Polymer80Market Billet .308 80% Lower Receiver

Build Your AR-10 Right. Build It Tough.

You’re building a .308 for a reason. You need power, reliability, and a foundation that won’t quit. This isn’t a cast or forged part. This is a precision-machined billet 6061-T6 aluminum lower receiver. We start with a solid block of aircraft-grade aluminum and CNC machine it into one of the most robust lowers you can get for your LR-308 or AR-10 pattern build.

The finish is a hard-anodized black. It’s not for looks—it’s armor. It protects against corrosion and wear, so your lower stays solid range after range. We’ve included key features that matter: a fully broached magwell for smooth, reliable magazine changes and a heavy-duty, integral trigger guard that’s part of the billet itself. No flimsy pins or breaks here. The bolt catch hole is pre-threaded for a cleaner install (threaded pin required, included in our recommended LPK).

Important Note: This is an 80% lower receiver. It is NOT a firearm and requires machining to complete. It is NOT marked with Fire or Safe engravings. You are the builder. You are the manufacturer. Know your federal, state, and local laws before purchasing or starting your build.

Specifications & Details:

• Platform: .308 / LR-308 / AR-10 Pattern
• Material: Billet 6061-T6 Aluminum
• Finish: Type III Hardcoat Anodized Black
• Features: Broached Magwell, Heavy-Duty Integral Trigger Guard, Threaded Bolt Catch Hole
• Fire/Safe Markings: No
• Origin: 100% Made in the USA
• Quantity: 1 Lower Receiver

Builder’s Advice:

.308/AR-10 platforms are notorious for parts compatibility issues. Don’t waste time and money on a generic parts kit that might not fit. For a guaranteed fit and a smooth build, pair this lower with our dedicated LR-308 Lower Parts Kit. It includes the correct hammer, trigger, and the specific threaded bolt catch pin you need for this lower. It just works.

Price: $141.90