Slow Motion: .32ACP Baby Luger Malfunctions

Mike Krause of San Mateo, California makes some gorgeous reproduction Luger pistols, including copies of the extremely rare .32ACP “baby” Lugers. Unfortunately, we didn’t have much luck with this particular one on the range. Still, I figured it would be of some interest to watch a couple malfunctions happening in slow motion.

31 Comments

  1. Ian, since switching to Windows 10, your videos will not play. Don’t know what the issue is. Seems to only affect your videos. 🙁

  2. Luger’s breeechbolt backward travel distance is too short for reliable feeding and it is remedied by more powerfull magazine springs to catch the speed of action cycling. This pistol seems a faithfull copy of original short recoil sample using some of backward breechbolt travel for unlocking action and suffers same feeding problems of its big brother. Using; more powerfull magazine spring, spring forced ejector(İf locatable) or a special temporary breechbolt( if practically designable) may be the approaches to overcome the situation.

    • Actions that use a slide that stops after a short distance, and a light bolt that continues

      Like the luger, the Mauser C96, the Lahti, and the early automag

      Must rely on high speed movement of the bolt, in order for it to carry sufficient energy and momentum to complete the operating cycle reliably, especially if conditions are less than optimal, with cold, dirt etc.

      In the Mauser, this is achieved by fast unlocking and high residual breech pressure.

      The luger, Lahti and early, schwarzlose like automag all use accelerators to transfer energy from the slide to speeding the bolt. This is implicit in the breaking of a toggle in the luger, and a separate explicit part in the others.

      A direct result of this light fast moving bolt, when compared to the heavy and slower moving combined slide and bolt in Browning type pistols, is the very short window of opportunity for the mag spring to raise the cartridge column sufficiently to place the top round into the correct position for feeding.

      Hence heavy mag springs in the Luger, and brutally heavy mag springs in a Lahti.

      What this also does is to narrow the range of loadings for safe and reliable operation.

      I suspect that the. 380 luger is optimised for heavier loads, on the basis that optimisation for lighter loads would leave it vulnerable to getting hammered to pieces by heavier loads.

      Where optimisation for heavy loads, should have it operating sweetly.

      To an ordinary user, failure to operate is obvious and quickly corrected, where over speed operation and accelerated Wear are not necessarily apparent, until something breaks. At that point, reputational damage is applied to the pistol, not the owner.

      • By cause of the longevity of short recoil distance, extraction of empty case in Luger is carried out nearly solely gained momentum instead of plus aid of residual gas pressure on other same class of pistols. Toggle acceleration through leverage, by means of momentum converting, also decelerates the backward recoiling speed of barrel extention resulting to get an overspeed for breechbolt rearward travel. Though this is useful for the breechbolt to complete its cycling mission, it also provides a higher returning speed for the same by cause of crowded and narrow space at back of pistol occupied by the rear toggle joint lessening the its travel path, and if the magazine spring has no ability to response that speed, returning breechbolt overrides the top cartridge in the magazine instead of pushing it into the chamber. Besides, since the Luger ejector being a fixed one adjusted for full lenght of the round it uses, the empty case waits its stroke as engaged by extractor hook alongside the full backward travel of breechbolt. This may cause a malfunction through enviorement terms. A spring forced ejector would make the same job better. IMHO.

  3. The old Erma KGP and Stoeger “Luger” toggle-action blowbacks didn’t work too reliably, either, in calibers from .22LR on up to .380 ACP.

    I suspect the main reason is that the Maxim/Borchardt/Luger “toggle lock” requires a considerable amount of force to “break” it loose. The P.08, for instance, works best with loads generating 350-375 FPE; think a 124 grain bullet at 1130 F/S or a 115-grain at 1170, minimum. No, most commercial 9 x 19mm today isn’t that emphatic.

