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Mark Serbu, mastermind behind the Serbu Super Shorty and other oddball firearms, has a new design specifically intended to clog gun buybacks and allow people to actually turn a profit off of these events.

The GB-22 is a single shot handgun comprised of about four components. Intended to be manufactured by someone in their basement, the design requires only a hacksaw and drill to turn a length of bar stock into a functioning firearm. Shown in the video are some CNC machined examples made by Mark Serbu, but no CNC is required.

While it’s interesting to think that the gun can be produced for far less than the typical reward rate for handing in your heater at a gun buyback, in reality the time and effort required to construct such a gun is still probably prohibitive for those thinking about cashing in on this possible goldmine.

Particularly notable is that this firearm is basically identical to Cody Wilson’s Liberator handgun which caused such a kerfuffle with the Department of State over ITAR regulations. The only difference between the two is that Cody Wilson’s Liberator is 3D printed, while Serbu’s creation is crafted using “traditional” methods. I’d be interested to see what the Department of State has to say about this if he decides to publish the schematics and instructions online.

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  1. Seems like a lot of work when a piece of pipe banded to a 2X4 with some strategic markings will get you one of those “buyback” gift cards or cash just as well.

    • Safer that way too. I know these events are supposed to be “no questions asked”, but a smoothbore pistol is not something you want to be caught with. Make your “shotgun” a legal length and avoid walking around with an NFA charge waiting to happen.

      • Rifling is pretty easy to do, does the atf say the groves have to be a certain depth? How bout twist rate? .5 × 48 is damn near a straight line, rifeling don’t have to all that effective, just has to be there.

      • I think that a handgun designed to fire shotshells would be considered an (any other weapon) with a $5 transfer fee. If this is designed to fire .22 long rifle shells you might be good.

        • But you’re not transferring it, you’re making it, and that’s a $200 stamp even if it’s an AOW. Regardless, you still have to do the whole NFA process with a Form 1 and receive approval to build it. Without that, it’s a 10-year Federal prison kind of a violation…

          I’d file some “rifling” in there, if I were me.

        • The barrel is so short and the steel is probably soft enough that you could file up a broach out of O-1 drill rod and push it through with a press or (even) a hammer. Boom, rifling.

          .22LR’s are usually twisting 1 in 16″.

        • The ATF ruling is that open-bolt guns are “readily-convertible”…to full-auto and thus *are* full-auto as far as they’re concerned.

          In an unusual display of logic and sanity, I guess the ATF considers single-shot rifles and pistols to not be readily convertible even if they are open-bolt.

  2. It’s pretty telling that buybacks are increasingly refusing pipe guns, zip guns and other makeshift functional firearms.
    I guess a photo of some hardware laying on a table (even if it adds up to 100 guns) is not as PR friendly as a photo of a single old production black rifle turned in by a widow.

    Or maybe they just don’t want to scare the plebes by showing them a functional firearm can be made at home with no tools for less than $20?

    I recommend anyone with anti friends or acquaintances offer them a field trip to the local hardware store and buy the parts, assemble the gun and fire it. Heads explode, eyes pop and hysterical calls for ammunition regulation start pouring out.

    Next weekends field trip: homemade shotgun shells!

    • And homes had perculators with riser tubes.

      Oh, well, at least 3/4″ galvanized pipe is still readily available.

      • You can find 4130 DOM steel tubing with ID’s just about perfect for a 12-ga shotgun (about .745 – you can even advertise your creation as being “back bored, just like a modern trap gun!”) with wall thicknesses of 0.065 up to 0.120.

        Just look at aviation supply joints. Lots of 4130 DOM tubing is used in homebuilt and kit aircraft. It welds easily (and well), it’s strong, it can be hardened if you wish. Nice stuff.

  3. Hah! I was totally going to cook up a design like this for my own. Basically a bolt action pipe shotgun. Good enough to us, but cheap enough to throw away when you’re tired of it. :p

    • Did your idea look like the Cobray Terminator? I’ve often wondered how easy it would be to make one in my garage.

      • Well right now it’s all rough engineering drawings. But it’s actually roughly based off an old Mossberg bolt action shotgun from the 50s. But this time it’s made from pipe. I’m worried that it might just end up costing way too much to be worth the trouble. But I’ll still finish the design if I can.

