3D printing of functional plastic guns
Well The Media is now worried about the possibilities of using a 3D printer such as a REP RAP or MAKERBOT to print out a functional, aka, shootable firearm. It has been pointed out that ABS is just not strong enough to contain the presssures of a .22 Long Rifle cartridge. The strongest material in used in 3D printing is UTMEL which is less than half the strength needed to contain a .22 Long Rifle (around 22,00 PSI). Never the less there are companies that are stating they will be able to print a fireable, printed Gun, very soon.
They are working with the .38 special Cartridge and the .45 Long Colt cartridges. Both of these turn of the Century cartridges have low working pressures in the area of 15,700 PSI. At this they are still 50% higher than the cureent 3D material strenth of around 10,000PSI. The challenge of “printing a GUN” are going to be enormous. For Safety Firearms “Barrels” are built to withstand much higher pressures than will be seen in normal use. For instance the modern .38 special barrel will not fail under .357 Magnum pressures (35,700 PSI). There are some very light .38′s out there that will fail after repeated firings of magnum loads. The best you could do is design a “ONE SHOT” “fire and toss” handgun with current 3D materials. It would have to be a smooth bore affair with only very short range accuracy. If you get into a gun fight inside a phone booth type accuracy.
The “MEDIA” is worried that a “printed” gun will be able to fool the metal detectors at the airports. With current technology that is just not or just barely possible. Almost any design is going to need at least some metal parts to operate reliably. springs are just a case in point. I have seen some of the stuff that comes from a 3D printer right now. I just think a high tension spring is not really possible at this time. This debate was mainline to the attemps to ban the Glock pistol when it first hit the market. If you own or have held a Glock pistole you know the is a significant amount of metal in it. To ease the fears of the unknowledgeable there was metal (beryllium?) powder added to the plastic to make it stand out on xrays. The fact is that there was metal in the frame already. There were the Slide rail mounts and a couple of other pieces in there.
There are viable solutions to the problems of manufacturing a Firearm “part” in a 3D printer. Such a part has already been made. An AR-15 lower receiver has been produced. In an AR-15 the lower receiver is the licensed part or considered a “gun”. This part does not have to contain the firing pressures. It is the carrier for the hammer, trigger, magazine well and a couple of dozen parts. The upper receiver mounts the Barrel, Bolt and bolt carrier. The Barrel and Bolt are the two main pieces of an AR-15 that contain the pressure at the firing of the rifle. But an AR-15 upper receiver takes a real beating as the bolt and carrier cycle in semi-automatic fire. An ABS upper receiver will fail in relatively short order. Of course this does not matter in a “THROWAWAY” gun. There is also the option of printing around a metal tube or metal stampings to reinforce the structure at key points. But how many people do you know, that you would trust, if they handed you a “printed gun” and asked you to fire it.
There are going to be a few technical challenges that will nbeed to be met before a “Plastic Gun” can be downloaded and printed. first of all most of the 3D printers I have seen work in only 3 axis of motion X (depth),Y (width) and Z (height). To properly build a strong barrel you would have to add the fourth axis which is rotation. You wopuld have to have a mandrel that can be heated to the working temperature and maintained. It would have to have sensors to allow it to be maintained at the precise temperature. Does not sound to daunting until you add in the that it must be slightly below caliber. (or calibre) I t would be very hard to work all of this into a .38 caliber (.357 jacketed or .358 in lead)) diameter mandrel. You also have to allow some space for the teflon or other tape or cover that will allow the work to be released at the completion of the “printing” process. Larger Calibers such as the .45 Long Colt (.452 in lead and .451 in jacketed) will make this a little easier. Larger diameters of tubing are not as strong as smaller diameters. So too large and you lose too much strength and smaller you have to invest more to design a working Barrel mandrel. As for adding Rifling to stabilize the projectile of choice. Not going to work. The first shot will end up with a very rough”smoothbore” as the rifling will be gone. There are ways to make these technical problems work out, but overall you will be working with a firearm that is, at this time in the technology, Well, Dangerous.
There is that lure of being able to download a design and print it out. That is why 3D printing is going to grow. As prices come down and the sophistication goes up more things will be able to be produced at home. There is already designer shoes and toys and such out there in the design libraries. And there is a big push for DLA for such designs so designers can cash in on the “print at home” market. Cut out the manufacturing middle men. But when it comes to designing a firearm there is just too much potential for disaster. Either a Criminal uses the technology to build throw-away crime guns or a person decides to substitute the working material to save money or change the design. In either case someone is going to get hurt, or killed.
