80% AR-15 Lower Receiver Determination Letter from the ATF

Disclaimer: A provision in the Gun Control Act of 1968, 18 U.S.C, Chapter 44 states that an unlicensed individual can make a firearm for personal use, but not for the intent of sale or distribution. Said firearm must conform to N.F.A standards and you must be legally able to be in possession of a firearm. Should you desire to create a Short Barreled Rifle or a Machine gun the BATFE is going to require additional paperwork. If down the road you desire to sell your rifle you will have to put a serial number on it and transfer it via a Federal Firearms License holder. If you never intend to transfer or sell the firearm it must be destroyed upon you giving up possession of the firearm. Granted this is the generally accepted translation of 18 U.S.C, Chapter 44 you should still check local and Federal laws before attempting to build your own personal firearm. Technically you can sell a rifle you have made but you cannot simply make a rifle then immediately decide to turn around and sell it.

Steve Johnson, The Firearm Blog’s Editor and Chief, recently blogged about Polymer80’s recent “proactive” decision to stop selling 80% lowers. Polymer80 noted that they were going to work with the Science and Technology Department of the ATF.

Chris Garrison, owner of Billet Rifle Systems and Billet80.com, provided The Firearm Blog with a copy of His Determination letter from the ATF.

ATF Letter


Hope this clears things up bit concerning 80% lowers. A big thank you to Chris Garrison for sending us his Determination letter.

The Firearm Blog has a series of articles that detail making your own Ar-15 with an 80% lower.

The Editor Says: Given the recent events and uncertainty surrounding 80% lowers, we will publish all BATFE letters determining their legality. Manufacturers and retailers can email their letters to the editor at editor@thefirearmblog.com

Thomas Gomez

Thomas Gomez currently resides in the mountains of central New Mexico. He has an M.B.A, an Ar-15/M16/M4 armorer certification from Specialized Armament Warehouse as well as a Glock armorer certification. Aside from writing for The Firearm Blog he works as a Clinical Analyst for a large Hospital. He spends his free time farming, ranching, hiking, fly-fishing and hunting in the beautiful forests and prairies of New Mexico. He can be reached at LOADTHATBIPOD@gmail.com


  • gunslinger

    but what about “backfilled polymer” lowers?

    • Rob in Katy

      I thought the guys that got raided were NOT backfilling, but pouring the mold around the plug so that there never was a completed lower in the process.

    • sianmink

      I understood that they weren’t backfilled, but in fact molded around the solid FCG cavity blank.

      • echelon

        Yes but we’re dealing with an agency that defines items that are firearms as not firearms and determines that some firearms are so evil that they should be given the designation “Any Other Weapon”. And apparently a 10 inch barrel gun that can shoot rifle caliber rounds in semi automatic fashion is less evil than the same said gun with a stock on it, thus requiring your hard earned money and timely roadblocks to ownership plus registration with the all seeing Eye of Mordor.

        I wish I were making this stuff up, but alas this is the mess we’ve allowed our government to turn into…

        • sianmink

          That’s nothing compared to the firearm import rules.

          • HKGuns

            Most of which are in place to protect the, “mostly”, lazy US firearms industry.

          • echelon

            And yet our government is one of the biggest importers and exporters of military arms in the world. And those guns end up in the hands of many people who they do not intend. So apparently it’s a “do as I say not as I do” kind of thing…

            And apparently Mr. Leland Yee didn’t think these “laws” applied to him!!

        • Eric S

          From a legal standpoint it works in their favor to be vague. The more solid the definition, the more workarounds people will create. Nobody can out think a few hundred million of their peers.

          Besides, gotta keep up that revenue stream somehow.

          • echelon

            Oh for sure. Most people don’t realize but if you study history even the constitution was made more vague than when it was initially drafted. And it was more vague than the Articles of Confederation.

            The final draft of the constitution had to go through the “committee of style” before it could be shown to the public. And even then there was uproar and panic. Ever wonder why the 2A doesn’t just say “People can own firearms and the government can’t make any laws restricting any ownership.”? Those “committee of style” guys had a hand in that…

            Governments have been doing this forever. They have vague down to an art and science.

          • Mystick

            It DOES say that… “The Right of The People to keep and bear arms shall not be infringed.”

