Polymer80Gun.com Premium Billet 80% Lower Receiver – Fire/Safe Marked

$77.00

This isn’t just another 80% lower. This is our shop-favorite billet model, machined from solid 6061-T6 aluminum and built to save you serious headaches during your build. We listened to builders who were tired of fighting roll pins and designed a smarter solution.

The key is in the threading. We’ve added precisely threaded holes for both the bolt catch release and the rear takedown pin detent. This means you install these critical parts with a simple hex wrench—no more hammering, no more flying springs, and no marring your finish. It’s a cleaner, faster, and more secure installation right out of the gate. All necessary screws are included.

We start with a solid block of U.S.-sourced aluminum, not a forging. The billet process allows for a sharper, more defined look and lets us integrate a heavy-duty trigger guard that won’t snap. The magwell is professionally broached for smooth, reliable magazine changes every time. The finish is a durable Type III Hardcoat Anodizing in a matte black that stands up to hard use.

This receiver is Fire/Safe marked for correct selector orientation and is 100% mil-spec where it counts. It’s compatible with 5.56/.223, 300 Blackout, and 6.5 Grendel uppers, giving you the flexibility to build what you want. The fit with standard upper receivers is exact.

If you’re looking for a premium, American-made 80% lower that prioritizes intelligent design and easier assembly without sacrificing durability, this is the one. It’s built for the builder who appreciates smart engineering.

Specifications & Details:

• Compatibility: 5.56/.223, 300 BLK, 6.5 Grendel
• Material: Billet 6061-T6 Aluminum
• Finish: Type III Hardcoat Anodized (Matte Black)
• Fitment: 100% Mil-Spec
• Key Feature: Threaded bolt catch & rear takedown detent holes (screws included)
• Feature: Integrated, heavy-duty trigger guard
• Feature: Broached magwell
• Markings: Fire/Safe Selector Engraving
• Origin: 100% Made in the USA

Note: This is an 80% lower receiver. It is not a firearm and requires machining and assembly to complete. Purchaser is responsible for compliance with all federal, state, and local laws.