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Buying guns can be confusing enough. Building them? It can get even more complicated. You might be new to this, or you might simply not know all the different rules, regulations, restrictions, and general stuff about amateur gunsmithing and 80% lower receivers. We've taken the top questions customers have asked and put 'em all here for your convenience. If you still need help, or have other questions, please talk to us! We're not just customer service. We build guns and our own products, too. You can call, email, or chat us here.

Getting Started

What is an 80% lower receiver?

An 80% lower receiver goes by a myriad of names: “Unfinished lower”, “80 lower”, “unfinished receiver”, and many more. All those terms typically refer to the same product. The 80% lower gets its named because it is only partially manufactured. The "80%" moniker is arbitrary. Until an 80% lower receiver has had its fire control cavity milled out, it is, by law and found in the Gun Control Act of 1968, not defined as a firearm. However, the ATF likes to ignore actual law and make up their own rules. They say that when a single hole is drilled into the 80% lower receiver, it may be considered a firearm.

We also have a full guide that answers this question (and others) in detail.

What kinds of 80% receivers are there?

There are dozens of receiver and frame blanks available for the AR platform in various calibers, as well as 80% frames for popular handgun makes and models.

This guide compares all 80% lowers and frames.

Are 80% or unfinished firearm receivers illegal?

No. The Bureau of Alcohol, Tobacco, and Firearms (ATF) has clarified that receiver blanks that do not meet the definition of a “firearm” are not subject to regulation under the Gun Control Act of 1968. To ensure products sold are not considered firearms under federal law, individual samples are submitted to the ATF. The ATF then physically inspects and reviews the receiver blank or firearm part and makes an official determination as to whether the unit is considered a firearm. If it is not, then it can be legally sold like any other consumer product under federal law. Some state laws may run counter to this ATF policy and federal law by labeling firearm parts as firearms. This is why we cannot ship our products to all 50 states. Please see "Questions About Ordering" below for further details.

Read the full guide: Are 80% Lowers Legal?

Can guns made from 80% receivers be traced?

An AR-15 and any other firearm built using an 80% lower or 80% frame requires no serialization or paperwork under federal law. Therefore, it is typically impossible to determine the firearm’s origin or history. Some states (like California) require 80% lowers to be serialized before they’re completed. 

Does the ATF know about 80% receivers?

Yes, as they’ve clarified above. However, an 80% lower receiver is NOT a firearm. Therefore, purchasing and owning one does not require the paperwork or regulations that govern the purchase and ownership of a firearm. Click the link provided above to read the ATF’s take on 80% lowers, or, as they call them officially, “receiver blanks”.

What is an FFL?

An FFL is a Federal Firearms Licensee. Licensees are required to document the transfer and sale of firearms in the United States. Only the Bureau of Alcohol, Tobacco, Firearms and Explosives (BATFE) may grant licenses to individuals and businesses. is not an FFL and does not sell firearms.

Where can I find more info about my state laws and 80% lowers?

The NRA website is a great resource for citizens to familiarize themselves with their states laws regarding firearms.

Questions About Ordering

How do I order an 80% lower?

The ordering process is simple. Unlike a firearm transaction, no Form 4473 or other paperwork is required. Under federal law, 80% lowers are not considered firearms and are sold just like any other consumer product. More on state laws below. To purchase, choose your 80% lower from the available options and follow the steps to our secure, online checkout. Order information is protected, encrypted, and private. Our customer service team is available to answer further questions about specific products and order information.

Do I need an FFL to buy or build my 80% lower?

Under federal law, no. An 80% lower receiver is not a firearm so an FFL is not required to buy, ship, or own one. Some states require backgrounds for these receiver blanks, so always check your local and state laws before ordering. You must also confirm you do not live in a state which prohibits the sale and ownership of 80% lowers and receiver blanks. More on that next.

Do you ship to California?

Yes, we do. California has placed certain restrictions on the use of 80% lowers and firearm receiver blanks. Before fabricating a firearm in California, you must first pass a state-sponsored background check and apply for a Unique Serial Number with the California Department of Justice.

Do you sell and ship to my state?

Shipping of various products found on this website are prohibited to some states. These restrictions are also located on our Shipping & Return Policy and are subject to change without notice. We cannot sell our products to the following states:

  • Connecticut
  • Nevada
  • New Jersey
  • New York
  • Hawaii
  • Rhode Island
  • Washington state
  • Washington, D.C.


The information, pictures, text or products presented on this website are not a representation by us, and should not be understood by you, that any product or completed firearm is legal to assemble or own in your state of residence. We encourage each and every builder to perform their own research about the state and federal laws that apply to them. It is your responsibility to understand the law and we encourage you to consult with an attorney or your local ATF representative.

Do you ship to other countries or overseas?

No. Exporting our products outside U.S. soil is against various state, federal, and international laws. There are no exceptions that can be made under any circumstances.

Can I export your products out of the country?

No. According to the ITAR (International Traffic in Arms Regulations) and EAR (Export Administration Regulations) Compliance Statement:

“By ordering any product(s) from website, you certify that you, or third-party entities at your direction, will not sell, transport, ship or transfer outside the borders of the United States, nor to any foreign person*, any product(s) which are export-restricted by U.S. export-control law and regulation, without proper U.S. Government export authorization, licensing, and documentation.

Export-restricted items include, but are not limited to, firearms, ammunition, electronic equipment, certain gear and firearm accessories, weapon-mounted or handheld optical equipment including rifle or handgun scopes, night vision and night vision accessories, holographic sight systems, “red-dot” optics, thermal vision, and tactical lights and lasers, knives, and body armor including vests, helmets and shields.