        Believe it or not I’ve already got most of it worked out. I just haven’t decided the best way to make a stock yet. Go with more pipe, or make it out of wood. I… just discovered that I had epilepsy a week ago… the hard way. And I’m still getting used to the meds I have to take now. Makes me a bit loopy. >,,>

        • “And I’m still getting used to the meds I have to take now. Makes me a bit loopy. >,,>”

          You will probably develop a tolerance to them in a short while, ask your doc…

        • Oh I know. It’s getting better to cope with. I’ve had it in the past after some neurosurgery. Just kind of makes me wobbly until I get used to it again. :p

          Honestly not being able to drive for about 6 months is going to suck more than anything else.

      • Believe it or not I’ve actually been really thinking about starting a YouTube channel where I make some of this stuff. Kind of like the fellow that does ‘Primitive Technology’, if you’re familiar with that. But given that the Feds want to go after home gun smiths I worry that this will paint a huge target on my back. :/

  4. That thing is far too cool to give to those dipwads. 19″ of 1/2″ gas pipe and a 2×4 with the word “contempt” written on it is all they deserve.

    First time I’ve seen/heard a video with Mark Serbu, he seems like a good guy.

    • I first heard about Serbu about 15 years back when I was googling DIY Parkerizing in the Usenet newsgroup rec.crafts.metalworking.

      And have been a fan ever since. Back then he was manufacturing a .22lr pengun as an AOW, if memory serves.

      • I mean, I’ve known OF Serbu for awhile (Serbu super shorty et al), this is just the first time I’ve seen a video of his.

        Thanks for the link, though.

        Hey Mark, if you read this, teach Royal how to weld. That booger welding of his is shameful.

  5. ” Intended to be manufactured by someone in their basement, the design requires only a hacksaw and drill to turn a length of bar stock into a functioning firearm.”

    Anyone wanna lay odds homemade firearms will be ‘verboten’ with the stroke of pen on an an executive order if the Progressive wins this election?

    Anyone? Beuller? Beuller?

  6. You could easily make this in a shop with an old, clapped-out Bridgeport J-head.

    Oh, I hear the whining now. “Well, that’s easy for you to say, DG. You have machine tools.”

    Well, I’d have machine tools even if I were not a gunsmith. Some of you just have a twisted sense of priorities. You’ve allowed other things to get in the way of having a properly outfitted shop.

    So I’m going to give some of you guys a quick lesson here: How to justify having a shop filled with tools.

    You eagerly take on every new “honey-do” project that comes along. You start the project, getting far enough into it so that it is difficult to just walk away from it.

    Then you develop a need for a tool to get the job done. Don’t mislead, don’t lie. There’s plenty of tools out there today that have been developed to make just about any home improvement job go more quickly – so find the tool(s) that will make that particular job go more quickly, and purchase them, then complete the honey-do list item in aplomb and panache’.

    Or, mention that you could take on job X around the outfit, but it would go soooo much quicker if you have tool X-prime.

    Example: When we owned a farm, we had to dig in a couple miles (yes, miles) of irrigation pipe to feed pivots. I could have hired someone with an excavator – and that would have cost $25K. So I bought a backhoe instead ($16K). Still own the backhoe today. Owning a backhoe makes you king of the neighborhood. Women love you, men want to be you when you own a backhoe. Doesn’t matter whether it’s plowing snow out of people’s driveways, pulling cars out of ditches, digging ditches for cars to fall into, digging out holes for trees to be planted, lifting heavy deliveries off a truck bed…. you name it, a backhoe can do it.

    So you want a Bridgeport (or clone) mill. Well, you should attack a job that requires a drill press. Then you up-sell: “But honey, a drill press does only one thing – make holes straight down. I think we should get an old Bridgeport, because it can do so much more.” NB I owned the backhoe first, so I could use the backhoe to unload the mill from the truck that delivered it. A man’s gotta have a larger plan laid out here…

    Once you have a mill, then you’re on your way to making your own guns.

    • Not doubting you but a lathe would be higher on my list. If I am doing shtf gunsmithing open bolt tubular SMGs are probably the order of the week.

      • You’re absolutely correct. Most gunsmiths until the 1960’s didn’t have a mill in their shops – they had lathes, and those lathes had milling vises that could be mounted on the cross slide. You’d then mount a milling cutter in a collet in the spindle and go to work. You can look in old Southbend lathe catalogs from 70+ years ago and see the milling vises prominently displayed.

