Boberg XR9S & XR45S: The Bullpup Pistols

Rock Island is selling these two Boberg pistols as part of a Lot 1089 in their upcoming Regional auction on February 14th, 2019.

Arne Boberg founded Boberg Arms in 2009 and released his first pistol in 2011, the XR9-S. This was followed by the longer XR9-L, and then the XR-45S in 2014. The conceit of the Boberg pistol is basically that of the Bullpup rifle: maximizing barrel length while minimizing overall length. To this end, Boberg used an unconventional system of pulling cartridges out the back of the magazine rather than pushing them forward, allowing about an inch of extra barrel in a given pistol. The resulting feed system is a bit complex and very cool, and reminiscent of the old British Mars pistols. It is not without its faults, though, and the lowest priced Boberg pistols were over $1000 retail, which significantly limited their sales in a concealed carry market awash with good options at half the price. In 2016 Boberg sold the gun to the Bond Arms company, which markets is today as the Bond Bullpup. Original Boberg production guns have, thus, become collectible items for those interested in unusual handguns.


  1. Automatic correction misspelled “concept” as “conceit.” That aside, this is a well-meaning concept gone horribly wrong due to production costs. I wonder how anyone thought the Browning style compact pistols (both in blow-back or tilting barrel locked variants) were too bulky for concealed carry… to say nothing about the PPK or even the Beretta Cheetah, both of which are pretty good for “get your mitts off me” encounters.

  2. Co-worker bought one of these in 9mm a few years ago for his back-up / off-duty carry. Really neat little pistol, but it was VERY finicky about ammo. The pistol came with a list of recommended factory loads and while it was a decent selection, all of the loads were lighter bullets, nothing over 125 grains, and our issued ammo wasn’t on the list. We shot some duty ammo anyway and confirmed it wasn’t going to work. I suspect the magazine did not have a typical follower so as to make it easier to clean out the un-burned loose powder that gets dumped out when a case is yanked off of a bullet.

    Still want one.

  3. So here we go: Bobby is FW already!

    And, what else to expect. Invent, patent, make and mainly sell something like cost lots of money. It’s like pixxing against the wind. Not a chance to win with something so unusual unless you match price with ‘primitive’ Glock at which point you go bankrupt. Great lesson for inventors, worldwide.

    • It helps if your invention actually results in something that has a noticeable improvement over existing designs, in one way or another, and *doesn’t* simultaneously fail to provide any significant improvement in cost, performance, etc., while also bringing in new flaws that your competitors do not share.

      Yup, if you want to be a successful inventor, you need to create a successful invention. “It works significantly worse and has no major advantage at all, but it’s way more expensive” is not “successful”, no…

      • Yet, I have to admire Boberg’s “pioneering” spirit. 🙂

        When I consider his possible frame of mind – laid off with existential threat, he had to do ‘something’. On top of it he demonstrated to his former employer what they lost in him. I was in similar situation one time.

        • ““pioneering””
          After some thinking I concluded that Boberg achieved similar feat (high barrel-length-to-overall-length radio) but in much different way to… Dardick. Consider namely DARDICK HANDGUN SERIES 1100, see 3rd image from top:

          designed yet in 1950s, though DARDICK HANDGUN SERIES 1100 is fatter, due to rotor (? I am not sure about correct name of that element ?). DARDICK felt into oblivion due to time-consuming procedure of loading cartridges into magazine and using untypical (and unorthodox by 1950s U.S. standards) ammunition, but still have bigger capacity (11) than Boberg.

    • Of course, even Glock is willing to change given enough reason;

      Incidentally, the final production model has 1911-type ambidextrous thumb safeties, admittedly mainly for purposes of field-stripping. On the 46, you no longer have to fiddle with the trigger to remove the slide/barrel group.

      Hm. Glock has finally come up with a 9 x 19mm I’m somewhat interested in.



      • This was a surprise to me when reading about it first time. I thought the PX4 was the apex and ‘end of all rotaries’. Sure, there are solid reasons about keeping them (energy attenuation, accuracy…). The product cost is higher than with flappers though. At least on civilian market the PX4 always costs more than a Glock.
        With that is of course connected question why Beretta gave up on it.

