In The Line of Fire

Messing with the Left is the political equivalent of beating up your little sister. It’s not even sporting but it’s still interesting to see each new variation on the old familiar theme. The Right has it down to a science; is the Left never going to catch on?


If you set out to gin up a bogus controversy that would maximally distract the people on the Left while twisting the indignation of the Second Amendment crowd to a fever pitch, you just can’t beat 3-D printed guns.  No aspect of the controversy makes sense, yet the forces of darkness have millions of people fretting about it instead of worrying about things like why the EPA is being gutted or why it’s America’s new policy to drive Turkey out of NATO and into the loving embrace of Vladimir Putin.


It’s clever, really. Draw a Venn diagram of people who use machine tools, people who understand 3-D printing, people who know a lot about guns and gunsmithing, and people who aren’t already on the Right. The gun-printing activists know that if you aren’t in that minute triangular intersection (technically it’s a Reuleaux polygon but let’s not quibble) they can say anything they want and you won’t be in a position to question it.

The truth is, 3-D printing adds nothing to the problems around gun violence or gun control. The entire controversy is literally designed to be a place for Libertarian and Right-wing resentment to crystallize into a few more votes.


Most people’s anxieties about printing guns boil down to some version of these three things.

  1. You can print plastic weapons that can pass through metal detectors.
  2. People can print ghost-guns that are unknown to the government.
  3. Crazy people and criminals can print up weapons without that pesky background check.

Assassinating Presidents and Hijacking Planes

The first obvious silly thing is that 3-D printing doesn’t magically generate things you couldn’t make by hand if there were no 3-D printers. In many cases, it’s more trouble to print something than it is to make it the old-fashioned way.

4167PGT0H9L._SY445_If you need a gun that’s invisible to metal detectors and don’t know where to start, just order the Clint Eastwood shoot-em-up “In The Line of Fire” from Hulu. This 1993 film featured John Malkovich as a would-be assassin who has hand-made a plastic gun that won’t show up on a metal detector. It’s super simple—there’s a picture above. You could make one just like it yourself in an afternoon even without a printer, based entirely on what you see in the film. It’s just a plastic zip gun. It’s not exotic tech; so many kids made zip guns in the 1950’s and 60’s that there used to be public service announcements telling kids not to make zip guns. They had the same sort of ads warning you about playing with blasting caps (which were awesome, by the way.) It was fun to be a kid back then!

I’m not sure who would win a John Henry style assassin-gun-building competition between a person and a 3-D printer, but I’m pretty sure John Henry would get at least as good a product by hand with a lot less equipment and know-how.  Definitely no printer required.

Ghost Guns

A Malkovich-style zip gun is easy to make but making a respectable rifle or shotgun isn’t all that hard either. A generation or two ago, making a musket, shotgun or even a rifle was something that talented high school kids did under supervision in shop class. I just Googled “gunsmith lathe” and there were a dozen manufacturers listed on just the first page of results. Any of them would be pleased to ship everything you need to make a high-quality weapon to your door, no questions asked. YouTube is full of people who’d love to show you how it’s done.

I’m sure your dad would have been impressed back in the 1950’s but when the zombie apocalypse comes, a shop-made .22 is not what you will want to sling over your shoulder. It’s not a real gun anymore unless it’s a semi-automatic, but even without a 3-D printer, it’s not that hard to make a real gun. In practice, it’s a matter of semantics more than gunsmithing.

America’s Favorite Gun

To keep it concrete, let’s talk about the AR-15. In case you’ve been living on another planet for the last decade or so, the AR-15 is America’s favorite gun, the archetypal assault rifle. (We could get all pedantic about the phrase “assault rifle” but you know what I mean.)


The AR-15 is affectionately called “Barbie for Men” because it’s all about accessories. You can trick them out in a hundred ways—long barrels, short barrels, various chambering, all kinds of stocks, clips, scopes, sights, materials, finish… there’s no end to it.  (The “men” thing is a sexist anachronism, of course. Lots of women shoot them. Adam Lanza borrowed one of his mom’s.)