        For most gunsmithing, I recommend people get a lathe first. Get the right sized lathe, too. Something in the 10 to 14″ swing, 36 to 60 inches between centers. Getting a lathe that’s too big usually means you give up fine feeds and higher speeds, and getting a lathe too small means you have lots of hassles working on barrel blanks. I recommend a lathe have a spindle bore of 1 3/8ths to allow a machinist to fit barrels down the spindle bore, as well as make a 5C collet closer (if the lathe doesn’t already have one).

        My lathe has a bore of 1.57″. I made up a ER-32 collet holder to chuck up in a 4-jaw. Someday, when I have absolutely nothing better to do, I’ll make a 5C collet chuck or closer for this lathe. ER collets work better than 5C’s anyway. You just need to buy the nut, because the eccentric groove needs to be just right, and the nut will set you back only $20, worst case.

        A gunsmithing lathe should have threads from 4 to 40 TPI (at least), and feeds down to no coarser than 0.0015 or so. Many of the older American 10 to 14″ swing lathes would have fine feeds under 0.001/turn, and that’s ideal for finishing passes.

        HP? Gunsmiths rarely take big cuts. 0.75HP is more than enough. If you have two to three HP, you’ll have everything you ever need. If you find a lathe with a 3 phase motor, don’t shy away from it. Just get a variable frequency drive that takes single phase input and produces three phase output. You get a phase converter and speed control, all in one. My machine tools are fed with 230V, 1-phase, and they all have VFD’s on them. Works great. A 2HP VFD can be had for a couple hundred bucks. Of course, if you want to use an old 3-phase motor and capacitor to make a phase converter, you can do that too.

        If all you do is pistols, you can get by with a smaller lathe – maybe even a 9″ swing, only 20″ between centers. I know a couple of 1911 smiths who have old Southbend 9A’s – and that’s all they have.

        For this particular design, however, a mill comes in handier. That’s the caveat I should have made above – for this particular design of pistol, a Bridgeport would go a long way.

        In my shop, working on existing guns, I probably spend 95% of my machining time on the lathe. There are days when I do have to mill that I have to think “OK, how do I do this again?” On a lathe, I now could probably cut threads while I’m standing up and asleep.

      • Bookmarked.

        “Swarf! Why is there a giant machine in the living room and where is all the furniture?!”

        Well, honey…

    • Yep, I’m thinking the exact same thing – either laser-cut or water jet.

      There’s a shop in Billings that has the mother of all water jets. They’re constantly looking for work to keep that thing busy. I’d wager that they could cut hundreds in a half day if the thing were fed large chunks of plate.

      • DG, looking at the video, when firing, the breechface slams on the rim, is that not the very definition of an ‘open bolt’ that can get one ten years in the federal pen?

        And playing around with the mass of the slide and the spring rate you could get the casing to auto-eject on you.

        It’s a short step from an auto ejecting shell casing to adding a magazine of some sort turning it into a bona-fide machine pistol that can also get you 10 years in the slammer…


        • I recall a ATF policy letter from the early 80’s that addressed the issue of open bolt in the context of semi-auto guns that could be converted quickly to full-auto, by virtue of merely removing whatever parts held the bolt open after the first shot until the trigger was cycled again.

          This piece – has no magazine, it doesn’t even have an extractor (you have to use your fingernails to remove the casing), and the bolt isn’t being blown to the rear after the shot – it just sits there, closed.

      • Only need the PDF drawing, can convert to dwg in the time it takes to chew a pop tart in the shape of a gun.

      • Oh, that looks tasty! I hope a MakerSpace near me gets one.

        That vid has ‘Bunny’ Huang in it!

        He is a *serious* uber-geek, first became a fan of his with his blog post on counterfeit flash cards, well worth the read if you are considering buying an eBay too-cheap-to-be-true micro SD card:

        One of his newer projects is an open-source laptop with an on-board 300MHz-3.8GHz SDR *transceiver*

        He’s the kind of guy who could actually pull off an open-source cell phone with a broadband SDR transceiver in it if he ever put his mind to it…

      • 6 grand for a desktop waterjet is out of my reach, I hope a local fab shop gets one.

        I never could figure out how waterjet cutters keep their nozzles from being eroded away by the abrasives passing through them…

  7. The fact that a well known firearm manufacturer is engaging in this type of thing is mind blowing (though really cool)… Mark Serbu is the antithesis of Bill Ruger.

  8. I’m amused that coolant sprays on his machine came off of, or are the same as the ones on, a cold air gun.

    • In fact, some CNC machines are using cold air streams instead of coolant. There’s several manufactures of Hirsch tube designs that take compressed air and produce really cold air (and hot air byproduct). The cold air is directed through nozzles very much like what you see above at the tool.

