DIY Barrel Rifling with 3D Printed Help

[Jeff Rodriguez] has been busy testing a feasible DIY method for rifling a barrel and has found some success using salt water, a power supply, wire, and 3D printed parts to create the grooves of rifling without the need for any moving parts or cutting tools. Salt water flows between the barrel’s inside surface and a 3D-printed piece that holds wires in a precise pattern. A current flows between the barrel and the wires (which do not actually touch the inside of the barrel) and material is eroded away as a result. 10-15 minutes later there are some promising looking grooves in the test piece thanks to his DIY process.

Rifled barrels have been common since at least the 19th century (although it was certainly an intensive process) and it still remains a job best left to industrial settings; anyone who needs a barrel today normally just purchases a rifled barrel blank from a manufacturer. No one makes their own unless they want to for some reason, but that’s exactly where [Jeff] is coming from. The process looks messy, but [Jeff] has had a lot of space to experiment with a variety of different methods to get different results.

There isn’t a comprehensive place for [Jeff]’s collected results yet, but two image galleries showcase him moving from DIY rifling tests to using the concept to cut a chamber for a barrel. [Jeff] walks through his whole process in two longer videos, embedded below.

Low-tech DIY firearms often settle for smoothbore barrels, but not always. We’ve seen projects with homemade setups for rifling barrels but they involve repeatedly pulling cutting tools of some kind through the barrel.

[via TheFirearmBlog]

89 thoughts on “DIY Barrel Rifling with 3D Printed Help

  1. Holy crap. This is almost a holy grail for rifle manufacturing.

    The key is going to be keeping it low cost while maintaining the capability of creating a usable rifle barrel. I’m betting you don’t need sub-1/2MOA accuracy/precision, but you aren’t happy with a smoothbore.

    Looking forward to see how this continues.

    1. HAD,
      As a reader that has fat fingers I once again ask that something be done about either the dialogue to report a comment (option to cancel report comment) or the placement of the button. Maybe switch Reply and Report buttons?
      Yes, I fat fingered the report button again as I was scrolling down on my phone.

      1. The button doesn’t actually do anything unless several other unique users/IPs click it as well. The button stays because HaD gets more comments and page views every time someone comments about the report functionnot being where they would rather it be placed.

        I think they should move it for April Fool’s day, just to troll the commenters.

    2. I think it is interesting but not in any way a holy grail. A barrel isn’t exactly expensive and making a rifling machine (with more control over the pattern) isn’t hard nor expensive.

      1. I can make any part of a firearm at home, except for a decent quality rifled barrel. Further, I can do that without using any tooling that raises eyebrows.

        The ability to rifle a barrel at home is pretty high up on the list for the serious home build enthusiast who wants to do it because “It is there”.

      1. This is Electrochemical Machining, which isn’t too different from EDM in many respects, but is lower energy and is really just backwards electroplating. I think Ruger uses this for some of their revolvers now, too.

        1. I know Smith and Wesson uses either EDM or ECM to make their revolver barrels but I don’t know about Ruger. I think it’s also how the aftermarket barrel manufacturer EFK Firedragon does it too.

          In many ways these barrels are like the hammer forged polygonal barrels used by HK and Glock. While I can’t attest to the claims that they will last longer or offer better ballistics than a more standard barrel with true lands and grooves I can tell you that in my experience they are much easier to clean after a day at the range.Though I have heard they will foul up faster with lead if you use unjacketed bullets.

    3. I think if I were manufacturing at home I’d focus on shotguns. A sabot slug can be used to about 100 yards, which covers a lot of ground. Sure, rifling goes further but it’s hard to improve upon the simplicity of a smooth metal tube when you want to just get going.

    1. Presumably this is legal to make yourself (if you can own and operate a machine shop, you probably are level headed enough to own a gun that you can legally purchase in many jurisdictions for $500 anyway) but can anybody weigh in on the US legality of selling this? That part seems less clear and I am most certainly not an attorney.

          1. Wikipedia has Electroetching as being a metal etching process that involves the use of a solution of an electrolyte, an anode and a cathode. The metal piece to be etched is connected to the positive pole of a source of direct electric current. A piece of the same metal is connected to the negative pole of the direct current source and is called the cathode.

            It has EDM as where material is removed from the workpiece by a series of rapidly recurring current discharges between two electrodes, separated by a dielectric liquid and subject to an electric voltage. One of the electrodes is called the tool-electrode, or simply the “tool” or “electrode,” while the other is called the workpiece-electrode, or “workpiece.” The process depends upon the tool and workpiece not making actual contact.

            The article seems to indicate that the current flows between the barrel and the wires (which do not actually touch the inside of the barrel, which initially made me think it might be EDM) and material is eroded away as a result. I fully admit that I only have limited experience actually doing EDM so I am absolutely not clear all of the specific details and this unfamiliar process uses salt water, but EDM uses a very pure deionized water instead.

