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Print Your Own Gun… or Not

by Brian Dunning, Apr 18 2013

RepRap Mendel 3D printer

This is one of those blog posts that will likely be laughably obsolete within a couple of years.

It’s not exactly news that 3D printing technologies have been used to print parts of working guns. So far, the firing chamber still needs to be a piece of real metal, and can be purchased off the shelf; but the main mechanical part — where bullets are loaded and triggers are pulled and shells are ejected — can be printed at home on a common 3D printer. It is this part, usually called the lower receiver, that constitutes the legally controlled “gun”. In other words, the part of the gun that makes it a gun, and that you’re in trouble if you make without being a licensed firearm manufacturer, is the part that’s easiest to print yourself.

As of this writing (which is why I said this post will soon be obsolete) common 3D printers can only make stuff out of various plastic resins. It’s sort of possible to 3D print things out of metal, but it’s a much longer process and requires several additional steps. Metal bits can be deposited along with a resin binder, and the object then has to be infused with metal and baked, a process which requires additional hardware. But at the rate that 3D printing technology is evolving, this probably won’t be the case for very long. Femtosecond lasers are one possible technology that might make for-real metal printing available to the masses without any complicated additional steps. 3D printing already allows the construction of devices replete with moving parts all intact.

So it’s not a terrible argument when the pro-gun lobby says that it’s a fool’s errand to try and ban guns. They’re already here, and they’re going to continue to be easier and easier not just to buy, but to make.

However, one argument against this is that it’s still illegal to make your own gun, just as it’s illegal to sell pirated movies over the Internet. Web server companies that host 3D data files for guns could be open to prosecution, and that’s not trivial. The average Joe Blow can no longer easily launch some freeware program like Napster and easily download any movie or song; you have to have more specialized knowledge, and have to employ knowingly criminal intent to find the right servers and do whatever it is you do. This type of thing will likely keep the 3D gun modeling data very hard to find as well.

Obviously, anyone who really wants to do it will be able to.

However, this is not new to 3D modeling. There are many independent gunsmiths in the world, and many of these are licensed firearm manufacturers. A lot of them build reproductions of classic antique firearms; some build specialized competition weapons. It has always been the case — and will always continue to be the case — that a few simple metalworking tools allow anyone to manufacturer any type of gun they want. You do not need a 3D printer. You do not need to wait for 3D printing to become better. You can, right now, get ahold of some secondhand tooling and manufacture any type of firearm you wish, with nothing more than knowledge and skill. Unlike 3D modeling data files, which are likely to become subject to laws, conventional gun blueprints are widely available in books.

Don’t forget that the Oklahoma City bombing was accomplished with a rented truck, ammonium nitrate fertilizer [Note: this was written prior to the tragic Texas plant explosion on April 17], and nitromethane racing fuel, plus a trigger of commercially available explosive. It is a fool’s errand to try and prevent such attacks by controlling the materials, which, for practical reasons of running a society, must continue to be commercially available. It is somewhat less of a fool’s errand to block legal access to 3D firearm data files. But it remains a fool’s errand to prevent anyone from doing anything with a 100-year-old manually operated gunsmith’s lathe to do whatever they want to do in their basement.

3D gun printing? It’s sensational, it’s alarming, and it makes for great press; but it will never be the only way for criminals to create their own guns.

37 Responses to “Print Your Own Gun… or Not”

  1. David H says:

    Hi Brian,
    Thanks for an interesting, even-handed article on the subject. There is a minor quibble, however. It is perfectly legal to manufacture a firearm for your own use — you start getting into trouble when you start manufacturing for sale, especially if those sales cross state lines. If you do a search for “80% lower receivers,” you will see that there is a thriving market for this. Other than the receiver, pretty much any other part is available without any difficulty whatsoever.

    While there’s no doubt that the plans will eventually be legislated into oblivion, they’re undoubtedly easy to find, and your CNC machine or 3d printer is not likely to care about the provenance of the plans it’s working on.

    Thanks again.

    • Interesting, I was not aware of that difference. Thanks, I will double-check my source.

      • Michael Brady says:


        From the ATF itself…

        “Q: Does the GCA prohibit anyone from making a handgun, shotgun or rifle?

        With certain exceptions a firearm may be made by a non-licensee provided it is not for sale and the maker is not prohibited from possessing firearms. However, a person is prohibited from assembling a non-sporting semi-automatic rifle or non-sporting shotgun from imported parts. In addition, the making of an NFA firearm requires a tax payment and approval by ATF. An application to make a machine gun will not be approved unless documentation is submitted showing that the firearm is being made for a Federal or State agency.

        [18 U.S.C. 922(o) and (r), 26 U.S.C. 5822, 27 CFR 478.39, 479.62 and 479.105]”

        “Q: Is it legal to assemble a firearm from commercially available parts kits that can be purchased via internet or shotgun news?”

