Aero Precision M5 Apar308003C 308 Lower Strp Blk

The Aero Precision M5 .308 stripped lower receiver is the foundation for building a custom big-bore AR platform rifle from the ground up. If you're ready to assemble your own .308 AR—whether for long-range hunting, precision shooting, or tactical training—this forged aluminum lower gives you a mil-spec platform that plays well with standard AR .308 components and magazines. It ships in anodized black, ready for your upper receiver, lower parts kit, and the rest of your build.

Aero Precision engineered the M5 with practical shooter features that save time and frustration. The upper tension screw lets you dial in the fit between upper and lower without guessing or forcing parts together. The rear takedown pin detent hole is threaded to accept a 4-40 set screw instead of relying on a traditional detent spring, and the bolt catch uses a threaded screw pin rather than a roll pin—both design choices that improve reliability and repeatability. The integrated trigger guard is already in place, and the selector markings are cut to work with 45-, 60-, or 90-degree safety selectors, including Battle Arms Development short-throw designs.

One detail that matters if you're upgrading your grip: the lower receiver is machined with no gap where the grip meets the receiver, so aftermarket pistol grips will fit flush without wobble. Each receiver comes with a nylon-tipped tensioning set screw, but you'll want to grab an Aero Precision M5 lower parts kit separately to complete the build—it includes the custom takedown and pivot pins engineered to work with this platform.

Key Features

• Mil-spec forged aluminum construction in anodized black
• Compatible with standard AR .308 components and .308 magazines
• Upper tension screw for fine-tuning upper/lower receiver fit
• Threaded rear takedown pin detent hole and threaded bolt catch (no roll pins required)
• Integrated trigger guard
• Selector markings compatible with 45°, 60°, and 90° safety selectors
• No-gap grip interface for flush aftermarket pistol grips
• Includes nylon-tipped tensioning set screw

Specifications

Frequently Asked Questions

Will this lower work with my current AR .308 upper receiver?

Yes. The Aero Precision M5 lower is designed to work with standard AR .308 components and will accept any compatible upper receiver built to mil-spec dimensions.

What do I need to complete this build?

This is a stripped lower receiver—it includes only the forged aluminum lower and a tensioning set screw. To finish the build, you'll need a lower parts kit (Aero Precision makes one designed specifically for the M5), an upper receiver assembly, and a stock assembly if you want a complete rifle.

Can I use standard AR safety selectors with this lower?

Yes. The selector markings are cut to work with 45°, 60°, or 90° safety selectors. It's also compatible with short-throw designs like those from Battle Arms Development.

Does this lower have a gap where a pistol grip attaches?

No. The receiver is machined with no gap at the grip interface, so aftermarket grips will sit flush without movement or rattle.