    Bullet profile is important, as well; the Parabellum design likes a long-ogive FMJ or a truncated-conical one with a very small meplat. Round OAL is critical; most modern ammunition simply isn’t long enough to avoid ramming the bullet nose into the feed ramp.

    Extraction/ejection problems in .32 may simply be due to the available energy budget vs. the requirements of the toggle system. That is, there may be enough energy to extract, but not enough left over to recoil the toggle far enough to eject cleanly and feed reliably, hence the “smokestack” jam.

    Most experiments with different chamberings in the Parabellum design seem to have problems with any cartridge and loading which strays too far from the profiles and power levels of the 7.65 and 9mm Parabellum rounds. For instance, the U.S. .45 Test Articles.

    Myself, I’ve always thought a Parabellum in 7.63 x 25mm Mauser would be highly interesting. But I have my doubts about its feed reliability.

    cheers

    eon

    • “No, most commercial 9 x 19mm today isn’t that emphatic.”
      Why? I know that not military cartridge can vary in power, but shouldn’t be this in both sides (lower and higher).

      “Parabellum in 7.63 x 25mm Mauser”
      It is feasible considering the overall cartridge length (29.69mm for 9×19 and 35mm for 7.63×25 Mauser)

      “Maxim/Borchardt/Luger “toggle lock” requires a considerable amount of force to “break” it loose”
      Maxim machine gun was produced in various cartridges version, not only rifle-size but even cannon size – Royal Navy QF 1-pdr more commonly known as pom-pom. So it should can be also scalable for smaller cartridge, or not?

      • Once you get to the very low end of the caliber/energy spectrum, the mass of the breech-locking system itself becomes a major factor relative to the available energy (i.e., recoil force) which actually “powers” the mechanism. Not to mention the exact geometry of the toggle movement, which can increase or decrease bolt “dwell time” ,more than you might think.

        A 37mm (1-pounder)operated at a breech pressure of 20,000 PSI. Due to the size of its case head (.75in R x 3.14\2), the “working pressure” on the breech face was some 94,000 pounds. This is more than enough “thrust” to operate the toggle bolt reliably, vs. its mass of (IIRC) 5.5 lbs.

        The .303in cartridge (MK V through VII) intended for the SMLE rifles had an operating pressure of roughly 39,000 PSI. This was found to be insufficient to operate the Vickers-Maxim MG’s action reliably, as well as not generating sufficient range for long-range interdiction fire. The result was the MK VIII and VIIIZ ball, with a heavier boat-tail bullet and an increased OP of 42,000 PSI (MK VIII) and 60,000 PSI (MK VIIIZ). Both operated the Vickers-Maxim action reliably, with its 1.7 lb bolt toggle system. The working pressures on the bolt face would be (case head dia. .530 in);

        MK VII; 34,400 PSI

        MK VIII; 37,000 PSI

        MK VIIIZ; 52,900 PSI

        Moving on to the 9 x 19mm, SAAMI pressure for standard 9mm is 35,000 PSI (piezo). That for the .32 ACP is 24,000 PSI (piezo) maximum. Anything above either figure is considered “+P” for the respective cartridge.

        The bolt thrust on a 9 x 19mm Parabellum is therefore ~4240 lbs. That of a .32 ACP is ~ 6672 lbs.

        Allowing for bolt/toggle masses of under 9 ounces in each case, and remembering that standard-velocity 9mm is borderline in the Parabellum action in terms of function, we see that the .32 ACP, while probably working a lighter bolt, most likely still doesn’t have quite enough “oomph” to reliably move that toggle all the way up and back with every shot.

        At a SWAG, the bolt thrust on a standard 9mm-diameter Parabellum bolt face to ensure reliable function would have to be on the order of 7000 lbs. This works out to a breech pressure (piezo) of about 60,000 PSI, 25,000 PSI above SAAMI maximum. If that isn’t “+P”, I don’t know what you’d call it.