I’m not wandering here—the fact that so many of the parts are swappable is important. Read on.

What Does Printing Even Mean?

You can’t really print a high-quality weapon in the way that most people picture the process. There is no technology on earth (yet) that will result in an AR-15 popping into the delivery tray like a can of Coke out of a soda machine. That’s not what they mean.

If you look at the diagram below, you’ll see a ton of parts, but legally speaking, one of them is very special. It’s the big part at the bottom, just to the right of the center line. It’s marked “lower receiver.”

This one part is special, because of all the pieces, this single part all by itself is legally a firearm. The lower receiver is to the gun what the chassis is to your car. It’s a one-piece aluminum casting with some holes and slots machined into it, and everything else that’s part of the gun either directly or indirectly attaches to it.

As gun-parts go, the lower receiver is a dumb hunk of metal, but no other part has this property. Even if you put the entire rest of the gun in a box, if the lower receiver isn’t there, it’s not a gun (at least to the Feds) and conversely, if you throw everything but the receiver into the ocean, the receiver all by itself is a gun. To buy that one part, you need whatever rigamarole you go through to buy a working gun.  The rest of the parts are just over the counter hardware. You don’t even have to show ID to buy any or all, even if you buy them all at once.

And yes, it is possible to print a lower receiver. You could definitely print a decent one on a $200K metal-capable 3-D printer, but you could probably get a working one on a desktop machine that prints plastic.  It’s questionable whether the one you make on your desktop would hold up when you fired the gun, but you could do it and if it failed, the gun would be broken but you wouldn’t get your hand blown off or anything like that.

So if you’re talking about printing what the law calls an AR-15, yes, you can definitely do it but we’ll see below that it’s a fool’s errand.

Can You Print an AR-15 That Actually Shoots?

The MakerBot sitting on my desk cost (someone else) a couple of thousand bucks but itar15.jpg only prints plastic. As I said, you might be able to print a usable lower receiver on it, but one of the most obvious problems with using it to print a working gun is that a lot of the parts of a real gun have to be metal to withstand the heat, pressure, and friction associated with accelerating bullets to as much as 3300 feet per second.

A printer capable of printing the printable metal parts for an AR-15 would cost about $200K and you’d need considerable expertise just to set it up and make it work. The caveat is that an automatic or semi-automatic weapon is not made of just one material. There are several kinds of steel, plus aluminum or magnesium, plastic, and rubber just in the gun proper.  To print all the printable parts you need more than one kind of printer.

Even if you managed to print all the printable parts, you would not have a working gun. You would also need machine tools and considerable expertise to finish them. A semi-automatic rifle is a precision device. Pistons and tubes need to be finished to exacting tolerances, holes must be bored and threaded precisely; practically every finished surface that contacts another surface would have to be machined to tight tolerances after printing.

I said printable. Printing the barrel, which is the most important component, probably isn’t possible with any current technology. You could print the cylindrical blank, but why would you? The blank is just a steel bar you could buy.  Printing might reduce the amount of lathe work on the outside, but the hard parts are the boring, rifling and heat-treating, and none of those things are printing operations. There are also numerous other parts that aren’t printable at all, such as springs, o-rings, gaskets, etc.

So no, while you can print that one part the Feds arbitrarily selected to constitute a firearm, you can’t print anything close to an entire AR-15 (or any other semi-automatic weapon) and you still have a ton of sophisticated machining to do on the printed parts.

Printing is a Red Herring Anyway


Notice that the receiver on the right is marked “Firearm” while the one on the left is marked “Not a firearm” despite what I said above about the receiver being what legally makes it a gun. That’s because the one on the left is nominally just a casting for hobbyist gunsmiths to machine into a receiver. It might look almost exactly like the one on the right, but until it has a few more grams of metal machined off, legally, it’s just a hunk of aluminum (at least in the eyes of the Feds—state law can be pickier.)