            There’s no ambiguity there. It doesn’t say “the right of the state” or “the army”, but The People… which are defined elsewhere in the document.

          • echelon

            Wrong. See how they put all those nifty little clauses in there and all those fun commas? That’s the “style” part. That’s what causes the ambiguity. If there was no ambiguity then why would the Supreme Court have had to make decisions over the years? Why is there any debate at all?

            “A well regulated militia,…” – Hmm that could need some interpreting.

            “…being necessary to the security of a free state, ” – So what if now that we have a standing army and national guard we can say that ownership is no longer needed for this? Again debatable.

            “…the right of the people to keep and bear arms, shall not be infringed.” What people? All people? Government people? militia people? trained people? Again debatable.

            If I were to write it I’d try something more like this: “Human beings have an intrinsic right to defend themselves and their property with any firearm they deem worthy, up to and including any weapon designed by a military force either in the past, present or future. No laws or regulations shall ever be made which would restrict in any way a person’s natural right to self defense with a firearm or for identification or tracking of any firearm, firearm part, ammunition or owner.”

          • Mystick

            “The People” is defined within the preamble. It is not the government or any government entity – The People established The Constitution to define the government. The government did not exist.

          • echelon

            Are you sure about that? Pay attention to the capitalized words. In LAW capitalized words have special meanings that require definitions. I suggest you go get a Black’s Law Dictionary and then go study the constitution and other legal documents. You will be very surprised and how we’ve been bamboozled by the twisting of words and their meanings…

            And if I am wrong then how did we get to where we are today? Our “law”, which is a piece of paper written by dead men, surely didn’t stop any one of our “representatives” from trampling all over the document…

          • z

            tell that to the IRS, ATF and NSA and let me know how far that line of reasoning gets you.

          • Erin Tarn

            “…any firearm they deem worthy…” In your comment, “they” is subjective. By “they,” do you mean the Federal Government?

          • echelon

            Read the full sentence for context: “HUMAN BEINGS have an intrinsic right to defend themselves and their property with any firearm they deem worthy…” Meaning the Human Being. Not some “ruler” or “lawmaker” or “politician”. Not someone who says they’re “your better”.

        • Phil Hsueh

          I was going to say that the SBR law probably has more to do with conceal-ability than actual firepower but then thinking about it I realized that that argument is invalid since it would probably be more difficult to conceal an SBR than a rifle based pistol.

          • echelon

            Indeed. Or the fact that a simple Glock with a 33rd mag is infinitely more concealable than any “rifle based pistol” or SBR…

            Somehow a gun with a 12″ or 14″ barrel is somehow more evil than one with a magic 16″ barrel you know. Oh except shotguns – shotguns are so evil that their barrels have to be 18.5″ or they just get way too evil…like evil beyond imagination. And don’t get me started on those devilish AOWs…those things are in a class by themselves!

    • Paul Epstein

      The inherent problem with the idea of placing a block into the area with the components, even if the material of the receiver is poured around it, is that the actual material of the receiver has already been shaped in the form of the finished 100% firearm even before the filler block has been removed. No more alterations to that material will be made (or can be made). This is not a problem if the person pouring the polymer is also the one making the firearm, because it doesn’t matter at what point they would be making a firearm if it doesn’t change hands before that designation occurs.

      If the block is a separate material and the polymer is correctly formed into the final shape, you’ve now created a firearm even if that material hasn’t been removed yet, because the block itself performed the work of forming the fire control area. That is in fact why it is there, right? If you weren’t using it for that purpose, there’s no legitimate reason to include it in the manufacturing.

      It’s all rules lawyering and the technical branch trying to determine what they can enforce under the current laws without changing them or failing to enforce provisions of them. It doesn’t need to be common sense to be a legitimate reading of the particular law congress thought up.

      • Suburban

        They came under pressure after the “ghost gun” video came out, so they are “doing something.” Period.

        • Anon. E Maus

          Well why the shit would they listen to DeLeon? He’s a fucking idiot, he’s probably the dumbest of all the gungrabbers in office, what could they gain by appeasing him?

          • Suburban

            To silence the gungrabbers writing angry letters to the ATF?

