80% Lower Fire/Safe Marked – Anodized Black | Polymer80

About this product

Build Your Custom AR-15 with Polymer80’s Original Forged 80% Lower

Experience the foundation of true custom firearm building with our renowned forged 80% lower. Trusted by tens of thousands of enthusiasts, this receiver blank is proudly forged, machined, and anodized in the U.S.A., ensuring unmatched quality and reliability. Featuring a durable matte black anodized finish, it seamlessly matches any upper receiver for a cohesive build. Designed to fit all Mil-Spec parts kits, buffer tubes, grips, magazines, and stocks, it’s the perfect starting point for your AR-15 project.

Key Specifications and Compatibility

• Compatibility: 5.56/.223, 300 BLK, 6.5 Grendel calibers
• Construction: Forged 7075-T6 Aluminum for superior strength
• Finish: Type III Hardcoat Anodizing for corrosion resistance
• Color: Matte Black for a sleek, professional look
• Fitment: 100% Mil-Spec, ensuring broad compatibility
• Fire/Safe Engraving: Pre-engraved for convenience and compliance
• Features: Broached magwell for smooth magazine insertion
• 100% Made in the USA, supporting American manufacturing

What You Need for Assembly

After fabricating your lower, assemble it with essential components: a lower parts kit, buffer tube kit, and an upper assembly. For guidance, follow our step-by-step picture guide or refer to the Ultimate Guide on How to Build an AR-15. New to building? Learn more in our FAQ: What Is An 80% Lower?

Why Choose Polymer80?

With years of expertise and a commitment to quality, Polymer80 delivers products that empower builders to create reliable, custom firearms. This 80% lower is a testament to our dedication to innovation and customer satisfaction, making it a top choice for DIY gun enthusiasts.