About this product

Polymer80 80% Lower Receiver And Jig Kit (Lr-308)

If you are building a large-frame AR-308 platform, the polymer80 80% lower receiver and jig kit (lr-308) provides the essential starting point for a custom, semi-auto build. This kit combines a precision-machined 80% lower receiver with a dedicated, reusable jig system designed specifically for the LR-308 geometry. Unlike standard stripped lowers, this component requires final machining by the builder, allowing for a hands-on approach to firearm construction without a serialized receiver at the point of sale. The kit is engineered for use with mil-spec DPMS pattern LR-308 upper receivers and parts kits, ensuring compatibility with a wide range of aftermarket components.

Overview

The polymer80 80% lower receiver and jig kit (lr-308) is a complete solution for the home builder who wants to complete a .308 Winchester or 6.5 Creedmoor rifle. The 80% lower is molded from a proprietary fiberglass-reinforced polymer, offering a balance of weight reduction and structural rigidity. The included jig is machined from billet aluminum and utilizes hardened steel drill and end-mill bushings. This kit eliminates the guesswork from the machining process by providing indexed tool paths for the trigger pocket, safety selector hole, and buffer tube threads. The jig is designed for multiple uses, allowing builders to complete more than one lower receiver with the same fixture.

Features & Specs

• Manufacturer: Polymer80. Category: Build Kits. The kit includes the 80% lower receiver, the multi-use aluminum jig, drill bits, end mill, and all necessary installation hardware.
• The lower receiver is machined from a glass-reinforced nylon polymer. It features an integral trigger guard, a flared magazine well for easier reloads, and a textured grip surface. The receiver is compatible with DPMS pattern LR-308 upper receivers, buffer tubes, and buttstocks.
• The included jig system does not require a drill press; it is designed for use with a standard hand drill. The jig clamps directly to the lower receiver and provides precise alignment for the fire control group pocket and pin holes.

The polymer80 80% lower receiver and jig kit (lr-308) allows the builder to complete the lower to 100% readiness. The polymer material resists impact and corrosion while remaining lighter than standard aluminum receivers. The jig itself is constructed from 6061 aluminum with black anodized finish. The kit ships with a detailed instruction booklet that outlines each machining step. The buffer tube threads on the lower receiver are pre-tapped to 1-1/16 x 18 TPI, matching the standard LR-308 buffer tube specification.

Who It’s For

This kit is intended for the experienced hobbyist or the first-time builder who has basic mechanical aptitude and access to common hand tools. It is specifically designed for individuals who wish to complete a firearm for personal use and who understand the legal requirements surrounding the manufacture of firearms under the Gun Control Act. The polymer80 80% lower receiver and jig kit (lr-308) is not a finished firearm and is not intended for use by those who are not prepared to perform the final machining steps safely and accurately. Builders should be comfortable reading technical drawings and using a hand drill, a vise, and basic measuring tools. This product is not suitable for commercial manufacturing or for resale as a completed receiver.

Shipping & FFL

Because the polymer80 80% lower receiver and jig kit (lr-308) is classified as an unfinished, non-serialized receiver blank, it does not meet the legal definition of a firearm under federal law. Therefore, this product does not require shipment to a Federal Firearms License (FFL) dealer. It can be shipped directly to your residence or business address. However, it is the sole responsibility of the purchaser to verify and comply with all applicable local, state, and federal laws regarding the ownership and completion of 80% lower receivers. Some states and municipalities have specific restrictions or outright prohibitions on the possession, transfer, or completion of unserialized receivers. By purchasing this kit, you confirm that you are legally permitted to own and complete this product in your jurisdiction. We do not assume any liability for non-compliance with local statutes. All sales are final on this item.