            Neat process, thanks.

      1. In the United States, (federally speaking) it is legal to make your own firearm. If you could buy legally it you can build it legally, excepting fully automatic, with no manufacturing licenses.

        It doesn’t need a serial number, or registration, but if it does not have one it is un-transferable (can’t sell it).

        The part the BATF cares about is the “receiver” or “frame”, that is the “firearm”. Everything else isn’t anything.
        There are a couple additional “firearms” “Destructive devices” are “firearms”. “firearm silencers” and “firearm mufflers” are also considered “firearms” in of themselves (and require a tax stamp)

        But, never trust a stranger on the internet when it comes to laws! This is just a ‘The More You Know’ sort of thing.

        1. You can make your own single shot, manually cocked multi-shot (single action), double action – where pulling the trigger simultaneously cocks and fires, or semi-auto – the trigger only fires it, the force of firing cocks it for the next shot, firearms in most US States. What you can’t do, per Federal law, is sell a firearm you have made unless you have a manufacturer’s license.

          If you want a perfectly legal rapid firing gun, build a Gatling. It’s not a “machine gun” because it does not use recoil or expanding gas from the gunpowder to ready it for the next shot. But don’t operate it with a motor, electric, air, hydraulic, water, wind power etc. That makes it a “machine gun”, somehow, despite the functional mechanics of it not changing one bit.

          There is a process by which you can build a new machine gun which is not an old one made before 1986 and registered before the cutoff date, but it’s complex and expensive and even if you follow all the rules the ATF may decide you aren’t and then your ass is in a sling.

          What’s quite popular is the 80% AR-15 lower receiver. That’s one that has 80% of the machining processes completed to make it a functional gun part. The ATF rule on it is that absolutely no part of the area where the trigger mechanism will be installed can be machined before you, the person without a gun manufacturing license who will be building an AR-15 based gun for his or her own use, takes possession of the part.

          Once *any* cutting is done on the trigger mechanism area, even a shallow drill hole, it becomes a “firearm” – nevermind that it would still be completely non-functional except for mounting other parts onto as an inert assembly. A manufacturer of cast aluminum 80% AR-15 lowers recently got into trouble with the ATF for having a narrow slot formed in the trigger mechanism area, to make the machining process easier. According to ATF the company was manufacturing firearms without a license.

          80%
          https://www.midwayusa.com/product/2228264558/ar-stoner-80-pct-lower-receiver-ar-15-aluminum

          Compare to the finished ones here
          http://www.tacticalmachining.com/100-receivers/ar15-lower-receivers.html

          See the open area above the trigger guard? That’s what the Ghost Gunner CNC machine and software are built to do. Mount an 80% lower into its jigs and run the G-code for each step, switching jigs and orientation as required. When done you have a 100% lower around which a complete firearm may be assembled.

          1. Not sure what you’re saying about Gatling guns is true. I’ve been told that “machine gun” covers anything that sends multiple projectiles downrange with a single trigger pull.

          2. a gatling doesn’t have a trigger, it has a hand-crank, and fires each round individually (just like a semi-auto where you pull the trigger multiple times)

            if you hooked an electric motor to the crank, it would then send multiple rounds downrange at one trigger pull (switch turning on) and would be classed as a machinegun

            I don’t know if he’s right about this, but his logic is consistant and it doesn’t conflict with your interpretation of the law.

            David Lang

          3. Actually, you are allowed to sell homemade firearms without any license, as long as you’re not “in the business” of selling firearms. So it really hinges on whether your intent, when making the firearm, was to sell it or not.

            Of course, this is open to interpretation by the judicial system, so if you end up making money selling your creations year after year, you may be “in the business”.

          4. it probably fits in with the definition of a gun dealer. If you only do a few, once in a long while, you may be Ok. But if you do enough of it to matter financially, you will probably be in trouble

            This is what some people refer to as ‘the gun show loophole’. The law still requires background checks and licenses for people at gun shows in the business of buying and selling guns, but if someone is there selling something else and buys/sells/swaps a gun, that doesn’t make them a dealer.

          5. Making or transferring both come down to intent.

            If you make with the intent to transfer you need a license to manufacture. If you transfer with the intent of running a business you need a license to transfer.

            Gatling guns are legal under the frozen person rule (not sure what the technical name is): if you were to freeze someone so they stopped moving it is a machine gun if it keeps firing and not a machine gun if it does not keep firing.

            One trigger attached to multiple sears can be considered a single shot for this purpose if they fire simultaneously. Gatling guns only shoot as long as you’re cranking. Attaching a power drill to a Gatling gun makes it a machine gun because it keeps cranking if you hold down the drill trigger. A trigger that releases the sear on squeeze *and* on release is also not a machine gun because if you did not move nothing would happen. I don’t know if anyone has gotten an intent letter from the ATF on single-trigger with multiple delayed sears – that would be interesting.