You must indicate on your order if you intend for an item(s) to be exported. An indication of the desire of exportation in no way compels to assist with export in any way, before or after purchase of an item(s). Export, or attempt to export, any controlled or prohibited items outside of the U.S. without complying with U.S. export control regulations can result in severe civil and criminal penalties and/or constitute a federal crime.

“Foreign Person” under ITAR § 120.16 means “any natural person who is not a lawful permanent resident as defined by 8 U.S.C. § 1101 (a)(20) or who is not a protected individual as defined by 8 U.S.C. § 1324b(a)(3)”, and can mean “any foreign corporation, business association, trust, society, or any other entity or group that is not incorporated or organized to do business in the U.S., as well as international organizations, foreign governments, and any agency or subdivisions of government (e.g. diplomatic missions).”

Who do I reach out to when I have questions about my order?

You can get in touch with our team of experts three ways: Simply fill out our Contact Us form, where you can expect a response within the same business day. Additionally, you can also email us at or call us, 888-920-6630.

Questions About Building

I'm new and have no idea where to begin. Help?!

No worries! We've spent hours compiling information for newbie builders. We've got guides for just about every AR caliber and firearm platform we sell. Check out our top guides below to get started.

AR Build Guides

Handgun Build Guides

How do I complete an 80% lower?

Completing your receiver blank requires some basic hand tools, though no gunsmithing knowledge or custom hardware is required. We also sell the primary tool required for this project, called an 80% jig.

What other tools do I need (besides a jig) to finish my build?

You will need a drill press, at minimum, to fabricate your AR-type 80% lower or 80% handgun frame. Some machinists prefer using a milling machine, which makes for a quicker project. This guide covers all the tools required (and recommended) for completing your lower.

Do 80% lowers and build kits come with a jig?

AR-type billet and forged 80% lowers, and AR-15 rifle and pistol kits do not come with a jig. You must purchase a jig separately. Polymer80 AR-15 80% lowers and some handgun build kits (like the Sig P320 kits) include the required jig.

Do you have a jig that does 5.56 and .308?

Yes! The Elite Builder Jig (Patriot Edition) is capable of machining any mil-spec AR-15 and AR-9 80% lower, as well as any LR-308 (AR-10) 80% lower.

Are your barreled uppers fully assembled?

Yes. All barreled upper receiver assemblies for all AR-type receivers are fully assembled and test-fired for functionality. 

Does my 80% lower come with any kind of warranty?

Products purchased on come with a lifetime warranty against manufacturer and workmanship defects. For more information on refunds, returns and exchanges, simply contact our customer support team. They will assist with your return or exchange. Fulfillment of all warranties is subject to our Shipping & Return Policy.

Do you sell any router-based jigs?

No. We've found many enthusiast machinists and amateur gunsmiths prefer fabricating their receivers using a drill press or milling machine. We believe mill- and drill-based jigs are safer to use, more stable and precise, and typically afford better results.


Compatibility Questions

Which 80% lower or frame do I need to build [X] firearm?

Easy! Check out the links below. They'll direct you to the appropriate build kits, frames, and lowers for the firearm type, make, or model.

Will my aftermarket jig work with your 80% lowers?

If your jig advertises that it is compatible with mil-spec AR-15 receivers chambered in 5.56 NATO/.223 Remington, then it will work with our forged 80% lower receiver, our most popular AR-type receiver. We crafted this receiver with dimensions and a black anodized finish that most closely match the look and feel of a typical military-issued lower receiver (minus that full-auto rear shelf and third pinhole, of course).

Is my 80% lower or frame compatible with [X] part?

Our 80% lowers, 80% frames, and gun-building kits are designed to be compatible with their corresponding "retail" firearm platform. That means your AR-type 80% receiver or build kit will work with other regular commercial, mil-spec AR parts on the market. Your finished P80 ("Glock") frame, 1911 frame, or Sig P320 frame will work with its factory counterpart's available components. Reference our build guides in the previous section for more details about parts compatibility for each caliber and platform.

Can I shoot 5.56 NATO in my .223 Remington-chambered AR?

Modern .223 Remington and 5.56 NATO chambers are rated to handle pressures beyond what either cartridge can produce, and many shooters cross-load NATO rounds in Remington chambers. While this may not cause an immediate catastrophic failure in your new rifle or pistol, cross-loading in this manner may result in early barrel wear, throat erosion, and more felt recoil. It is not officially safe to do, nor is it recommended for the sake of performance.

What's the difference between a billet and forged lower?

Forged receivers are considered mil-spec and are drop-forged from 7075-T6 aluminum. Billet receivers are cut from 6061-T6 billet aluminum bar stock using CNC machines.

This guide compares forged, billet, and cast receivers.

I have more questions!

That is expected and not surprising. This hobby is complicated in more ways than one. We're not just business folks and customer service. We actually build our products, and we shoot (often). We're happy to help answer questions, provide some informed opinions on build specs and features, and troubleshoot challenges you're facing during fabrication or assembly.

Get in touch with us here!

We can talk over the phone, via instant chat, or by email. Please upload photos if emailing about a build or assembly question. It helps us help you more quickly.

We are a national retailer of individual components and not all products depicted on this website are legal in every state. Shipping of various products found on this website are prohibited to some states (such as California, Connecticut, District of Columbia, Hawaii, New Jersey, New York, Rhode Island, and Washington). The information, pictures, text or products presented on this website are not a representation by us, and should not be understood by you, that any product or completed firearm is legal to assemble or own in your state of residence. We encourage each and every builder to perform their own research about the state and federal laws that apply to them. It is your responsibility to understand the law and we encourage you to consult with an attorney or your local ATF representative.