      • Glock 46 seems the continuation of tendancy of using nearly a century old take down method of dragging the barrel with slide fore and up through the frame rails, first used in Mauser HSc, moved on with Vz52, HK4, HK9 and temporary stopped but reinvented by Bubits on BB6 and continued with new Mossberg pistol and Glock 46 with a difference that containing frame stop and take down key piece at back. Fredrich Dechant the inventer, seems managing the rotating barrel take down through a very reasonable method after trying and patenting a few childish construction. Through this take down, the striker spring losts its power as its back support being taken away and the need of dry firing before disassembly is out.

        lt is said civilian purchase of Glock 46 is not possible.

        • Another later article said that a civilian version will be available later this year from Glock USA.

          As for “dragging the slide and barrel off the front of the frame”, there was a sound reason for that from the start. Namely, that self-loaders with bolts or slides that could be removed backward could sometimes fracture their stops and be projected forcefully backward on firing-right into the shooter’s face. The Schwarzlose Standart and Mauser C/96 both had this problem, the Mauser in particular as all that keeps its bolt in the barrel extension on recoil is that single little block the recoil spring bears against. If it shears, say hello to an eyeful of DWM steel.

          Later designs are not exempt. The Kimball retarded-blowback pistol in .30 Carbine, build much like a Colt Woodsman .22 rimfire, had a short slide retained by two stop-blocks machined into the rear of the frame. If they broke, the slide would be launched straight back at considerable velocity. Due to inadequate heat-treatment plus sheer operating stresses, most Kimballs still extant have at last one stop block either cracked or broken entirely off.

          As you might expect, it was John Moses Browning who first came up with a slide/barrel group that could only be removed forward off the frame, precisely to avoid this kind of accident, with his Modele 1900 automatic for FN. A feature carried over to all of his subsequent pistol designs.

          Ironically, or maybe predictably, during WW1 the German Langenhans 9 x 19mm pistol, externally an FN 1900 “clone”, had a powerful recoil spring to allow the blowback action to accommodate the powerful 9mm Parabellum cartridge. To ease loading, a lever at the top rear of the slide allowed the inner bolt to be disconnected from the recoil spring. With wear, this lever could flip over in recoil- and the bolt would enthusiastically try to kill the shooter, rather like a Ross rifle bolt.

          (NB: The Ross rifle bolt hazard is not a myth; I have dealt with Ross rifles, both military and sporting, and never found one that could not have the bolt assembled incorrectly, resulting in firing in the unlocked state.)

          The forward removal of slide and barrel on an automatic pistol might seem “old-fashioned”, but in actual shooting it’s considerably safer than the other setup ever was.



          • Thanks Eon… But what l wanted to say was, the new popularized take down process needing a slight forward move of slide and barrel and up to be disengaged, instead of more popular direct forward and off. The fore movement of disengaging slide in this two way movement application is so short that, the striker in the slide can not get enough compression for a discharge as precluding the necessity of dry firing beforehand… However,
            both Mossberg and Glock 46 also ensure this handicap as getting the striker spring functioned away.

    • “Great lesson for inventors, worldwide.”
      I would rather say entrepreneurs. Great question is how to convince buyers that product is worth buying.

      • Partial answer to how to convince buyers that product is worth buying:

        Produce a product that actually is worth buying, and doesn’t cost MORE for WORSE performance, while offering no significant advantage IN ANY RESPECT.

  4. “maximizing barrel length while minimizing overall length”
    Barrel long, pistol short?
    Maybe in order to do so, other over 100 year old design might be used, namely Schwarzlose 1908:
    blow-forward, works with 7,65 mm Browning [.32 Auto], would need further experimentation to detect how it would cope with heavier cartridge. Also more importantly how does rifling affects dynamics of such system. How it would work with hexagonal barrel bore? How it does work with few big grooves vs a lot of small? Could it be used with progressive rifling?
    Finally I am wondering if blow-forward could be cross-breed with Gas Bremse principle (as found in Steyr GB)?