      Whether you use coolant (which is usually water-based, with a semi-soluble oil mixed in) in a flood system (which you see above), a “mister” which uses regular compressed air with a mist of cutting oil, or an air chiller, most CNC operators want something to blow the chips out of the cut. On a manual mill, you’d be in there with a chip brush, pushing chips out of the way of the cut, but on CNC machines, the tool is removing far too much material, far too quickly, for the operator to keep up with the chips.

      Most CNC shops will use flood coolant as you see Mark doing. The reservoir on the CNC machine is probably about 55 gallons, and the pump is about 0.25HP. After you’re done machining for the day, the inside of the enclosure will be covered in chips – so what you do is open one of the windows on the end, and pull a hose around from the coolant tank (which will be on the back of a Haas such as the one in the picture) and you spray down the inside of the machine with coolant to force all the chips down into the auger trough. When you’ve pushed all the chips down into the trough, you push the “Chip FWD” button on the control and the auger pushes the chips out into a bucket off the end of the machine.

      In a manual shop, we pick up a broom and a square-nosed shovel.

      • CNC machines are cool. I’ve never gotten to use one but I’ve run just about every other machine you can find in a machine shop. Honestly, I’ve never worked anywhere where we needed one. In the first instance the robots did a lot of the work on pre-shaped items and in the second case we did all the work but there wasn’t anything we couldn’t do with a welder, band-saw, drill press, mechanical press, steel bender, lathe and a few other assorted tools.

        I used to work for a place that used Vortec cold air guns to cool our welds on stainless and hastelloy. The brand is severely overpriced but the gun works quite well. They used to come with exactly the tubes he’s got on his machine. If you completed a weld on a unit and turned on the gun right before a break you’d come back 15 minutes later to find the object you were welding covered in a thin layer of ice. Ah… the days of working for a company that had more money that God and would buy any tool you requested at the drop of a hat. Too bad they didn’t pay very well but hey, you can’t win ’em all.

        Personally I’m a fan of using air. Cutting fluid makes a mess that’s a real bitch to clean up.

        An interesting side note; while vortex based cold air guns are common and known to work, exactly how they function is unknown. After using one for a few weeks I tried to find out the physics of how they function. No one knows! The physics behind them is not fully understood. They work and no one is going to dump millions into studying exactly why they work. No grant givers care about it enough. I guess they’d rather find out what happens to shrimp on treadmills.

        • Yup, I’m familiar with the physics conundrum surrounding Hirsch tubes. I studied them in high school – they were (and are) fascinating to ponder “WTF? How does this work? It is working, there’s no doubt about that – but why/how?”

          When I get a few more bucks to rub together in the shop, I might buy a Hirsch tube setup. A mister is what I have on my mill now, but that gets messy quickly. So does just squirting on high-sulphur dark cutting oil, which is my preference in cutting lubes. Yea, I’m old school.

          CNC machines are fiddly creatures to operate. If you’re doing one-offs, it is often easier to get something cranked out on a manual machine. When you want to do pieces 10-infinity, then the CNC machines earn their keep. One really frustrating thing about CNC machines is that when you’re developing a program, your cutting action is hidden by the flood coolant – you can’t see what’s going on in there. Another is that they break tools with ruthless efficiency when your program is wrong – and some of those tools get spendy. The first time you botch a rigid tapping cycle on a CNC mill, you’ll know it – your tap will be driven into the workpiece with utter impunity and a gut-wrenching sound. Then the little red light will come on, and you’ll turn the air blue.

          You’ll rarely use HSS tooling for big volume removal on CNC’s – you’ll be using inserted and solid carbide tooling to get your speeds & feeds up. Modern HSM toolpaths, created by CAM programs, make a manual machinist like me go into “Pucker Factor 11” at the control station the first few times I see it. The tools are wound up to seemingly impossible RPM’s, and they’re being driven into the workpiece at “Holy crap!” speeds. But no one can deny the HSM boys are getting real and profitable results.

        • As a recovering welder I hate cutting lubes. They’really almost impossible to remove completely and they smell/taste like shit.

          Nothing ruins your lunch like the lingering after taste of that stuff being burnt. You can wear a charcoal filter mask but that’s a pain in the ass under a welding helmet because it pushes your safety glasses around and it’s just a pain to deal with.

