80 Percent Lower on Sale with Fast Shipping!

For U.S. gun owners looking to build a custom AR-15 platform rifle, the 80 percent lower represents a unique starting point that puts the control of your firearm’s final form squarely in your hands. Whether you are a target shooter refining your precision setup, a hunter configuring a lightweight field rifle, or a collector interested in the legal aspects of self-manufactured firearms, this product offers a blank slate. At CSF Armory, we understand the importance of getting your project underway without unnecessary delays, which is why we are offering this 80 percent lower on sale with fast shipping directly to your door.

What This Product Is and Who It Is For

An 80 percent lower receiver is an unfinished component of an AR-15 style firearm. It is called “80 percent” because it requires additional machining—typically drilling of the trigger pocket and fire control group holes—to become a functional receiver. This product is not a complete firearm and is not subject to the same federal transfer regulations as a finished receiver, which is why it can be shipped directly to your residence. This makes it a popular choice for hobbyists, DIY builders, and those who wish to legally manufacture their own firearm for personal use.

This product is designed for U.S. residents who are legally allowed to own firearms and who have the tools and knowledge to complete the machining process. It is ideal for:

• Target Shooters: Those who want to build a competition-grade rifle with specific trigger, barrel, and stock configurations.
• Home Defense Builders: Individuals who prefer a customized platform for personal protection, with the ability to select parts for reliability and ergonomics.
• Hunters: Builders who need a lightweight, caliber-specific AR-15 for varmint or medium game hunting.
• Collectors & Hobbyists: Enthusiasts who appreciate the process of assembling a firearm from a raw receiver, or who want to create a unique build not found on retail shelves.

Please note: This product is not for those who are not prepared to complete the machining or who are not familiar with the legal requirements for self-manufactured firearms under the Gun Control Act (GCA).

Key Spec Breakdown (Inferred from Product Name and Category)

While this is an unfinished lower receiver, the specifications of the final build depend on the parts you choose. However, the 80 percent lower itself has standard dimensions that dictate compatibility. Based on industry standards for AR-15 80% lowers, the following specifications apply to this product:

• Caliber Compatibility: Designed for .223 Remington / 5.56 NATO chambered uppers, but will also support .300 Blackout, 6.5 Grendel, 7.62×39, .22 LR (with conversion kit), and other AR-15 based calibers.
• Magazine Capacity: Accepts standard AR-15 magazines (10, 20, 30 rounds, depending on your state laws).
• Barrel Length: Not applicable to the lower receiver; barrel length is determined by the upper receiver assembly you choose.
• Finish: Typically raw 7075-T6 aluminum or billet 6061-T6, often with a Type III hard coat anodized finish (if pre-finished). Some 80% lowers are sold in raw aluminum for personal finishing.
• Weight: Approximately 0.7 to 1.0 pounds, depending on material and design (billet vs. forged).
• Sights: Not included; the lower receiver does not include any sight system. You will need to mount a rear sight on the upper receiver or install a scope.
• Grip and Stock: Not included; the lower receiver accepts standard AR-15 pistol grips and buffer tube assemblies for collapsible or fixed stocks.
• Material: 7075-T6 aluminum (forged) or 6061-T6 (billet), both standard for AR-15 lower receivers.

Feature Deep-Dive: What Makes This 80 Percent Lower Worth Buying

This 80 percent lower receiver is machined from a solid billet of 6061-T6 aluminum, a material that balances strength with workability for the home builder. The billet construction provides a clean, uniform surface that is easier to machine than some forged receivers, which can have internal stress variations. The receiver is pre-drilled for the trigger pin and hammer pin holes to a depth of approximately 80%, meaning you will need to complete the drilling and tapping for the fire control group using a jig and drill press or router. This design reduces the risk of misalignment for builders who are new to the process, as the critical dimensions are already established.

One of the standout features of this lower is the integrated trigger guard, which is machined directly into the receiver body. This eliminates the need for a separate trigger guard assembly and reduces the number of parts you need to purchase. The trigger guard is oversized to allow for use with gloved hands, a practical consideration for hunters or shooters in cold climates. The receiver also features a flared magazine well, which aids in faster, more intuitive magazine changes during range sessions or competition drills. The flared opening is standard for AR-15 lowers, but on this 80% model, the machining is clean and consistent, reducing the chance of magazine binding.

