Are 80% or Unfinished Lower Receivers Illegal?

The short answer is no, 80 Lower Receivers are most certainly NOT illegal whatsoever.

Anyone who has never built their own AR-15 may be asking: what the heck is an 80% or unfinished lower receiver?

Well, simply, an unfinished receiver is a piece of metal that is 80% finished, but lacks specific machined qualities that would qualify the metal as a weapon according to the ATF or Bureau of Alcohol, Tobacco, Firearms, and Explosives.

“The ATF has long held that items such as receiver blanks, “castings” or “machined bodies” in which the fire-control cavity area is completely solid and un-machined have not reached the “stage of manufacture” which would result in the classification of a firearm per the GCA.”

The ATF on their website, that can be found if you click the link, has the above statement on their website when it comes to an 80 lower receiver.

Because the piece of metal, that will eventually become a lower receiver, is not yet at the phase that can be classified as manufacturable they are not illegal, and do not require any type of permit or paperwork to buy.

The GCA or Gun Control Act of 1968 does not impoase any type of restrictions for anyone who is wanting to purchase an unfinished lower receiver.

There are many websites that can easily be found through a simple search on any type of search engine operator that will return when you type in 80% lower receivers or unfinished lower receivers.

However, it is important to note that there are requirements for serial numbers and firearms specific markings once the receiver has met a specific level of completion. This can be found at the follow link:  27 CFR § 478.92 (Firearm manufacturers marking requirements).

And there can occasionally be some confusion concerning this topic. Some sites can be found that label their receivers as 80% or unfinished, when in all actuality, they are beyond that level and do require paperwork because the ATF and GCA consider these specific receivers to be at a level higher than 80% towards being completed. And consequently, require a serial number and in turn, a background check and to be transferred and registered in the purchasers name.

Though that fact may make it seem like starting your AR-15 build project to be a little daunting, don’t let it scare you too much away from the completely awesome chance and opportunity to build your own weapon.

Acceptable sites that offer 80% or unfinished receivers should say somewhere on their site that the purchase of their equipment DOES NOT require an FFA.

It also doesn’t hurt to ask someone in their customer service department if their receivers meet ATF and GCA standards. And if they have no idea what the heck you’re talking about, definitely steer clear of that company. It would be more trouble than it is worth.

Another option if you are unsure whether the specific receiver you want is up to code or not is to directly contact the ATF Firearms Technology Branch or FTB. They will be able to help you with this dilemma and advise you whether the receiver is an acceptable and legal option or not.

And keep in mind, as an operator want to build your own weapon for personal use there is NO Criminal Statute against doing so. You can build as many AR-15s as you want, as long as the parts you are purchasing are legally bought and do not violate the GCA or National Firearms Act or NFA. For more information on building your own AR 15, or 80% lowers, visit –

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