        For your information, per provisions of the Gun Control Act (GCA) of 1968, 18 U.S.C. Chapter 44, an unlicensed individual may make a “firearm” as defined in the GCA for his own personal use, but not for sale or distribution.”

      • Have Blue says:

        Speaking as the person who actually printed the lower receiver detailed in the second link (in addition to being a Skeptoid and SGU fan), I can confirm that David and Michael are entirely correct.

        There is no way that I would have 3D printed a firearm receiver (and then blogged about it) had it been illegal!

  2. Bart says:

    Isn’t mass production the actual problem? Hard to make hundreds of guns a day with tools in your basement.

    • Max says:

      Not if we’re talking about “lone wolf” terrorists like Anders Breivik.

    • madscientist says:

      Why would only mass production be a problem? Even a gunsmith turning out one per month can be a nuisance to society.

  3. Old Rockin' Dave says:

    Your point is borne out by the “craft builders” of guns around the world.
    There has long been a tradition of fairly sophisticated firearms manufacture in parts of Asia. In Pakistan, Afghanistan, and other parts of central Asia weapons have been made by village smiths for centuries, edged weapons in the past, firearms now. The quality varies, but some are very good indeed. I recall an article about them some years ago in which an Afghan gunmaker said he could copy even an RPG if he could get the right steel.
    The Philippines has long been trying to cope with what are known as paltik guns, which have been made since Spanish colonial times, and got a boost from the anti-Japanese resistance in World War Two. It was so prevalent in Danao City that ultimately it developed into an aboveground legitimate industry.
    The Israeli arms industry had its start with the underground manufacture of Sten guns, a British World War Two design intended to be made cheaply and with little precision machinery.

    • Daniel says:

      It seems like the examples you mentioned are all borne out of political resistance movements of some sort. If you believe that the murder rate in the US is primarily a legal gun availability problem (FWIW I think it’s a very small part of the problem), underground gun manufacturing is not what you ought to be worrying about, and isn’t really a good argument that all the murderers in the world will find a gun one way or the other.

      I mean, if you theoretically could make Smith and Wesson, and the like, and everything they’ve ever made, disappear from the face of the earth, do you think that your typical gang banger in Chicago or Detroit is going to get a gun that was made from a gun craftsman? Highly unlikely.

      • madscientist says:

        Highly unlikely? If you can stop the supply, odds are someone will learn the craft or at least try to. It’s really not difficult at all; the rifling file is about the only thing they will not likely be able to make on their own, but smooth-bore guns are good enough for a gangster. In other parts of the world I’ve seen makeshift shotguns made with 2 pieces of pipe, a wooden dowel, and a nail. Historically, unlicensed and illegal gunsmiths have thrived around the world (and I’m taking about high quality weapons now, not makeshift shotguns).

      • Old Rockin' Dave says:

        My point is that it is not very difficult to make working firearms, even reasonably sophisticated ones.
        If a village smith in Afghanistan can make a reasonable copy of a Kalashnikov with flywheel-driven tools, or the Polish Armia Krajowa could make Sten guns under the noses of the Nazi occupation, imagine what Americans could make with reliable electricity and readily available and legal machine tools. If there’s a market, someone will supply it, whether it’s to equip gangbangers or to stock up to resist whatever paranoid fantasy is the flavor of the month. Once a cottage industry gunsmith gains the ability to make a simple weapon, it’s likely that he will increase the sophistication and quality of his product as time goes on.
        The danger in this is the “If guns are outlawed, only outlaws will have guns” argument. You could substitute any noun for “guns” in there, “spaghetti”, “binoculars”, anything. I thought that was the point of outlawing things – that someone would have to break the law to get the illegal item. The other fallacy is “knives can kill so why don’t we outlaw knives?”. A dedicated lawbreaker can ultimately get his hands on almost anything, even plutonium, but that doesn’t mean everything should be legal, and firearms are definitely in a different class of dangerous than steak knives.

      • Daniel says:

        You obviously know a lot more about this than I do. But in the villages in Afghanistan, and in Nazi occupied Poland, do you know if there are any informed estimates of the percentage of the total firearms in circulation that are made in the way you describe? Let me know if I’m wrong, but I imagine it was pretty small. The mujahadeen were getting their asses handed to them by the Russians until the US (and Saudi Arabia, and Israel, and Pakistan) started supplying them with arms, which included truck fulls of AK-47s. These days NATO troops are primarily targeted by roadside bombs, the most effective of which contain explosive made for military use. In other words, NATO’s job would be a lot easier if all the enemy had were craftsmans’ guns. So in Chicago and Detroit, I’m sure they could get a few of them, but not all that many to do much damages.

