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

For builders seeking a precise and compliant path to a large-frame AR platform, this kit provides the essential components for completing a Polymer80 80% lower receiver and jig kit (LR-308). Designed for the .308 Winchester / 7.62 NATO platform, this un-machined lower receiver and accompanying jig system allow you to mill, drill, and assemble your own firearm from the ground up. The kit includes the proprietary Polymer80 jig, which integrates drill bushings and alignment guides specifically for the LR-308 geometry, reducing the margin for error during the machining process.

Overview

This build kit is centered on the Polymer80 80% lower receiver and jig kit (LR-308), which is a semi-finished lower receiver that requires final machining to complete. The receiver is constructed from a reinforced polymer blend, designed to interface with standard LR-308 / DPMS pattern upper receivers and parts kits. The included jig is a single-use, multi-stage tool that guides the user through the critical pocketing and pinning steps. This kit does not include an upper receiver, barrel, trigger group, or any serialized components; it is intended for use by individuals who are legally permitted to manufacture a firearm for personal use.

Features & Specs

The engineering behind this kit focuses on repeatable alignment and material removal for the fire control pocket and trigger pin holes. The jig features hardened steel drill bushings that are positioned according to LR-308 specifications, and the receiver body includes molded-in locating points for the jig attachment.

• Manufacturer: Polymer80. Category: Build Kits. Frame size: LR-308 (large frame, .308 caliber)
• Jig includes: 3-axis alignment pins, drill bushings for 0.125-inch and 0.250-inch holes, and a pocket routing template for a standard AR-10 fire control group.
• Receiver material: Proprietary Nylon 6/6 reinforced with glass fiber. Compatible with DPMS pattern high-profile upper receivers.

When you purchase a polymer80 80% lower receiver and jig kit (lr-308), you receive the lower receiver, the complete jig system, drill bits, end mill, and installation hardware. The jig is designed for a single build and should not be reused due to wear on the bushings. The receiver is marked “80% complete” and does not meet the definition of a firearm under the Gun Control Act until material is removed from the trigger pocket and pin holes are drilled.

Who It’s For

This kit is suited for the experienced hobbyist or gunsmith who has access to a drill press or handheld router with a 1/4-inch collet. It is not intended for first-time builders without prior experience in metal or polymer machining. The polymer80 80% lower receiver and jig kit (lr-308) is a project for those who understand the legal and mechanical requirements of completing a firearm from an 80% blank. Users must verify their local, state, and federal laws regarding the manufacture of unserialized firearms before purchase. This product is not returnable once the packaging is opened due to the nature of the jig and receiver set.

• Requires: Drill press or router, 1/4-inch collet, safety glasses, and calipers for depth measurement.
• Estimated build time: 2-4 hours for the machining process, plus assembly of lower parts kit.
• Compatible lower parts kits: Standard LR-308 / DPMS pattern pivot pins, trigger pins, and buffer retainer.

Shipping & FFL

This product ships directly to your residence or business address. Because this is an 80% receiver, it is not considered a firearm by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) when in its un-machined state. Therefore, no Federal Firearms License (FFL) transfer is required for shipment. However, you must comply with all applicable state and local laws regarding the possession and completion of unserialized firearm components. Some states and municipalities restrict or prohibit the purchase of 80% receivers; it is your responsibility to ensure legal compliance before ordering. By completing this purchase, you confirm that you are legally eligible to possess and manufacture a firearm under federal and state law. No background check is conducted by the seller for this item, and no FFL transfer fee applies.

• Ships via UPS Ground or FedEx Home Delivery. Signature may be required.
• Cannot ship to PO boxes. Must ship to a physical street address.
• No FFL transfer required. No waiting period applies to the receiver itself.