Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver Only

The Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver Only is a precision-manufactured, unfinished lower receiver designed for builders who require a durable, lightweight foundation for an AR-15 platform. As an 80% receiver, it allows the end user to complete the machining process at home, offering a legal path to firearm ownership without serialization by a licensed manufacturer. This unit is produced by Polymer80, a respected name in polymer firearm components, and is intended for use with standard AR-15 mil-spec parts kits. The RL556V3 Rhino variant features an integrated trigger guard and a reinforced rear takedown pin boss for increased structural integrity. This is the lower receiver only; all other components must be sourced separately.

Overview

The Polymer80 RL556V3 Rhino is a direct result of Polymer80’s engineering focus on reducing weight while maintaining strength. Unlike aluminum lowers, this polymer unit is corrosion-resistant, significantly lighter, and requires no anodizing or finishing. The 80% design means the fire control pocket, trigger pin holes, and selector detent channels are not fully machined, leaving the end user to complete the final drilling and milling. The RL556V3 is compatible with all standard AR-15 upper receivers and aftermarket parts, making it a versatile base for custom builds. Each receiver is manufactured in the United States from high-impact polymer and includes a jig guide for the completion process.

Features & Specs

This lower receiver is built to meet the demands of a hands-on builder. Key specifications and design elements include:

• Manufacturer: Polymer80 – Category: Parts
• Integrated trigger guard for reduced parts count and improved handling
• Reinforced rear takedown pin boss to prevent stress fractures under heavy use
• Compatible with all mil-spec AR-15 lower parts kits and standard buffer tubes
• Lightweight polymer construction reduces overall rifle weight by approximately 30% compared to aluminum
• No serialization required upon completion (end user assumes all legal responsibility for compliance)

Additional features include a flared magazine well for faster reloads and a textured grip surface for positive control. The receiver is designed to accept standard AR-15 safety selectors, bolt catches, and magazine releases without modification.

Who It Is For

The Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver Only is intended for experienced firearm builders and hobbyists who possess the tools and knowledge to complete an 80% lower. This product is not for first-time builders or those without access to a drill press, end mill, or router with a jig. It is suited for individuals who want to create a custom AR-15 from the ground up, control every aspect of the build, and avoid the paperwork associated with purchasing a serialized receiver from a dealer. This is a project component, not a finished firearm. The buyer must be legally eligible to own and build a firearm under federal, state, and local laws. The polymer80 rl556v3 – rhino 80% ar15 lower receiver only ships as a non-gun component and does not require an FFL for transfer, but final assembly must comply with all applicable regulations.

Shipping & FFL

This item is an 80% lower receiver and is classified as a non-gun component under federal law. It ships directly to your door with no FFL transfer required. No background check is needed for purchase. However, it is your responsibility to verify that completion of this receiver into a functional firearm is legal in your city, county, and state. Some states and localities restrict or prohibit the possession or completion of 80% receivers. We do not ship to addresses in jurisdictions where such items are banned. By purchasing, you confirm you are of legal age to own a firearm and are not prohibited from doing so. All sales are final. For further questions regarding compliance, consult local law enforcement or a firearms attorney before ordering.