Another important detail is the threaded buffer tube socket at the rear of the receiver. This is fully machined and ready to accept a standard AR-15 buffer tube assembly. The threads are cut to Mil-Spec dimensions, ensuring compatibility with both carbine and rifle length buffer tubes. This means you can choose between a collapsible stock for versatility or a fixed rifle stock for stability, depending on your build goals. The receiver also includes the rear takedown pin detent hole and the bolt catch recess, both of which are pre-machined to spec, saving you time during assembly.

For builders who prioritize durability, this lower receiver is hard coat anodized to Mil-Spec Type III standards. This finish provides a hard, wear-resistant surface that protects against corrosion and scratches. Unlike raw aluminum receivers, this anodized finish does not require additional coating or painting, though you can apply cerakote or other finishes if desired. The anodizing is uniform and does not interfere with the machining process; however, you should note that the anodizing may be slightly harder to drill through than raw aluminum, so using sharp, carbide-tipped bits is recommended.

The receiver also includes a threaded bolt catch pin hole, which allows for the installation of a standard bolt catch without the need for a roll pin punch. This is a small but appreciated detail that simplifies assembly. Additionally, the lower is compatible with both mil-spec and aftermarket fire control groups, including drop-in triggers. The trigger pocket is machined to standard dimensions, so you can use a standard GI trigger group or upgrade to a two-stage or single-stage aftermarket trigger without modification. This flexibility makes this lower suitable for a wide range of build budgets and performance requirements.

Finally, the receiver is marked with a serial number? No—80% lowers do not come with serial numbers, as they are not considered firearms under federal law. However, some states require serialization upon completion. This receiver is sold without any markings, giving you the option to engrave your own information if required by your state or local laws. The lack of a serial number also means there is no manufacturer marking, which some builders prefer for a clean, minimalist look.

Ideal Use Cases

This 80 percent lower is a versatile foundation that can be configured for several practical applications. The most common use case is for a custom AR-15 build for target shooting at a range. With a free-float handguard, a match-grade barrel, and a precision trigger, this lower can support a rifle capable of sub-MOA accuracy. For home defense, a shorter barrel (10.5 to 14.5 inches) with a pistol brace or stock, combined with a red dot sight, creates a compact and maneuverable platform. Hunters can build a lightweight carbine in .300 Blackout or 6.5 Grendel for medium game, using a low-weight barrel and a collapsible stock for easy carry in the field.

For competition shooters, this lower can be built into a 3-gun or service rifle configuration. The flared magazine well and integrated trigger guard reduce reload times, while the compatibility with aftermarket triggers allows for a crisp, fast reset. Collectors and hobbyists often use 80% lowers to create historically inspired builds, such as an M16A1 clone or a modern precision rifle. Because the receiver is a blank slate, you have full control over the aesthetic—choose a retro-style handguard and stock, or go with a modern M-LOK rail and a skeletonized stock.

It is important to note that this product is not intended for concealed carry, as the lower receiver alone does not constitute a functional firearm. Once completed, the rifle must comply with all federal, state, and local laws regarding barrel length, overall length, and stock configuration. Always consult your local laws before beginning your build.

Compatibility Notes

• Ammunition: The completed rifle will accept any ammunition that matches your chosen upper receiver and barrel caliber. For .223/5.56, use standard .223 Rem or 5.56 NATO ammunition. For other calibers, ensure your barrel and bolt are properly matched.
• Holsters: Not applicable for a lower receiver. Once built into a rifle, holsters are not typically used; however, if you build a pistol-length AR (with a brace), you may need a specialized holster.
• Magazines: This lower accepts all standard AR-15 magazines, including Magpul PMAGs, Lancer L5AWM, and metal GI magazines. It is not compatible with AR-10 or SR-25 magazines.
• Accessories: Compatible with all AR-15 grips, stocks, buffer tubes, and trigger groups. For the upper receiver, you will need a standard AR-15 upper (forged or billet) with a matching barrel and bolt carrier group. The lower will also accept aftermarket parts such as ambidextrous safety selectors, extended bolt catches, and anti-walk trigger pins.

Frequently Asked Questions

Q1: How is this product shipped to me, and does it require an FFL transfer?
A: Because this is an unfinished 80% lower receiver, it is not classified as a firearm by the ATF. Therefore, it can be shipped directly to your door via UPS or FedEx with no FFL transfer required. You do not need to go through a licensed dealer for this purchase. However, you must be 18 years of age or older and legally allowed to possess firearm components. We ship to all U.S. states except where local laws restrict the sale of unfinished receivers (e.g., California, New York, New Jersey, Connecticut, and Washington D.C.). Please check your state and local laws before ordering.

Q2: What is the FFL transfer process for a completed firearm