Polymer80 80% Lower Receiver and Jig Kit (LR-308)

If you have been looking to take on a true hands-on build project for a large-frame AR platform, the Polymer80 80% Lower Receiver and Jig Kit (LR-308) is exactly the kind of challenge that rewards patience and precision. This is not a finished lower — it is an 80% blank that requires you to complete the material removal yourself, giving you full control over the final fit and finish. Whether you are a seasoned builder or someone looking to step up from the AR-15 platform, this kit provides the receiver and the jig you need to get the job done without guesswork.

Overview

The Polymer80 80% Lower Receiver and Jig Kit (LR-308) is designed for builders who want a dedicated large-frame lower that accepts DPMS-pattern LR-308 components. The kit includes the unfinished lower receiver along with the proprietary jig system that guides your drill and router through the critical pocket and trigger areas. Unlike some other 80% kits that leave you sourcing separate tooling, this one arrives with everything needed to complete the lower — minus your own power tools and a little elbow grease. It is a complete starting point for a custom .308 or 6.5 Creedmoor build.

Features & Specs

• Manufacturer: Polymer80 — trusted name in the 80% receiver space, known for durable polymer construction and repeatable jig designs.
• Category: Build Kits — includes the lower receiver, jig, drill bits, end mill, and all necessary hardware for completing the LR-308 lower.
• Platform compatibility: Designed for DPMS-style LR-308 upper receivers and parts kits. Not compatible with AR-10 (Armalite) patterns — verify your components before starting.

This Polymer80 80% lower receiver and jig kit (LR-308) uses a glass-reinforced polymer frame that is both lightweight and impact-resistant. The jig itself is a multi-piece assembly that clamps securely to the lower, providing indexed guides for drilling the trigger pin holes, safety selector hole, and the main pocket. The included end mill is pre-sized for the fire control group pocket, so you do not need to guess at depth or width. Specs are straightforward: the lower is designed for standard LR-308 trigger groups, grips, and buffer tubes. The finished weight is notably less than an aluminum equivalent, making it a solid choice for a lighter hunt or competition rig.

Who It's For

This kit is for the builder who wants to learn the large-frame platform from the ground up. It is ideal for anyone with basic shop skills — a drill press or hand drill, a steady hand, and the ability to follow instructions. The Polymer80 80% lower receiver and jig kit (LR-308) is not recommended for complete beginners who have never completed an 80% lower before; the LR-308 platform has tighter tolerances and more material to remove compared to an AR-15. If you have already built a Polymer80 AR-15 lower and want to move to a bigger caliber, this is the natural next step. It also suits those who want to avoid serialization requirements for a personally built firearm, as the completed lower is not considered a firearm under federal law until it is fully machined and assembled.

Shipping & FFL

Because this item is an 80% lower receiver and not a finished firearm, it does not require transfer through a Federal Firearms License (FFL) holder. It ships directly to your doorstep in all states where possession is legal. However, you are responsible for understanding and complying with all local, state, and federal laws regarding the possession and completion of 80% receivers. Some states and localities restrict or prohibit the ownership of unfinished receivers. Please verify your local laws before ordering. No FFL transfer is needed for this polymer80 80% lower receiver and jig kit (LR-308) — it ships as a non-gun component, but once completed, it becomes a firearm you have built for personal use. We do not provide legal advice; consult an attorney if you have questions about your jurisdiction.

• Free shipping on orders over $150 — this kit qualifies when combined with other parts.
• Orders are processed within 1-2 business days and ship via insured ground service.
• Returns accepted within 30 days for unopened kits only. Once jig components are used, the kit is non-returnable.