Polymer80 LR-308 80% Lower Receiver

If you are looking to build a custom large-frame AR platform from the ground up, the Polymer80 LR-308 80% Lower Receiver is a solid starting point. This un-machined receiver gives you the freedom to complete your own firearm while keeping the process approachable. It is built for shooters who want a lightweight, cost-effective alternative to aluminum without sacrificing the hands-on experience that comes with an 80% build.

Overview

The Polymer80 LR-308 80% Lower Receiver is a partially finished lower designed for DPMS-pattern .308 builds. It requires you to complete the fire control pocket, trigger pin holes, and other critical areas using basic tools and a jig. Because it is made from reinforced polymer, it shaves off significant weight compared to standard billet or forged aluminum receivers. This lower is compatible with most LR-308 and AR-10 components, making it a versatile foundation for a hunting rig, long-range target rifle, or backup patrol build. Keep in mind that because it is an 80% receiver, it is not considered a firearm by the ATF until you finish machining it—meaning no serial number or FFL transfer is required at purchase.

Features & Specs

This Polymer80 LR-308 80% Lower Receiver is engineered for durability and ease of completion. It uses a high-impact, glass-reinforced nylon polymer that resists cracking and handles the recoil of a .308 cartridge well. The integrated trigger guard is molded directly into the lower, saving you the hassle of installing a separate one. Here are the key specs and features:

• Manufacturer: Polymer80
• Category: Parts
• Material: Reinforced polymer (glass-filled nylon) for reduced weight and corrosion resistance
• Compatibility: DPMS-pattern LR-308 and AR-10 upper receivers, parts kits, and buffer tubes
• Requires standard 80% jig and basic tools (drill press or hand drill) for completion

• Integrated trigger guard eliminates a separate installation step
• Reinforced rear takedown pin lug adds strength where it matters most
• Accepts standard AR-15 grip, stock, and buffer tube (using Aero Precision or DPMS-style buffer system)
• No serial number required—this is an unfinished receiver until you machine it

• Weight savings: roughly 30% lighter than a comparable aluminum lower
• Ambidextrous safety selector cutout ready for aftermarket controls
• Flared magwell for faster reloads under stress or in competition

Who It’s For

This Polymer80 LR-308 80% Lower Receiver is ideal for the DIY-minded shooter who wants to build a .308 platform without the premium price tag or weight of metal. It is perfect for someone comfortable with minor machining and assembly work, whether you are a first-time builder or a seasoned hobbyist. Hunters will appreciate the lighter carry weight on long treks, while target shooters can use the savings to invest in a better barrel or optic. It is not recommended for high-round-count competitive use where an aluminum lower might hold up better over tens of thousands of rounds, but for a practical, budget-conscious build, it hits the mark.

Shipping & FFL

Because the Polymer80 LR-308 80% Lower Receiver is an unfinished 80% receiver, it does not require transfer through a Federal Firearms License (FFL) dealer. It ships directly to your doorstep with no additional paperwork or background check required at the time of purchase. Please confirm that possession of 80% receivers is legal in your state, city, or municipality, as local laws vary. We are not responsible for any legal restrictions or confiscations. Standard shipping rates apply, and we typically process orders within one business day. If you have questions about compatibility or shipping, feel free to reach out before ordering.