Prototype Pieper .45ACP Pistol at James D Julia

Nicholas Pieper designed a blowback pocket pistol which was manufactured under license by Steyr in 1908. It was a reasonably successful pistol, and can be found today in .25ACP and .32ACP calibers. This particular one is an experimental version scaled up to .45ACP, with the intention of making military or commercial sales in the US. One unusual trait it shares with the smaller versions is its lack of extractor – as a blowback design it will function without one, but the shooter must break the action open to manually remove an unfired cartridge.


  1. Tip up barrel autoloaders have the advantage of loading and unloading the chamber without manually retracting the slide against to force of return spring. This means, very stiff springs can be used to soften the jolt of recoiling slide. Such a this kind of pistol using powerfull rounds like .45″ACP, this might be expected but, appearently, designers did not used this very convenient feature. Thanks Ian for this video. It shows that even the big, well known brands may behave unrational.

    • You could load it manually initially, then close the barrel to engage a “strong” spring – One that would be difficult to pull back via the bolt, this one doesn’t seem to have a strong spring though which as you say it could have.

      Maybe it cycled so fast, gas was lost through the ejection port while the bullet was still in the barrel so the projectiles had less velocity and therefore the recoil wasn’t as strong i.e. The bolt force against the spring.

      • As all known, there are two main purposes using breech locks in firearms; first to put the highest push force behind the projectile to get the aimed velocity and punch force, and second to prevent both the gun and the user to be beaten by recoil impact using the maximum joined mass as lessening the breechblock speed. A big brand like Pieper should absolutely be aware of these basic principles and the cause of why not figure out a firearm staying out of them is questionable. Wasting the obtained force from the wrong end of barrel, would cause some side effects harming both user and gun. A tip up barrel gun like this one has the big advantage using powerfull springs as buffering the violent punch of recoil force precluding the use of manual slide retracting and why Pieper Staffs happened as not using it must be the question. There should be a hidden aim with this supplied form of pistol that seemingly not been influenced.

        • Maybe they just thought to wing it, hoped it wouldn’t be that noticeable. I half imagined the Pedersen M53 was kind of the same thing, gas escaped out the ejection port because the case didn’t expand properly in the chamber due to it blowing back instantaneously sort of thing. Because it was lighter overall than it should have been to provide a longer delay, but the design needed to be in order to work anyway so I am not sure. I thought maybe they figured a slight loss in velocity, was worth a more svelte gun.

          • Parallel sided case of .45″ACP generates more friction than tapered sided ones and, neglecting the case seperation, this reduces the slide recoil speed with healty gas sealing. Besides, the burning speed of powder charge starting at rear is more in larger diameter rounds like .45″ACP and all of those are significiant advantages for slmple blowback working system. Savage 1906 with a very weak lock up and Remington M53 with useless delay action may be proofs for this approach. Pieper staffs should have been discovered those with experiments more earlier and this pistol might be a reflection of this effort. Hey! It goes really serious.

    • As did the JoLoAr in terms of barrel being on a hinge. Interestingly, nobody has used a “one-handed” charging approach like the JoLoAr. The “Einhand” system was reused by China in the Norinco 77B, but the charging handle (which is optional and part of the trigger guard) must be pulled with one’s trigger finger (not for those with small hands). Why not just use a separate charging lever like that in the JoLoAr for ease of one-handed rack on the draw?

      • Depends how strong the spring was, by tipping the barrel you could use a gas strut out of an air rifle which would be difficult to compress one handed with a handle.

      • In the 1907 trials, there were two White-Merrill .45 pistols entered. One resembled the gas-operated .45 prototype developed at Springfield by Capt. W. A. Philips, Army Ordnance Dept., and may have been designed by Philips as a more refined version of the Springfield pistol.

        The other was a short-recoil pistol using a variant of the Colt-Browning locking system. It had what looked like a huge external trigger on the lower front of the trigger guard, which was actually the handle of a ratchet-like system to allow the slide to be racked one-handed rather like the Jo-Lo-Ar. Due to the limit of travel, the lever had to be squeezed twice (rather like a grip exerciser) to run the slide all the way back and then release it to chamber a round and cock the single-action hammer;

        The Army was still thinking in terms of horseback operations and wanted a pistol that could be manipulated one-handed while the reins were in the other hand. The White-Merrill pistol was turned down, however, on the basis of being too complex and not showing the reliability the Army insisted upon. It apparently failed mechanically at 211 rounds.

        These may be found on pp. 322-334 of Handguns of the World by Ezell, which show most of the 1907 Army trial guns. Oddly, there is no mention of the Pieper.

