Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver Only

Build your next AR-15 platform with a foundation designed for precision and compliance. The Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver Only offers the core component for a custom rifle build, machined from a proprietary glass-reinforced polymer blend that meets or exceeds mil-spec durability standards. As an 80% receiver, this unit requires final machining and assembly by the end user, providing a hands-on approach to firearm construction. For the serious builder, this receiver delivers a clean, reinforced pocket design with integrated trigger guard and flared magwell for efficient reloads. Whether you are starting from scratch or upgrading an existing build, the Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver Only is a direct foundation for a reliable, long-lasting rifle.

Overview

The Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver Only is a semi-finished lower receiver intended for use with standard AR-15 upper assemblies. Manufactured by Polymer80, a trusted name in the firearms industry, this receiver is produced from a high-impact polymer that resists cracking, warping, and environmental stress. The Rhino series features an aggressive textured grip and an integrated trigger guard, reducing overall weight while maintaining structural integrity. This 80% lower receiver is designed for builders who want to complete their own firearm without a serialized component, subject to compliance with all applicable federal, state, and local laws. The RL556V3 is compatible with most mil-spec parts kits and buffer tubes, making it a versatile choice for a wide range of builds.

Features & Specs

• 80% Completion State: Requires final milling and drilling to complete the fire control cavity and pin holes; no serial number is applied by the manufacturer.
• Glass-Reinforced Polymer Construction: Proprietary Nylon 6/6 blend with glass fiber reinforcement provides high tensile strength and impact resistance comparable to aluminum receivers.
• Integrated Trigger Guard: Molded as a single piece with the receiver body, eliminating the need for a separate trigger guard installation and reducing potential failure points.

• Flared Magazine Well: Oversized and beveled opening allows for faster, more positive magazine changes under stress.
• Reinforced Takedown Pin Bosses: Thickened material around front and rear takedown pin holes improves longevity during repeated disassembly.
• Textured Grip Surface: Aggressive stippling on the pistol grip and front strap provides a non-slip hold even in wet or gloved conditions.

• Compatibility: Fits standard AR-15 mil-spec upper receivers, lower parts kits, buffer tubes, and stocks.
• Weight: Approximately 8.5 ounces, reducing overall rifle weight compared to aluminum receivers.
• Color: Black (standard matte finish).

Who It’s For

This product is intended for experienced firearm builders and hobbyists who understand the legal and mechanical requirements of completing an 80% lower receiver. The Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver Only is ideal for those who want to construct a custom AR-15 from the ground up, selecting their own trigger group, stock, and upper assembly. It is also suitable for individuals who prefer the weight savings and ergonomics of a polymer receiver without sacrificing reliability. Builders should have access to a drill press, router, or jig system, along with the necessary skills to complete the machining process accurately. This receiver is not recommended for first-time builders who lack experience with firearm assembly or legal compliance.

Shipping & FFL

This item is an 80% lower receiver and does not require transfer through a Federal Firearms License (FFL) dealer for shipment, as it is not considered a firearm under federal law until fully machined. However, the purchaser must comply with all applicable federal, state, and local laws regarding the completion and ownership of unserialized firearms. Some states and localities have specific restrictions or registration requirements for 80% receivers. It is the buyer’s sole responsibility to verify legality in their jurisdiction before ordering. This product ships directly to your address with standard carrier delivery. No signature is required unless requested. Polymer80 RL556V3 – Rhino 80% AR15 Lower Receiver Only orders are processed within one business day, and tracking information will be provided upon shipment.