets you dial in a custom fit between your upper and lower, eliminating rattle and taking up any play that might develop over time. The flared magwell makes magazine changes faster and more intuitive, whether you're running drills at the range or doing tactical training. The custom Aero Precision markings and authentic M4A1 clone engraving—including "Property of U.S.A.," "MOD M4 CARBINE," and cal. 5.56MM—give this build the correct appearance without compromise.

Everything arrives installed and ready: the standard collapsible stock, A2 grip, receiver extension, carbine buffer kit, and lower parts kit. That means you can focus on sourcing or assembling your upper receiver and getting rounds downrange instead of fussing with assembly. The complete package is ideal for builders who want a verified, quality lower that saves time and cuts the learning curve on AR assembly.

Key Features

• Fully assembled and ready to pair with a standard AR15 upper receiver
• Gen 2 lower receiver with upper tension screw for custom fit and zero rattle
• Flared magwell for faster, easier magazine insertion
• Authentic M4A1 clone markings and Aero Precision custom engraving
• Includes collapsible stock, A2 grip, receiver extension, buffer kit, and lower parts kit
• 5.56 NATO/.223 Remington compatible

Specifications

Frequently Asked Questions

What upper receivers will work with this Aero M4A1 clone lower?

Any standard AR15 upper receiver will fit. The Gen 2 lower's upper tension screw lets you dial in a tight, rattle-free fit with your choice of upper.

Is this lower fully assembled, or do I need to install parts?

It ships fully assembled. The lower parts kit, receiver extension, collapsible stock, A2 grip, and carbine buffer kit are all installed. You only need to match it with an upper receiver and bolt carrier group.

What caliber is this lower chambered for?

The lower itself is 5.56 NATO/.223 Remington. The actual round you fire depends on your upper receiver and barrel selection.

What makes the Gen 2 lower different from earlier versions?

The Gen 2 features an upper tension screw that you can adjust to fine-tune the fit between upper and lower receivers, eliminating play. It also has a flared magwell for faster magazine changes and a sleeker profile.