    • Not sure if gas break would work, because… The bullet moves the barrel forward via the rifling, so you’d be preventing the barrel moving… While the bullet is travelling.

      The Schwarzlose does/could end up with a similar result though, from memory I.e. The extra barrel length, but in blowback.

      Did the Mars have the bullet pulling problem. Seem to remember having a similar conversation before…

      • Twin mag, cross of this and your idea; forward mag infront of this ones position, operates as now, but with blow forward also, fires as per but then blows forward slide catches up loads again fires, moves back loads boberg style; double tap.

        Mind you I am drinking wine.

      • “preventing the barrel moving… While the bullet is travelling.”
        Please note that pressure is NOT constant during whole bullet travel through barrel, so in order to making it work, it would need to be such balanced that at certain point, when bullet is still traveling down the barrel, braking force becomes lower than barrel pulling force.

        • Yes I can see that, I could soon as I posted it; well only one way to find out have you got a drill and a Schwarzlose I haven’t. Make a estimated guess… You could always weld bits onto the slide to increase its weight, so a welding machine also.

          • Oh no you could’nt… Er, well you could make the barrel heavier; welding required and a saw now.

          • I reckon you start in the area of the GB’s, after making the barrel similar in weight to its slide… This is probably going to take longer than initially expected.

            Er… How about a reverse… Luger… Toggle… I’ll need to draw it quickly.

          • I’ll think about that more anyway, thanks for the notion; probably be a 3,000 comment one though so, I’ll desist from sharing everything I think of in between.

        • Barrel has to move (rotate), it has ho choice since it is dragged back with slide. Now comes the trick part. Should it rotate clock-or-counter-clockwise? Bullet spin reaction into barrel tends to turn it opposite to sense of rifling. I once in back looked into it and found there was not clear uniformity; some (majority) rotate against the reaction and some with. To me, this is great opportunity to dump and much slide momentum as possible so that user feels less of it in his hand.

          • It probably helped in two ways.
            First, necking the original .45 round down to 9mm or 8.5mm meant going from a 220gr bullet to 156gr or 139gr. The reduction in caliber isn’t all good, because the crimp circumference also reduces linearly with diameter, but the mass reduction is (in this case) faster than linear, so the inertial force trying to extract the bullet reduces by more than the crimp strength does.
            Second, the smaller caliber bullets unsurprisingly had lower momentum (and thus recoil), probably yielding less violent operation. (Though I’m not certain that the moving parts were the same mass on different-caliber Mars pistols.)

            A third potential reason (which turns out not to apply in the case of the Mars) could be the fact that bottle-necked rounds generally headspace on the shoulder, and may be crimped as desired, whereas the straight-walled rimless cartridges we think of as conventional for autopistols (9mm, .45ACP, etc.) are designed to headspace on the case mouth, which limits the depth of crimp so the case mouth isn’t too tapered/rounded to reliably seat on the square step in the front of the chamber.
            But of course there’s ways to headspace without a shoulder or squared-off case mouth, the most obvious choice being to headspace on the case rim. (Typically with a semi-rimmed case, but you can also design an extractor to headspace a rimless case off its extractor groove.) The Mars pistol in .45, on the other hand, did have the case severely crimped with a chamfer, such that there was no flat end to seat in a normal chamber, yet it still headspaced on the case mouth. The front of the chamber was tapered to match the crimp angle.
            I’d call this a very unconventional choice, but it’s important to remember the Mars design dates to an era before we knew what “conventional” autopistols and cartridges would turn out to be. At the time, John M. Browning was still designing semi-rimmed cartridges, and it would be 4 years till Luger would introduce 9mm, the prototypical rimless, case-mouth-headspacing cartridge.

      • The Mars pistols all used proprietary cartridges from what I recall, so if the cartridge had separation issues, the spec could easily be changed to use a more robust crimp.

    • Blow forward guns seem to have unpleasant recoil. Probably something to do with conservation of momentum and that equal and opposite nonsense.