        Also, I’ll note that there’s apples and oranges between saying we prohibit the sale of plutonomium so why not guns. There really is no need for a law abiding citizen to have plutonomium for self defense, hunting. It’s also a little harder for a crazy person to get his hands on some plutonium, much less make destructive use out of it, as it is with handgun. The fact is though, if I lost everything I had, and found myself with no choice but to live in Camden, NJ, I’d do everything I could to arm myself.

      • Old Rockin' Dave says:

        You miss the point: that what there is a market for will usually find some kind of supplier, and that craft-made guns could easily be made here at something like affordable prices for those who want them.
        Obviously, plutonium is a (somewhat) far-fetched example of an item that it is reasonable to ban the ownership of (at least in significant quantity), but the idea that because criminals can make or adapt something to kill people from everyday objects is not a good reason to ban the deadlier items. Criminals still get hold of automatic weapons, shot-load pistols, and sawn-off long guns, even though they all are illegal, but that is not a tenable argument for legalization.

    • And, of course, there’s the guy in Macau whom James Bond visited, and who made Scaramanga’s golden gun.

  4. Daniel says:

    In the United States anyway, about 2/3 of all murders are committed in or around large cities, and primarily by people who lack a high school education. Until we get to the point that 3D printers cost less than $100, that the materials needed to make an operating firearm on a 3D printer are readily available, and guns are easy to “print”, the vast bulk of people that commit murders will not have the means or inclination to acquire firearms in this way. Even if we get to that point, I can’t imagine that it would be more efficient and cost effective for gun manufacturers to mass produce guns using “printers”. I don’t want to sound like the guy in the patent office who said everything that can be invented has already been invented, but this seems like a highly implausible scenario.

    Just one quibble though, I wish people would stop referring to the “pro-gun lobby”. It’s actually voters that oppose laws restricting the ownership of guns. You know, your neighbor, your friend, your relative. The pro-gun lobby, as such, (along with most other lobbies) has a lot less control over things than they get credit for.

  5. Chris says:

    The 3D gun modeling data won’t be hard to find. There a lot of torrent sites like the pirate bay were you can find anything you want. Illegal, of course. Very hard to find, not at all.

  6. madscientist says:

    The precision of these printers (even the high-end commercial ones which can create sintered steel parts) are not good enough to create the parts needed by modern weapons; you still need machine tools to finish the job. At the moment working parts will be limited to roughly what could be done by hand 100+ years ago (though much quicker of course). With the printing techniques currently used I don’t see the precision improving much.

    • Old Rockin' Dave says:

      The key word here is “currently”. The technology will improve, unless some intrusive way is found to hobble it.
      As for mass production by printer, that will come too – think of the custom cars that come off conventional assembly lines. A pistol with a grip that matches your hand? A shotgun made to your exact specifications? Easy enough, soon enough.
      Prices will come down while quality goes up.
      Even the most forward thinker may underestimate the development of new technology; think of the 19th Century mayor who declared that the telephone was so useful that he could foresee a day when every city would have one.

  7. Lb says:

    Did you really say it takes specialised knowledge to download movies? Australia logged a million downloads of game of thrones. It’s much easier than master days. So I hear. In short, I don’t think this part of your argument stacks up well.

  8. Nyar says:

    Now we just need a way to print our own weed too.

    • Phea says:

      Since it’s really, REALLY hard, (almost impossible), to grow the stuff, you should get started right away on that project, Nyar…

    • Old Rockin' Dave says:

      3D printing technology using living cells to form tissues is already here. Printing your own leaves starting with a cannabis cell culture should be possible before long. High times ahead indeed!

    • Max says:

      Just as states can outlaw growing and possessing weed, they can outlaw printing and possessing firearms.

  9. d brown says:

    When I was a kid I read ads for real, but unfireable Tommy guns. They were about 12 dollars I think, mail order. For less, the same people would sell you good good parts to make them firable. Nothing big happened. After JFK, buying guns mail order was stopped. There was no big difference. Complete printed guns, past zip guns, not state of the art and I don’t think they ever will be.

  10. Max says:

    Sales of pressure cookers are about to go through the roof, after their use in the Boston Marathon bombing.

    • tmac57 says:

      Hopefully,pun not intended?

      • Max says:

        Not this time. Should’ve said “about to take off.”
        By the way, when I google “sales take off” the first result is “Online gun sales take off.”

  11. Max says:

    It’s probably easier to print high-capacity magazines. As Cody Wilson says, “You can’t ban a box and a spring.”

    • tmac57 says:

      This guy strikes me as an ideologue without a moral compass,much like the ultra-Libertarians who see no need for any type of government or constraint of individual whims or desires.
      I expect to see his face splashed on the media some day while friends and relatives shake their heads and say ” He was such a young nice man.We never saw that he was capable of such a crime”.