      2. Legally a barrel is just a piece a metal, it’s legally meaningless one it’s own, only with it it’s attached to a firearm does it gain any meaning, and only a little at that. The length and type or barrel, rifle or smoothbore, is a prime determining factor of the classes of firearms in US law.

    2. The likelihood that you’re going to be able to get rid of such a huge paper trail that would incriminate you anyways is very small. Just think about it this way. Everything you buy goes into a computer of some sorts. Every time you pay, even with cash, you are likely to be present where a camera will record your face–even if it is entering and exiting a store. If such a technology warrants an escalation in data processing during due process investigations, then trust me, some DA is going to find a way to make it work. Its a wonder it doesn’t already happen now. The only way to truly have no paper trail is to buy in places like flea markets and such, where you may be able to get a gun face-to-face, but not the type of equipment necessary to perform this. The juice is not worth the squeeze. Its easier to just buy an illegal gun, and its easier for a DA to rely on other sources of forensics like DNA and powder residue along with traditional police work.

      1. What is more likely, is that this will make the prohibition angle look sillier and sillier, because after all, if you can piss on a bunch of leaves in a bag, make charcoal from some willow branches, and get sulphur from a garden store, you can make gunpowder, and if you can buy iron pipe, etc, you can make a shotgun of sorts. You could probably 3d print a fairly comprehensive firearm using that technology, and countries with full prohibition are experiencing problems with smart criminals finding a way to manufacture firearms and sell them to criminals who won’t care that guns are illegal. If you can make a full machine shop from scrap aluminum and easy to find cold rolled steel and tool steel, you will never stop criminals from coming up with ways to acquire untraceable firearms. Better to put that money into other forensic technologies that make it foolish for anyone but a lawful gun owner to fire a weapon, and then only in self defense.

        1. Maybe, just maybe, this paranoia for absolute safety will lead the world towards 100% recycling of everything scrap!

          Or else, in a wicked turn and twist, everything will be made of materials which are designed to rot suddenly and fast after the expiration date … which will probably make any hacking we know and love today (except stable materials production, unless it is forbidden as ultimate sign of being up to no good) pointless :(

        2. Unfortunately for those who wish to be law abiding gun owners in some countries it’s just seen as easier to make guns illegal for all and that way if you have one it’s an easy automatic prison sentance. Because the only people with guns are criminals.

          And then do the same with knives.

          I don’t wish my hobby to result in a “holiday” of ten years or three years respectively from my family, because the risks out weigh the rewards.

          For some criminals in prison for gun or knife possession they clearly thought it was worth it and in some way I have pity for them that their lives are so screwed up/worthless that they were willing to take that risk of loosing their liberty for such a long time.

    3. Real life is not like the cop shows on TV. The matching of the bullet to a barrel was never used successfully to solve a crime. Thats why even states like MD finally quite requiring a shot bullet and wasting millions of taxpayer $.

        1. I’m not sure if it’s _never_ been successful, but I have seen studies showing it to be less effective than guessing, even in a controlled environment with a low number of choices to match to. I’m under the impression that it’s not very useful at all.

        2. MD was the last state to drop the requirement just last year or the year before (the years all run together anymore) so you can still find the data. Over a decade of having the program they only used it in around a half dozen cases and it didn’t affect the outcome of the investigation or trial on any of them.

      1. My understanding is that matching the bullet to a barrel is the sort of thing the police wouldn’t use to find a suspect, so much as to check if a gun found with somebody you’ve already caught is going to be useful evidence at trial. In the absence of a clear match (which one often can’t count on), you’re more likely to see something like, “The victim was shot with a 9 mm bullet. When we arrested so and so, he had this 9 mm gun in his car.” As Greenaum noted, a barrel swap that changes caliber is likely to be a bit more of a headache for cops than modifying the barrel to change marks on the bullet. Or the old standby of, you know, disposing of the murder weapon before the cops catch you with it.

    4. A gunsmith once told me that if you want to stump the forensics, just jam a rat-tail file into the muzzle and buy a new barrel. They’ll never get a good exemplar.

    5. I could see this potentially changing the rifling but it would be visible that something had been done to the existing barrel and would likely oversize the bore. You would probably wind up with the original rifling still evident and the secondary rifling just cutting through it.

      It is much easier to just buy a replacement barrel. Nearly every modern firearm can change out the barrel without too much trouble and replacements are usually easy to find. Some people like different types of rifling for different scenarios; for example a person may use the factory hammer forged barrel in their Glock 17 when carrying it for defense but if they decide to use the same gun in a competition they might change to a button rifled match grade barrel.