Ok so a little more investigation into the Printable Gun. Printableguns.com is stating that their goals are to make the CAD files available to anyone who wishes to download them, at no cost. They state that their ultimate goal is to have Rep Rap style printers able to print a firearm. I saw one obvious problem in their video right off the bat. The file type that they are using for their project is only readable under some very expensive software. AutoCAD is one of them. At $1399 for their light version and you have to call for a quote of the full version. TurboCAd is cheaper and probably will work, but is still $300+. Also their belief that it is a good idea to make a printable gun available to the world, if they have a 3D printer. Very few LEGAL gun owners are going to choose to print a “gun”. Legitimate firearms owners follow the Law when they purchase a firearm. Building a firearm is LEGAL in all states though the rules vary from state to state. Even in the Peoples Republic of California (PRC my name for it!) it is actually legal to manufacture a firearm (Rifle) for your “own” use. The legality of producing a handgun in California is very suspect. All handguns in California require registration. To register a firearm you have to have proof of its manufacture through documentation. There is no documentation, from a manufacturer, (you do not have a MANUFACTURERS License) so you cannot produce the documentation. A rifle that meets California rules as to barrel length and overall length, which does not conform to the California regulations for an assault weapon, does not have to be registered if you manufacture it for your own use. You are advised to stamp your name and address onto the firearm. I would also stamp its caliber. If it is semi-automatic and it “could” accept a high capacity magazine (more than 10 rounds in California) you would be advised to choose a magazine type that there are no high capacity magazines available. Also manufacturing a magazine over 10 rounds is an offense in California. One of the Defense Distributed examples is an AR15 lower receiver. They state you can readily buy every part except the lower which is the registerable part. And they were very careful to add that they built an AR15 lower not a M16 lower. If you have enough experience to use a Rep Rap or Makerbot, you can change an AR15 lower into a M16 lower. Of course there are other differences in parts such as the bolt carrier assembly and various sears and springs needed to complet a M16 lower. I think overall that expecting an individual to print a firearm that will be safe to use is full of false assumptions. Assumption #1; that all 3D printers will be able to reproduce similar exacting tolerances. Assumption #2; that all material being fed to the printers is created equal. Assumption #3 that the users know how to adjust their printers too those very exacting tolerances. Assumption #4; Quality control, That the person printing a firearm understands firearms design and materials well enough to reject a flawed production piece. They will very neatly be protected from liablilty, as they did not produce the firearm. That is one of the reasons that Firearms are so expensive, Insurance. Manufacturers have had to defend themselves against cases where a criminal caused the death or injury of a person/s and trhe Lawyers look for the “Deep” pockets, The Manufacturer. This is not exclusive to Firearms either. Automobile companies are constantly being sued for everyday accidents. But you produce your own “Gun” and it explodes in your face, who do you sue. My biggest problem with the “Open Source” Firearm is that not everyone who will use these designs will use them lawfully. Not everyone will use them safely. And by not using them lawfully or safely they will push the lawmakers to further assault the rights of our gun ownership.
To take away some of the heat that is always present, when comments about firearms are at issue. This company comes out with an Automobile. It can be printed in modules that can be assembled into a working car. You build the car. But you cannot afford to put brake lights in it, or headlights, or turn signals, or airbags, or seatbelts, or in general any of the safety equipment that is required for all automobiles. But you have been told that the vehicle is “SAFE”. Are you responsible for the death or injury of occupants in your car or the one that hit you because you had no “Safety” equipment? Yes you are! And you will be pulled over and stopped, hopefully before that accident happens.
I think I should add: I am a proponent for the Second Ammendment. I believe law abiding people should have the right to own firearms. I believe in the right to defend yourself. I believe it is your right to build a Firearm as long as it is within U.S. Laws. We do have to defend this right. Responsible Firearms ownership is how we defend those rights!
More to add later
It is now later!
Defense Distributed has built a 3D printed gun that works. The hand grip is an AR15 grip unit. The receiver, pins, trigger springs and barrel/chamber are all printed. The firing pin is constructed from a common metal nail. The Barrel/chamber can only be used once and then is discarded. It is called the “Liberator”, named after a pistol that was dropped to fighters in WW2. The barrel/chambers are loaded before hand and carried as extras. when one is fired it can be replaced with the next one. It is chambered in .380ACP also known as .380auto. This cartridge is pretty efficient.
There are a couple of things that you should understand before you try to recreate this feat on your Rep Rap or Makerbot. The printer that was used for the Liberator was an upper end printer that is around $50,000. The barrel units are printed around a special heated mandrel and then are chemically treated to smooth the barrel for lower friction and to make the assembly more robust. Also some of these barrel/chambers have exploded destroying the “gun”. The plans for printing these was posted online, but ordered to be removed by the state department.
For those that are worried about plastic guns being printed out by the thousands and being used by all sorts of criminals, well not just yet. The firearm takes a day and some change to print, each! The material to print them is not the sort used by the lower end 3D printers. So I think we have a little time before these are being seen all over the streets of America!