        I might add that blowback pistols without extractors have a flaw which could prove deadly in an actual IA. That being that you cannot deal with a dud round by the standard Tap-Rack-BANG method. That just double-feeds a live round up behind the dud, thoroughly jamming the whole production. I have never used a blowback that does not have an extractor for serious purposes for precisely this reason.

        Honestly, a compact DA revolver in .38 Special or better caliber still trumps most “compact” autos for such purposes. Five or six almost-certain shots beats six to twelve “maybes”, every time.



        • An extractor is only a little piece of metal, it probably costs more to have a tip up barrel… You can see why they tried it though, it seems a good idea until you perhaps think about it more i.e. It’s only wee bit of metal after all.

  2. Interesting gun, the bolt appears to have little mass for the calibre in relation to say the slide of a Highpoint another blowback design. Is it deemed ok because the bolt can’t go anywhere i.e. Because the frame is closed behind it. Just thinking why a Highpoint need be so bulky, I figure it must be because it uses slide rather than a bolt as alluded to above. The spring doesn’t seem to give any more resistance than usual, given it has no ejector is it probable then that because the bolt/spring don’t provide much resistance the blowback takes place earlier than in say a Highpoint? Giving a high cyclic rate so to speak, because its operating at a pressure that would usually be deemed unsafe.

    • But the bolt can’t go anywhere, so it was deemed safe. Maybe operating like that wasn’t conducive to making it reliable though, bulged cases perhaps, getting stuck in the ejection port maybe. Be interesting to see it fire in slow motion…

  3. I wonder how fast this thing cycles… Considering that the bolt does not seem to be very heavy and neither is the recoil spring exceptionally stiff. Even if it kind of works (which is must have done), it has to be a veritable “gas gun” with a lot of gas vented through the ejection port. A slow motion video of this gun firing would be very interesting. Too bad there is probably no chance of that happening considering how rare it is.

    • Maybe that’s why it was rejected, it worked reliably but the projectiles lacked velocity and therefore oomph because if the amount if gas that escapes.

    • Firing even a relatively low-pressure round like the .45 ACP (21,000 PSI vs. 35,000 for 9 x 19mm), I would expect that the bolt movement could be fast enough that there would be frequent “ride-over”, i.e., instead of picking up the top round in the magazine and feeding it, the bolt would simply go over top of it and shove it back down into the magazine, resulting in a failure to feed.

      The trouble is, from the shooter’s POV, there would be no way to see that this had occurred.
      The shooter’s first notification of this failure would be when he pulled the trigger and got a “click” when he really needed a “BANG”.

      Not a good thing.



      • I didn’t see an ejector, can’t remember… I heard somewhere NAA Guardians eject off the next round in the magazine, and lack an actual ejector don’t know if that’s a fact. But given what you have just said, if that is the case it that could perhaps be problem.

        • Still can’t see one, there’s a gap on the bolt face though so there might be one further back that you can’t see. It’s no feed ramp either…

  4. If you put a port from in front of the chamber, above the bullet. Upon firing gas could pass into the springs guide etc rod via a so |\ angled cut to impart extra resistance until pressure dropped in the barrel.

    • Said angled cut, being made in the springs guide extra rod above the port aforementioned.

      Might be alright if your trying to make a cheap gun…

    • You might be able to make it all out of aluminium, aluminum… I.e. Insert a steel barrel, bolt. Might be lighter than a aluminum framed, steel slide pistol for example.

      I don’t see why the gas delay thing wouldn’t work, if you fit an extractor you could do away with the tipping barrel.

  5. Does it not have an ejector then I know the case isn’t stuck to the extractor – As it there isn’t one, but I mean… A knocker outer, how do the cases find there way out the ejection port do they just find there own way out or?

    • On most non-extractor blowbacks the empty more-or-less just bounces off the breech when the latter is at full recoil. The ultra-small Beretta .22s and .25s used to use this method.

      Yes, there is a risk that a load with a lower MV will result in the empty not having enough rearward velocity to “bounce”. Instead, it can get caught between the breech and chamber mouth, resulting in a classic failure-to-eject jam. And as with the dud round, a Tap-Rack-BANG may or may not work to clear it.

      Some non-ejector blowbacks, notably .22 Shorts, have a nasty habit of ejecting higher-velocity “outdoor” loads more-or-less correctly, but consistently pushing medium-velocity “indoor load” empties right back into the chamber by scooping them up off the top of the magazine where they come to rest after popping out of the chamber and not hitting the breech hard enough to bounce away. One more reason that anyone who believes a .22 Short is enough power for a hideout would be well-advised to stick to a mini-revolver as its launch pad.