        • Try dipping the workpiece (if you can) in hot muriatic acid. That’s what I do prior to TIG welding gun parts, and it helps.

          Another welder I know uses lye-based cleaners to strip the oil/grease off parts.

          I know what you mean about the smell. When the workpiece gets hot on a machine and the smoke starts coming off the tool, it ain’t a wonderful experience either.

        • For the physics of vortex tubes, Wikipedia says someone figured out the basic principles in 2012. Something about enthalpy conservation and Euler’s turbine equation.

        • I don’t weld for money any more. I’ll do my own jobs and some stuff for friends but other than that I don’t need to deal with it any more. Grad school baby!

          Also, chemical cleaning methods like that would have been verboten in any place I worked as a welder. Once I got out of TIG work on hastelloy and stainless and went back to straight carbon steel (which surprisingly paid better) that’s when I really got back into cutting fluids. No way in hell would that place have let us clean the stuff chemically. The best way to deal with it was to drop it in a water tank and then hit it with a grinder and hope you got enough of it off that you didn’t get a cloud of smoke when you struck an arc.

          I fucking hate cutting fluids but I understand why they are necessary (Screw you Mr. Band Saw Blade!). Most have some oil base to them, so when I do smaller stuff around my house I actually coat the piece in Dawn dish detergent, hit it with a hose and then blot it dry with a paper towel. It takes a fair amount of extra time that wouldn’t have been acceptable when I was getting paid to do this.

  9. I like this concept.

    A kit that can be sold cheaply and assembled with just an allen wrench would be great.
    Most people just don’t have the tools to machine one of these, but could blue a kit, or apply a powder coat,
    or just assemble it.

    I’d like to see it rifled, and maybe not open bolt, unless you can get the atf to sign off on it
    Maybe some sort of really simple bolt or lever lock.

    Dovetails for some flavor of standard handgun sights would be nice.

    It would be nice if it extracted the spent round, too.

    If it can be assembled with bolts, it could be modular, and multiple caliber.

    Just change the barrel block, if it’s a locking breach of some kind, otherwise barrel block and recoil spring.

    I realize these modifications take the weapon out of it’s intended role as buyback fodder,
    but they would make for a great little target piece, And it should still be pretty cheap.

    With no other modifications than selling it as a kit which anyone could bolt together, it could fulfill it’s intended purpose.

    Two different kits, maybe ?

    • Your over thinking what it is. Two camps Gun Buyback and Gun Defiance. Arms in this country shall not be infringed. I’ll build one for 22 mag

  10. Hmm… I just had a thought. We all know that these buy backs pay more for ‘assault weapons’ and pistols than they do just old long guns. What is the exact definition of ‘assault weapon’? Are we just talking about any auto loading long gun or is it caliber dependent? Because if they’re paying 250 a pop we can probably piece together a auto loading 9mm or .380 carbine.

    • “Assault weapon” means it is black, and scares soft-shoe liberals who listen to NPR while driving to their think-tank jobs in their Volvos.

      All we need is an injection molding machine. It doesn’t have to actually even be a gun. I’ll bet if we stuck a piece of non-functional, center-drilled CRS into a mold and pumped in all the furniture profiles of an AR-15 around it, we could make bank on the project.

      • Heh. Yeah, that would probably work just fine. Although I was honestly thinking more along the lines of a simple STEN carbine. Something legal as is as that takes the wind out the ability to push for prosecution. But also enough to net the biggest around of money possible from these stupid programs. :p

        • I like your thinking. The object of this lesson is actually to drain their coffers, not cause them to load up their Depends.

          Yep, gotta keep our eyes on the ball here.

  11. If you make a crude pistol caliber rifle, then attach some black plastic furniture from a cheap airsoft onto it, will that make it an “assault rifle”? I’ve read they pay a premium for “assault rifles”.

  12. So what’s the”going rate” at these buy backs?
    Is it per gun, is there a limit?


  13. Tom in Oregon is my hero in this area.
    Keep in mind that gun haters are ignorant of what a firearm is. Tom bought scrap pipe, made wood handles, a rubber band striker (or something similar) and wrapped the handle in tape.

    Fooled them all, depleted the enemy’s treasury.


  14. Thanks so much for the mention of vortex tubes. The Wikipedia page for Ranque-Hilsch vortex tube provides detailed information that’s a great read for pseudo engineering types like me. I’ve referenced the excellent technical discussion on this page to several people as another great example of the value of the exchanges between this subset of POTG.

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