      Heck some folks even get different caliber barrels and swap them so they can have two guns in one; like how most 357 Sig and .40 S&W pistols have interchangeable springs and magazines so you can use either caliber in the same firearm with just a barrel change.

      I always thought it was kind of funny that most non gun folks never really seem to give that much; at least I’ve never seen interchangeable barrels come up in a show like CSI or NCIS. The only part you can reasonably be sure isn’t easily altered when doing ballistic fingerprinting is the bolt face so the base of the casing is where real data can come from, one would have to machine the slide to alter this. The firing pin, barrel, and extractor, basically everything else that come in contact with the casings or bullet, can all be changed out in a couple of minutes.

  2. > “Rifled barrels have been common since at least the nineteenth century…”

    Make that since American colonial times. Two summers ago, I visited Martin’s Station, a restored colonial outpost in SW Virginia, and watched a re-enactor demonstrate how rifles were hand-made in the mid-eighteenth century.

    1. is that the place that had a large wooden contraption with a carved wooden twist in the middle that caused the tool to rotate as it was pulled thru a “mountain man” length barrel? saw something like that years ago on PBS, guy took the forged barrel stock, cut the rifling with this very large wooden tool, proofed the barrel “old school” by overcharging with powder and using a fuse thru the touch hole, then went into the woodworking for the stock and some of the metalwork for pan, spring, trigger and the rest.

    2. actually, rifled barrels have existed for a long time, but they weren’t common before the Civil War due to the reloading time. reloading a black-powder muzzle loader was bad enough, but having to hammer the bullet down the barrel made it something used very rarely, and never in a situation where a miss could put your life at risk.

      the minie ball changed this (followed almost immediately by breechloaders)

        1. Zirconia? Why anybody would want a metal free gun is beyond me, metals are near ideal for the critical parts. Composite sure, CFRP around a high-strength steel barrel with a hard ceramic coating inside could have many advantages (and some disadvantages).

      1. i think the fastest way of machining ceramics today is ultrasonic machining, think milling machines with vibration instead of cutting, they can machine zirconium and are usually how dental zirconium crowns are made.

  3. Isn’t etching going to have a different result than cutting? Etching is going to follow the crystal structure and would tend to enlarge any faults in the steel. Cutting might work harden the steel.

  4. About 15 years ago I toured the Smith & Wesson factory in Springfield MA arranged through an organization I belong to. This is pretty much the process that they described as using to rifle all of the handgun barrels they made there. The guy giving the tour described it as a sort of “reverse electroplating” process. Said it took about 7 minutes to rifle a barrel and they were done in racks with many barrels on each.

    1. I highly doubt that they were talking about barrels. Production barrels (major manufacturers) are 100% either button rifled or forged, with some custom barrels being broached or single point cut. No one is using EDM let alone etching on production barrels, period.

      EDM, which is likely what they were talking about, is used extensively in the industry but usually for operations where traditional milling is not feasible.

        1. You are correct, in that case they were all handgun barrels that they were referring to, and at the time we were there it was mostly revolvers on the production lines we saw. They were specifically not doing EDM and stated as much when someone in the group asked. It was as the guide described “like reverse electroplating” or what most call electro-chemical machining. Very different than EDM. No idea how they were doing long guns.

      1. change your D to a C and ask S&W…theyve been cutting more and more barrels this way since the early 90s using surftran machines. Often referred to as electrolytic rifling, cutting barrels with electrochemical machining is quite effective and employed by more than one manufacturer.

  5. I see one big issue with this method. Etching actually pits the metal and the last thing you want in the groves is any pitting. Once however you make the groves you could then draw a specially shaped cutting tool down to scrape the last of the surface clean and polish it.
    A process i saw some year back used several die like tools that would scrape the spiral. each die was slightly larger than the next and was drawn down the tube using a threaded rod. its a lot faster than etching that’s for sure.

    1. Meh, I think there are more important factors at play than some pitting in the grooves. Those will get filled in pretty quickly with lead or copper fouling, if it even mattered in the first place.

    2. My own limited experience with chem milling has been that as long as you’re not going very deep, you can get a very nice matte surface on your etches, with no visible pitting. I’ve only done this on stainless steel flatware, so I don’t even know what alloy it was. But I’ve also seen chem milled cover plates on electronic instruments, with both perforations and component marking (around .25 mm deep) in brass that was also very smooth.

      It seems to me that with good pre-cleaning you could get a better finish than is generally achieved with spiral cutting jigs.

  6. That is some seriously archaic looking software. I guess I’ve just never like the concept of purely parametric modeling, I’ts just so slow and awkward. The insistence on parametric tools has kept me, as a Blender user, out of the CAD field because everyone insists on their own flavor of early 2000’s modeling program. I get solidworks or inventor, but RhinoCAD seriously?

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