      Although the mini-revolvers pretty well end the argument overall. Some of them are available in .22 WMRF, which has nearly the oomph of a .38 Special.

      And their small slugs, with that powder load behind them, have serious penetration except for the HPs that tend to blow apart inside the target. A .22 Magnum mini-revolver loaded with either one would probably be a more sensible choice than a mini-automatic that may or may not work as advertised when it drops in the pot.



      • .22 WMR is not actually that powerful from a handgun. Factory loads use rifle powder, which means that muzzle velocity from short barrels is surprisingly low. 40 grain bullets launch around 1,200 fps from a 3″ barrel, which is about .32 ACP muzzle energy. More powerful than .22 lr for sure, but I think I would rather use a small .32 ACP pistol than a mini-revolver chambered for .22 WMR. The length of the cartridge means that a .22 WMR revolver is going to have a fairly long cylinder, which puts a limit to compactness. I have also heard that there are bullet stabilization issues with .22 WMR and short barrels.

        • I heard that in very short barrels 1″ etc, all the powder doesn’t have chance to burn before the bullet leaves the barrel in .22WMR. I wondered if you couldn’t put the projectile inside the case and crimp the end over it like a blank, the bore would be adjusted to match the smaller diameter bullet – Idea being to slow it’s exit from the case somewhat, in order for more powder to burn.

          • This is the cause why Georg Luger invented “Stepped Chamber” at beginning of the last century; Providing more time for burning powder charge behind the bullet and more swaging for its back to sit into the rifling grooves to minimize the gas escape. Still been using some short barrel German pistols.

            This Pieper seems having an ejector. The screw head at left side of frame at behind breech section, appears as if its retaining piece. Non ejector pistols generally get along well with open top barrels, or in other case,
            the empty case in front of the breech face of slide may not decide where to go eventualy sticking in its walk about area causing a jam.

            Most outstanding feature of this kind of pistols carrying the return spring located over the barrel in the receiver, is their capability of being buılt in the equal outside thickness with the barrel since the lack of slide side walls at both side of the barrel. Thinnest pistols are contained within this cathegory.

            If noticed, this pistol has very short feed ramp and deeper chamber to support the case body. It has also two
            angled cut channels at rear of chamber opening to the counter recesses cut in the frame. This means some powerfull gas escape occurs at instant of firing, but at last stage of case journey within the barrel by cause of parallel sided construction and fully supported chamber. These are also powerfull helps for blowback operation.

          • That stepped chamber looks ideal, the cartridges are sort of Nagant’ish Is that right, the bullet has to squish through type thing.

            Sort of a choke, I had a similar idea using a split ring that would sit around a groove for it in the jacket it would require to squish through a choke in the revolvers chamber leaving the rings behind… The stepped chamber seems more practical, mind you if the gun didn’t have a stepped chamber the crimp thing might be similar – Although it wouldn’t have the correct barrel.

            Anyway probably worth doing something along those lines, to get extra oomph out of a .22WMR mini revolver say.

      • “Some non-ejector blowbacks, notably .22 Shorts, have a nasty habit of ejecting higher-velocity “outdoor” loads more-or-less correctly, but consistently pushing medium-velocity “indoor load” empties right back into the chamber by scooping them up off the top of the magazine where they come to rest after popping out of the chamber and not hitting the breech hard enough to bounce away. One more reason that anyone who believes a .22 Short is enough power for a hideout would be well-advised to stick to a mini-revolver as its launch pad.”
        What about .25 Auto (.25 ACP)? Is this a unique trait of .22 Short or it is rather total normally “to light powder charge to cycle action properly” issue?

        • I think that is mainly an issue with .22 short target loads, which are intended mainly for indoors and typically have a muzzle velocity around 650-900 fps from a rifle barrel. Typical .25 ACP loads have more muzzle energy than even most high velocity .22 short loads from a short (<3") barrel, so I don't think that should be a problem with them (.25 ACP is usually loaded with a fast handgun powders, since hardly any pistols chambered for it have a barrel longer than 3").

  6. I like the looks of this gun, it’s “barrels” remind me of an under and over saw handled flintlock I saw, with browned barrels. You could brown the “barrels” in a pistol of this configuration now, case hardened frame, saw handled’ish grip via it’s bolt at the rear resembling that of the Wilson match pistol on this site.

    • You could Lancaster pistol it also i.e. The design as now, but with four “barrels” and two magazines. Who’s seen the double barrel 1911, I bet you could make a double barrel semi auto in this format lighter than with a slide. Gas delay, double triggers one per action.