      • Max says:

        He strikes me as a narcissist, similar to hackers like Julian Assange. I don’t think he’ll do anything crazy himself, but some day a “lone wolf” like James Holmes may use his designs to murder people.

      • Daniel says:

        Actually, most murders in the US, by a very wide margin, are committed by people that are, shall we say, in the Obama/Democratic party voting demographic. If you’re worried about being the victim of a violent crime, there is a 99.9999 percent chance that it will not be committed by a libertarian, even in a very loose sense of the word.

        The press’s overt efforts to blame the recent mass shootings on libertarians or tea partiers (the press made almost immediate “tea party” connections to James Holmes, the Boston Marathon bombing, Adam Lanza — or at least his mother — and Jared Loughner) would be hilarious if the events themselves weren’t so tragic. In fact, I am positive that if you gave a lot of these people the truth serum, most of them would admit that they WANT a mass shooting to occur and be committed by someone they’re ideologically opposed to. Mike Bloomberg has basically admitted that he wants to see as many mass shootings as possible so he can get the “sensible” gun regulations that he wants, i.e., criminalize the private ownership of firearms.

      • tmac57 says:

        Actually, most murders in the US, by a very wide margin, are committed by people that are, shall we say, in the Obama/Democratic party voting demographic. If you’re worried about being the victim of a violent crime, there is a 99.9999 percent chance that it will not be committed by a libertarian, even in a very loose sense of the word.

        If you are hinting at the stereotypical image (racial) of gang related violent types being part of the “Obama/Democratic party voting demographic” then I would first question whether gang members bother to vote at all,and second,shame on you for tarring half of the U.S. as being responsible for most violent crimes without any facts to back it up.I would think that most VOTERS on either side of the aisle tend to be civic minded,law abiding citizens.
        My comment was about ‘ultra’ Libertarianism, which I think crypto-anarchism could be considered to be a branch of. But in any case,it was his particular manner of behavior and expression of his ideology that,gave me pause that he might be someone to be concerned about.
        What is the source of your offensive comment about Bloomberg? Do you really believe that he “wants to see as many mass shootings as possible”?
        Where do you get your “99.9999% chance that Libertarians will not commit a violent crime” from? Are you invoking the ‘No True Scotsman’ fallacy here?

      • Brainmatters says:

        Thanks for the rebuttal tmac–you saved me the trouble and were more civil than I would have be enable to manage..

    • Phea says:

      “You can’t ban a box and a spring.”

      If they ever do, we’ll all be sleeping on waterbeds…

  12. d brown says:

    “You can’t ban a box and a spring.’ They did, then un- banned them.

  13. Ryan says:

    The lower reciever bit is also a bit off. As I understand (and I’m working off memory here) it the reciever is the main body of the gun, it houses all the machanical shooty bits and has to absorb most or all of the recoil forces (so the part must be strong or the gun will fail). Legally this is usually the regulated part of the fire-arm, as its for all intents and purposes the gun itself. Most guns have just the one reciever or frame.

    Certian fire arms have a multipart body. In this case the AR-15/M-16 series of rifles which have a 2 part reciever (so upper and lower). The upper reciever is technically speaking the gun portion of an AR-15. It houses most/all of the parts needed to fire it. Barrel, chamber, bolt, even much of the firing mechanism etc. And I’ve been told can be fired without the lower reciever attached. It also absorbs the vast bulk of the recoil force. The lower reciever basically just attaches the stock and houses the trigger mechanism and magazine catch. With much of the force absorbed by the upper, the lower reciever can be much less robust. But oddly the lower reciever is the portion of an AR-15 that gets a serial number and is controlled by law. And it represents a bit of a unique situation; the less integral, easier to make, less quality demanding part is the only part you can’t buy in a completely unregulated fashion. I remember there being a lot of controversy about it years ago, as it accounts for a portion of the AR-15’s popularity (particularly with gun smithing hobbyists).

    The plastics and cintered metals used in 3-d printing are and always will be significantly weaker/more prone to failure than the machined and stamped metals usually used to build guns. They just wont be able to contain the forces neccessary. Certianly not for a reciever, chamber or barrel. But with an AR-15 that doesn’t really matter, as you can easily and legally acquire all those bits from professional manufacturers. Without oversight. And the lower reciever can be quite easily built (or finished as noted from an 80% complete part) even with very simple tools. It doesn’t need the strength of stamped or machined metal. So that’s basically what makes its possible to print up a lower reciever for an AR-15. And whenever you hear talk of a lower reciever you’re likely hearing about the AR-15. Most of the “3-D printed gun” things flying about out there are really about 3-d printing an AR-15 lower reciever, and the issue is largely unique to the design.

    Sorry for any inaccuracies, as I haven’t looked into this in quite a while .