RL556v3 80% AR15 Lower – Gray

About this product

The RL556v3 80% AR-15 Lower is a forged 7075-T6 aluminum receiver in Titanium Gray Cerakote that requires final machining by the end user. This is a military-spec foundation for a custom build, not a finished firearm. You'll need a jig, tools, and knowledge to complete the fire control group pocket, trigger pin holes, and safety selector hole before it can accept upper receivers or parts kits.

What is the RL556v3 80% Lower used for?

This receiver serves as the legal starting point for building a custom AR-15 rifle or pistol that you will finish yourself. You use a milling jig to complete the remaining 20% of machining—specifically the fire control group pocket and pin holes—which transforms it into a functional lower receiver. After machining, you install a lower parts kit, buffer assembly, and stock, then mate it with a completed upper receiver assembly to create a functioning firearm.

How does the RL556v3 compare to a billet 80% lower?

The forged RL556v3 is stronger and more impact-resistant than most billet alternatives, including our own 308 80% Lower – Billet. Forged 7075-T6 aluminum has grain lines that follow the receiver's contours, providing superior tensile strength (approximately 83,000 psi) compared to the machined-from-block structure of billet receivers. The RL556v3 is better for hard-use builds where absolute receiver integrity under stress is non-negotiable, while billet receivers typically offer more aggressive aesthetic styling and unique features at the cost of some material strength.

What does it weigh and what are the dimensions?

The raw receiver weighs 9.8 ounces (278 grams) and measures 9.125 inches long, 2.25 inches wide at the magazine well, and 1.75 inches tall at the buffer tube extension. The critical fire control pocket area has approximately 0.180 inches of remaining material to mill through, which requires precise depth control during finishing. These dimensions are held to Mil-Spec tolerances of +/- .005 inches, ensuring compatibility with standard AR-15 upper receivers and components.

Who is this NOT for?

This product is not for first-time builders without access to proper milling equipment or jig experience. If you cannot maintain perpendicularity within .002 inches over the length of the receiver or lack a properly aligned jig, you will ruin this part. It is also not for anyone seeking an immediately functional receiver—this requires about 45-90 minutes of precise machining work with a drill press or mill, plus additional time for deburring and final fitting.

What's in the box?

You receive precisely one 80% lower receiver, nothing else. There is no jig, no drill bits, no end mills, and no lower parts kit included. The receiver comes with a threaded bolt catch roll pin installed, but you must supply all other hardware, fixtures, and cutting tools. For the machining operation, you'll specifically need a 5/16" end mill like our 5/16″ High Speed End Mill for Easy Jig® Gen 2, a drill press or mill with at least 3 inches of vertical travel, and a vise capable of holding the jig securely.

Is the RL556v3 worth it at $0?

At a listed price of $0, this represents exceptional value for the raw material and Cerakote finish alone, but the true cost is in the required tooling and expertise. A forged 7075-T6 blank with this finish typically costs $120-150 from other vendors, making this a substantial entry point savings. The value proposition hinges entirely on your access to proper milling equipment and your confidence in executing a precision machining operation—if you have those, this receiver provides a professional-grade foundation at minimal material cost.