It’s hard to know what’s going on in the heads of the regulators. There seems to be an element of wink-wink. The “blank” looks almost like a finished receiver, and most of the hard parts of the machining are all done for you. For instance, it would take a significant amount of skill to set up a lathe to bore and thread that big ring on the upper left (where the stock screws in) so it’s conveniently done for you. The basic shape of the whole part is also milled in advance to make it easy to locate the holes that you have to machine. (It’s hard to do that if you don’t have known reference surfaces.) In practice, turning the casting into a working receiver doesn’t even require a lathe or mill because the same manufacturers will sell you a “jig” (i.e., a tool guide) that will let you do the whole thing on a drill press. (You can get one for fifty bucks on Craig’s List.)

I’m no heavy-duty machinist or foundry guy, but I have a hobbyist level lathe and mill in the basement and a homemade furnace out by the garage that can melt aluminum. I’m pretty sure that even with my modest skills, I could make a usable receiver from scratch out of melted-down beer cans in much less time than it would take to drink enough beer to get the cans. There’s a YouTube out there of a guy doing exactly that.

The thing is, I wouldn’t. The blanks are so amazingly cheap that it wouldn’t be worth making one except for the bragging rights. The one above sells for $69.  That’s less than half the cost of the required beer and, it’s already cast and mostly machined. Here’s a link to one supplier of such blanks.

Ghost Gun

As soon as you bore those holes, you have the only problematic piece of what is called a  “ghost gun.”  It’s a legal gun with no serial numbers. Just toddle over to the big-box sporting goods store and pick up the rest of the parts. You don’t even need ID. The rest of your AR-15 you can pay for in the self-checkout line. No kidding.

If that’s too expensive for you, so many people customize AR-15’s that you can probably pick up most of the parts from hobbyists who’ve swapped something special into their gun.

If you’re both cheap and in a hurry, ask a friend to buy a $600 AR-15 legally and let him or her keep the receiver and sell you the rest for $600. It’s perfectly legal and your friend comes out of it with a free receiver that he can turn back into a working gun using the same used parts you were too impatient to hunt down yourself.  

If all that swap-meet stuff is too much of a hassle for you, there are “80% receiver” manufacturers who will sell you the blank plus the entire rest of the gun in the same box. You just machine those holes, assemble it, and you’re ready to shoot zombies like a pro with your legal, unregistered, un-serial-numbered, firearm. It would take several hundred beer cans to make a receiver from scratch, but “making” a gun this way I’d estimate as a four to six can job. One long evening.


I’m not even going to discuss criminals, because why would they need to print a gun? They’re criminals—they can just steal one or buy one from another criminal. That’s the point of being a criminal.

That leaves just the crazies. This is another Venn diagram situation. We’re talking about just the crazies in that inner triangle who are (a) focused enough to learn about 3-D printing technology (b) together enough to assemble the awesome kit necessary to print a decent gun and do all the other machining (c) rich enough (d) smart enough (e) stupid enough to try to solve the problem by making a gun instead of just asking that guy at the bar to sell you the one his cousin left in his garage when he got violated back to jail.

That’s a pretty select group. There might not even be one such person in the world and if there is one, there’s a good chance that he or she is the kind you can keep occupied in the basement for the next several years trying to figure out how to print a gun.  So it’s hard to see this one as an issue either.

We Have to Stop Falling For It

A real 3-D printed gun would be a great conversation piece, but of the countless ways to get your hands on a working rifle, 3-D printing is in a league of its own in terms of expense and difficulty.

We all have to stop falling for this trick. They pick some niche liberal issue or they just make up a new one, then get us to do the hard work of alienating yet another segment of the public. Printed guns, transgender bathroom use, Chrismass creches, fancy pronouns, statues of 200-year-old dead white guys; we bite every single time and come off looking ridiculous, contemptuous or threatening to yet another slice of America.

We have a ton of real issues to worry about, not least of which is winning the 2018 midterms. Nobody is going to the polls to make sure we don’t have downloadable gun plans, but plenty of people will vote Republican on that single issue. It’s time to stop reacting to silliness and get the vote out on some real issues. C’mon liberals. Let’s do this thing.


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