Description

Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver with Jig

If you are building an AR-15 from the ground up and want a project that blends hands-on craftsmanship with reliable performance, the Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver with Jig is a solid place to start. Polymer80 has been a go-to name in the build-your-own community for years, and this Rhino series lower receiver continues that tradition. It arrives as an unfinished 80% lower, meaning you get to complete the final machining steps yourself using the included jig. No serial number, no paperwork, and no FFL transfer required at purchase. Just you, your tools, and a clean slate to build a custom rifle that fits your preferences.

Overview

The Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver with Jig is designed for builders who want a lightweight, corrosion-resistant polymer lower that still holds up to hard use. Unlike standard aluminum lowers, this one uses a reinforced polymer frame that reduces weight without sacrificing structural integrity. The kit comes with the lower receiver, a reusable jig, and all necessary hardware to complete the build. It is compatible with standard AR-15 upper receivers, parts kits, and magazines, so you are not locked into proprietary components. Whether you are a first-time builder or a seasoned enthusiast, this lower gives you a straightforward path to a finished rifle.

Features & Specs

• Reinforced polymer construction with integrated steel trigger pin and hammer pin inserts for durability and long-term reliability
• Complete jig system included with drill bits, end mill, and step-by-step instructions to finish the lower at home
• Compatible with mil-spec AR-15 lower parts kits, buffer tubes, and pistol grips for a truly custom build

The jig in this kit is a standout feature. It is machined from billet aluminum and designed to be reused for future builds, so you get more value than a one-time-use setup. The lower itself has a textured grip area and a flared magazine well for faster reloads. Polymer80 kept the overall design clean and functional, with no extra bulk or unnecessary weight. The RL556V3 – Rhino version also includes an improved rear takedown pin detent retention system that makes assembly less frustrating.

Who It’s For

This kit is for anyone who wants to take an active role in building their AR-15 without dealing with the extra steps of an FFL transfer. If you are a hobbyist who enjoys working with hand tools and drilling jigs, the Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver with Jig gives you a weekend project that ends with a functional lower receiver. It is also a good option for shooters who want a lightweight rifle for range days, hunting, or general target practice. Because you finish the lower yourself, you have full control over the trigger, grip, and stock choices from the start. Just be prepared to spend a couple hours with a drill press or hand drill to complete the fire control pocket and pin holes.

Shipping & FFL

Because the Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver with Jig is sold as an unfinished 80% lower, it is not classified as a firearm under federal law. This means it ships directly to your door without the need for an FFL transfer. No background check, no waiting period, and no trip to a dealer. However, once you complete the machining and turn it into a functional lower receiver, you must comply with all applicable federal, state, and local laws regarding firearm possession and assembly. Some states and localities have specific restrictions on 80% lowers or unserialized firearms, so it is your responsibility to verify the legality of this product in your area before ordering. We ship via UPS or FedEx with adult signature required.