Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver with Jig

The Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver with Jig represents a precise engineering solution for builders seeking a hands-on approach to firearm construction. This uncompleted lower receiver, paired with its dedicated jig system, allows the user to complete the final machining steps necessary to produce a functional AR15 lower. The Rhino series is manufactured by Polymer80, a recognized leader in the 80% receiver market, using high-impact polymer material designed to meet mil-spec dimensions for reliable compatibility with standard AR15 upper receivers and parts kits.

Overview

The Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver with Jig is a purpose-built platform for the builder who values control over the manufacturing process. Unlike a fully completed receiver, this 80% lower lacks the fire control group pocket, trigger pin holes, and selector detent channels, requiring the user to complete these features using the included jig. The jig provides precise alignment guides and drill bushings to ensure accurate hole placement, reducing the margin for error during the finishing process. This unit is designed to accept standard AR15 lower parts kits and buffer tube assemblies, making it a versatile foundation for custom builds.

Features & Specs

• Manufacturer: Polymer80; Category: Parts; Model: RL556V3 – Rhino 80% AR15 Lower Receiver with Jig
• Constructed from impact-resistant, glass-reinforced polymer for durability and reduced weight compared to aluminum receivers
• Includes a complete jig system with hardened steel drill bushings, alignment block, and step-by-step instructions for accurate completion
• Compatible with mil-spec AR15 upper receivers, lower parts kits, and buffer tube assemblies; accepts standard magazines and triggers
• Integrated trigger guard and rear takedown pin detent slot; designed for use with a standard AR15 stock and pistol grip
• Ambidextrous safety selector compatibility; reinforced front pin boss and rear lug for enhanced structural integrity

The RL556V3 – Rhino 80% lower receiver is machined from a proprietary polymer blend that resists impact and environmental stress. The jig system is engineered to guide a standard drill press or hand drill, allowing the user to create the fire control pocket and pin holes with repeatable precision. The receiver features a flared magazine well for faster reloads and a textured grip area for improved handling.

Who It’s For

This product is intended for individuals who possess the technical skills and tooling required to complete a firearm receiver from an 80% state. It is suited for hobbyists, gunsmiths, and builders who prefer to customize their lower receiver’s trigger geometry, safety configuration, and overall fit. The included jig makes this a practical option for those with basic machining experience, including familiarity with drill presses and hand files. The Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver with Jig is also appropriate for builders seeking a lightweight alternative to aluminum lowers without sacrificing compatibility with standard AR15 components. This product is not designed for novice builders without prior experience in 80% receiver completion.

Shipping & FFL

This item is classified as an 80% lower receiver and does not require transfer through a Federal Firearms License (FFL) dealer for shipment within the United States. However, the buyer is solely responsible for understanding and complying with all federal, state, and local laws regarding the possession, completion, and registration of firearms. Some states and municipalities impose restrictions or require serialization of finished receivers. It is the purchaser’s responsibility to verify legality in their jurisdiction before ordering. No FFL transfer is required for this uncompleted receiver, but the completed firearm must comply with all applicable laws. This product ships directly to the customer; no signature may be required depending on carrier policy.