      • Bet they’d sell, particularly if you made them attractive as alluded to… 10mm Hunting guns, rapid double tap – Safety from enraged Boars or something kind of a Howdah lark but self loading, you’d fire a barrel at a time via pulling one trigger then the other say like a side by side shotgun.

        Wouldn’t be as big as a Mars pistol.

  7. This is “cheeky” design (due to lack of positive lock) but I like it. Why to make it complex if it goes simple, right?

    • I like it as it is, I am just thinking it wasn’t particularly successful. And at the time they didn’t know about gas delay, as far as I know and to me it looks eminently suitable due to the layout. So given it’s safe, because the bolt is enclosed, slowing down the cycling speed might help it be “successful” in .45acp for example.

  8. Hi, Denny, but for a 9mm Parabellum version would not be simple and easy like this .45″ sample. Higher chamber pressure and tapered case walls would be the main negatives. But shortening the barrel would be an alternative. If noticed, there is a trend of using short barrel pocket pistols nowadays and there are two succesfull pistols in market one from Germany with gas brake and another from The USA with hesitation delay. Both pistols are using these quasi lock devices mainly to dampen the recoil force rather than lock mechanisms providing highest possible gas pressure load behind the bullet which seeming nearly needless for the barrel lenghts they use. Main purpose of these handguns to get easy manually slide retraction and lower felt recoil. If a third to be manufactured, it may or will be this kind of tip up barrel type with stiff return spring.

    • It would provide a method to use a strong return spring, because you wouldn’t have to operate the bolt by pulling on it as it could do cycle upon firing after you load the first round via tipping the barrel but I think gas delay might be better personally – Suppose it depends on how strong of a spring you could fit inside it. Although now we know about gas delay perhaps that would be better as you’d just drill a port through the top “barrel” into the chamber, the spring guide etc rod would cover the top hole and if said rod had a notch in it above the port gas should present a form of resistance.

    • I follow on what you say, Strongarm

      the only thing against “stiff” spring IMO is the relative interaction of bolt-magazine. I think Eon already spoke in that sense. As you say, this can be hardly practised with 9mm Luger which is mainstay in pistols. So it appears, this may be more or less fringe affair.

      • Bolt/Magazine co-work is very important in using stiff bumper springs and this means, it comes the time to use cam assisted magazine feed up in coorelation with reciprocating slide.

        Regarding to gas delay, difficulty rises in using tight moving tolerances and clean operation working area in lock similar using. But in sole dampening use those may not be necessary.

    • Just to fill in following thought (as PDB is doing with such a favour)…. -)))
      I have still hopes for new gas-brake type of pistol. Germans and to some degree Austrians have done bulk of work. Now is some other people’s turn. On barrel length, I do not have lots for taste for 3″ length regardless of caliber; I’d say 3.5″ would be absolute minimum for me.

      • If the Walther CCP is a success on the American concealed carry market, maybe some other company will copy the concept. The Remington R51 is still a no-show after they stopped production (Remington’s press release says that they expect to resume production in October, which obviously didn’t happen), so the CCP does have that particular niche all to itself (I don’t mean gas-delayed but easy-to-rack 9x19mm pistols).

  9. They are releasing a MkII R51 apparently Euroweasel, it made an appearance at Shot show 2015 I read on TFB. It’s going to be made in a different factory, as Remington have moved production facilities. And it’s got a new magazine base plate, some “coating” on the working parts, an improved trigger amongst other things as so reported. The suggestion was it’s fixed, and the problems were as initially claimed due to mass production errors presumably apart from the improved design aspects aforesaid. Sometime mid summer I think is the re-release date now, rather than October just gone. Might have fixed it, who knows maybe they just rushed it.

  10. The problem with the R51 is that most potential buyers and early adopters were turned off by the disastrous release of the initial model. Remington burned up a lot of good will with that mess. I used to like Remington, but am now skeptical about anything they’ve produced recently. I’ve had good results from the Beretta Nano in that size class, and with Glock’s likely release of a single-stack 9mm compact, I think the new and “improved” R51 will probably be dead in the water.

    • That Walther Euroweasel mentioned is in a similar price range also apparently Doc, and it’s a “tubby’ish” single stack. Remington definitely should have really tried to ensure the R51 wasn’t a flop via functioning problems, rushed it seemingly particularly as now there’s immediate competition from Glock etc.

  11. Out of curiosity, does anyone know why the spring-over-barrel configuration has fallen out of favor lately (ie the last century or so)? Are there any significant drawbacks to the design?

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