    • gunslinger

      wow, didn’t realize my jokish post would generate such a response. i mainly said this because of the ares raid posted a while ago.

  • Seth Hill

    Ok, hols up. Technically speaking based on what is in the letter; if you consider A and B in the letter, shouldn’t the upper receiver of an AR be considered a “firearm” over the lower? The upper holds the the bolt, firing mechanism, and is threaded for a barrel AND would be much easier to convert to actually fire a round over the lower receiver, which only contains the hammer.

    • echelon

      Yes, but you’re actually expecting the definition of firearm to make sense as they see it when it doesn’t. According to that definition of firearm…look at the last sentence “Such term does not include an antique firearm.” So something called a firearm is not defined as a firearm? So let me get this straight – if I were to defend myself with an “antique firearm” which is not a firearm by definition here, then there should be no repercussions under the law as far its’ use is concerned? Logically this is absurd and why we even put up with this nonsense as a nation is just beyond me…

    • Anon. E Maus

      True, but the lower of an AR is also what “determines” if it’s Rifle, Pistol, Shotgun or Machinegun, as well as having the stock (or lack off). It’s also the part that accepts the magazine.

      It doesn’t really make too much sense, but it is what it is.

  • Austin Gardner

    Best part? The Federal Government doesn’t ship with USPS.

    • An Interested Person

      Yea… I noticed that too. Funny, but sad.

    • Mystick

      Some not-so-subtle irony there…

    • William Baker

      Especially odd since it was determined not to be a firearm, so why no USPS?

      • Aaron

        Because they never use the USPS ever nothing from the BATFE goes through the USPS.

  • BOB

    Why don’t they ship USPS?

    • They probably don’t trust them not to lose it.

    • Thoughtcriminal

      Because then their shipments would be answerable to the US postal inspection service. They routinely ship guns, ammo, drugs and other controlled things, and when they lie on paper and send it somewhere its called mail fraud.

  • Mark N.

    Who cares about this? This is a letter concerning a forged (i.e., aluminum) 80% lower, not a polymer lower. The brouhaha is about polymer lowers, and I assume, from this, that Polymer80 hasn’t submitted a polymer lower for approval.

    • Anon. E Maus

      If it’s regarding Ares Armor, it was something about how they manufactured it that the ATF determined to not be an 80% lower, and legally a firearm, thus they couldn’t legally sell their lowers without being an FFL and running by the NICS system.
      80% lowers aren’t actually illegal (at this point)

  • Skeptikal_Realist

    “If down the road you desire to sell your rifle you will have to… transfer it via a Federal Firearms License
    holder.” – citation needed

    “If you never intend to transfer or sell the firearm it must be
    destroyed upon you giving up possession of the firearm.” – citation needed

  • 191145

    In about a year they will require your customer payment methods and shipping info !

  • Deakon

    Has anyone ever seen an effective crime stopping gun law? Not really. This is less about principle, and more about power in politics. It is time to re-establish the checks and balances, vote out the gov. reps who are clearly for none but themselves, and abolish certain agencies for which we have no need- starting with the BATFE. All we have to do is start talking to each other, to take back our rights. They are the few-WE ARE THE MANY.

  • Mark Are Reynolds Ⓥ

    Blah, blah, blah. Seems that ever since the 1934 Gun Control act someone has never learned the simple meaning of SHALL NOT BE INFRINGED. WHO is damaged by any of this? WHO was damaged by Randy Weaver cutting off a shot gun shorter than “allowed”? WHO was damaged by purchasing a plastic lower receiver that was not milled out? Who is damaged if the serial number can be peeled off in one minute? Why surprise! NO ONE IS DAMAGED BY ANY OF THIS ACTIVITY. Learn your power as a JUROR and refuse to CAGE fellow Americans for VICTIMLESS CRIMES. NO VICTIM. NO CRIME. Who are the CRIMINALS? Those who would CAGE their fellow human beings for doing NOTHING wrong.

  • TC

    Where in the law does it say you must add a serial number prior to sale and where does it say it must be sold through a dealer?

  • davidmdb33

    The Post Office argues about supporting our 2nd Amendment. So short of a completed weapon or to a Licensed FFL holder, the post office will not handle weapons. Fed Ex will handle ammunition, weapons, primers, powder, etc.