Congratulations you just printed your first gun, it’s just a shame you can’t get your hands on any bullets. You’ll need a gun licence to legally buy bullets in the UK and many other countries. That or you’ll have to ‘know a guy’ that can get them for you because you certainly can’t print bullets.
2) One hit wonder.
You might have noticed that the current design of the “Liberator” from Defense Distributed features several interchangeable barrels. The barrels are also noticeably stubby and chunky, this is to deal with the massive hoop stress encountered in the barrel as the bullet is fired. After a single shot is fired, the barrel being made of plastic and having just had a hot piece of much harder metal dragged through it is often ruined and cannot be reused. Any rifling present in the barrel would have certainly been flattened by the first shot reducing the accuracy of further shots.
3) Are you feeling lucky punk?
Did he fire six shots or only five? Well the bank robber reaching for the shotgun would feel very lucky indeed as Dirty Harry posed him this question. Both the “Liberator” hand gun and “Grizzly” rifle only store a single round and have no reloadable magazine. Shots must be manually placed into the breech before every shot. In terms of multiple shot weapons the only thing that comes close is the lower receiver printed for the AR-15. I don’t class this as 3D printed gun as it was effectively a normal rifle with a single more minor piece replaced. It failed after firing as little as half a clip during initial testing. After some tweaking they managed to get around 600 rounds fired, but for an automatic weapon this is less than 3 minutes of fire. In order to change the lower receiver the gun would need to be disassembled in a process much more involved than simply changing a magazine. A real automatic rifle is capable of firing millions of rounds in its lifetime and tens of thousands of rounds in between service intervals.
What is a lower reciever? It’s effectively a large bracket that joins the handle or butt of a gun to the barrel, magazine and firing mechanism. Often they hold the trigger and safety, but these are relatively simple leavers as oppose to the complicated mechanisms required to produce an automatic rifle You can see why they chose to print this part first as its one of the simplest with no real moving parts and little real load to carry. You can also see why many of the guns available are only capable of firing one shot at a time.
It’s cheaper to go out onto the streets and legally, semi legally (forged paperwork, bribery) or even completely illegally obtain a back alley gun than it is to print one yourself. Even the cheapest home 3D desktop printers come in at around just shy of £900. It’s worth bearing in mind this is very much at the low end of the scale, industry quality 3D printers produce much higher quality parts but also cost 10 times as much.
5) Heavy is good, heavy is reliable.
We all know the famous line from Guy Ritchie’s gankster extravaganza Snatch. Boris the blade explains to us how reliable the guns he sells are, “Even if it doesn’t work you can always hit him with it”. Several tests of the Liberator or lower receiver printed for the AR-15 ended in catastrophic failure of the part. There’s been a reason for many years that major gun companies don’t make guns out of plastic, its hard to design for long life with such high repetitive shock loading.
6) Excuse me, Mr President, would you mind just stepping 3 inches to the left and about 20ft closer?
Well unless you’re within a few meters of your target, again, you’d be better off clobbering them over the head with your 3D printed gun. Extremely straight barrels with spirals of metal inside called rifles cause the bullet to spin improving accuracy, in plastic these are simply to soft to grip a metal bullet properly and wouldn’t survive many shots. Range is mostly likely affected by the plastic barrel over deforming during firing allowing the hot gasses behind the bullet to escape past it. The Walther PPK that James Bond famously carries is still an effective weapon at 25 metres or more.
7) Right children, as you can see the 3D printer is now connected to my laptop, I’ll just open the gun file in word and press print.
In order to design a part for printing it must first be drawn on a 3D drawing package, to produce something of any quality this is a process which takes knowledge of engineering and 3D printing as well as skill to operate the software. While finished .stl files are available for direct download you still need to tweak these files to suit your particular type of 3D printer. Material type, resolutions, feed rates, laser power, heat up, cool down times all depending on the printer you are using. It’s not beyond the realms of the average man but it’s not just a case of pressing the big red “Print Gun” button.
8) Over complication
At the farthest realms of extraction all a gun is, is a bullet in a tube, waiting to be hit very hard in the back with a sharp bit of metal. This is effectively the simple design that most 3D printed guns follow. But why 3D print one when prisoners of war, inmates and secret agents have all been known to make rudimentary guns from scraps of metal and odds and sods. Oddly enough you don’t see many of these DIY copper pipe guns being confiscated or used to hold up banks.
9) I’ve got the printer working and I’ve managed to find some bullets! I just can’t wait to get my hands on that bloody paperboy!
Hold your horses there, just because you’ve printed the gun doesn’t mean you can pick it up and settle your scores with the paperboy straight away. You’ve got at least an hour of cleaning and sanding to fettle the pieces together. Powder based printed process require the removal of excess powder from hollow spaces within the part and other methods such as fuse deposition modelling often have quite a rough surface finish. On the whole resolutions of around 0.1mm are achievable but overall tolerances can be difficult to achieve meaning you might have to file down the odd spot to get your gun to fit together and work smoothly. Post processing often gets overlooked when it comes to 3D printers.
10) But 3D printed guns don’t show up on metal detectors!
Neither does one made out of wood, which I also believe is entirely possible. If you don’t believe you could make a gun from wood, what about carbon or glass fibre? The only snag is you need a metal firing pin. This is however about the size of a nail and is already an irreplaceable part of any 3D printed gun.
Processes for metallic 3D printing do exist in the form of metallic powder laser sintering and are already quite widely developed however at an industrial or research level. The cost of these machines are again in the tens of thousands and no home or desktop variants exist. They also often have more steps in the manufacture process such as furnace sintering.
What’s really scary is the classic media spin doctoring and scare mongering around 3D printed weaponry. (It’s funny to say weaponry here as actually it’s all about guns, a 3D printed crossbow would also be quite feasible, just as deadly and actually legal to own in the UK!)
The public needs to ensure that this minor issue doesn’t dictate future legislation on the 3D printer industry and market. There is a rough legal road ahead of 3D printers as copyright claims and patent infringements suits become increasingly debated, don’t let large corporations grease the wheels and help the governments use ‘the 3D printed gun’ argument to restrict the free flow of information and plans for what is set to be the next industrial age.