        (I’d call it “insanely dangerous to even try”. I tell you three times; DO NOT ATTEMPT A HANDLOAD AT THIS LEVEL! NEVER! NADA! PERIOD! FUGGEDABOUTIT!!!)

        You can fiddle with springs all you want. But toggle geometry seems to be the major factor, plus bolt mass.

        The .32 ACP “Baby Luger” is very rare. I suspect that reliability (or lack of same) is probably why it never caught on.

        /just a guess.

        cheers

        eon

        • If memory serves up through at least WW2, British psi values were obtained from bolt thrust copper crush pins. The U.S. used a port on the side of the chamber for the pressure delineation.

    • The .32 ACP may be too weak to cycle the action properly, but let’s not forget the 7.65mm Parabellum cartridge was not as hot as 9x19mm (old or modern). The original DWM load launched a 93 grain bullet at 1215 fps (305 ft·lbf) and it obviously worked fine. The modern Fiocchi factory load is listed as 1198 fps with the same bullet weight, and it also works just fine. Not surprisingly, since most still used 7.65 Parabellum pistols are Lugers (or Parabellums as usually called in Europe) and the Fiocchi load is the only remaining factory option.

      • That’s what I use in my 7.65 Luger and it does all the things that his .32 is doing. It appears little used and is in great condition but just won’t cycle more than one or two rounds before a problem.

  4. Windows 10 is not a factor, viewing videos just fine. Love the slow mo of the stovepipe. One of my favs to clear in IA drills.

  5. I have a DWM 1920 7.62 luger that does the exact same things. I can’t get it to function reliably to save my life. My 1940 9mm luger runs like a top.

    Those are cool and while I never buy any modern guns that one could entice me if it were reliable.

  6. i can not state the specific ballistics, however by observation from shooting lots of 9 mm WW 2 German surplus and German WW1 surplus ammo when it was readily available, the WW2 rounds seemed definitely “hotter” than the WW1 or the commercial ammo. The P08’s all, save those put together by Gi’s from parts bins, ran like tops with the WW2 German surplus ammo, even the steel cased lots. The WW1 German surplus did not seem as “hot” , possibly because of its use in the red 9 C96’s. But that said, the WW1 surplus German 9mm had a truncated cone slug that fed as smooth as silk in any good P08 much less the 9mm C96’s. Those p)8’s that ran well with the German surplus, would occasionally have trouble with loading and extraction with the commercially available ammo. Good quality handloads seemed approximate with the WW2 german surplus in performance. However, these are general observations without definite, objective data.

    • If the WW2 ammo was steel-cased “480c”- code, that was a 124-grain bullet loaded to generate a MV of 500 m/s (1640 f/s) from the 9.75 inch (24.8cm) barrel of the MP38/40 SMG. It was intended to penetrate light armor (like the side of a U.S. M2 or M3 half-track) at 100 meters. And according to my uncles who were in the ETO, it absolutely would do just that.

      In short, it would be a “+P+” load by modern standards, being considerably “hotter” than most .357 Magnum 125-grain loads of today.

      I’m not too surprised that it worked a P.08 like a charm. I wouldn’t want to put it on any other 9 x 19mm handgun, though.

      I suspect it would be a bit much even for a P-35 High Power to digest. Let alone a S&W, Beretta, or Walther P38.

      I don’t like to think about what a steady diet of it would do to a modern polymer-framed pistol.

      Ouch. At both ends.

      cheers

      eon

      • Yikes. That last case would be one broken pistol and one obviously deader-than-dead idiot who thought 9×19 was wimpy. I can’t say if “hotter” ammo would solve the Baby Luger’s problem more than just redoing the springs and the barrel.

      • Amazingly, I never saw a decent P08 or P38 that did not digest the WW2 German ammo and all without spontaneously disassembling cracking. In shooting a Colt 1911 38 Super with commercial UMC against the P08 with good surplus I found little or no noticeable difference in the field. The WW1 lots were not as potent but I sure loved the truncated cone slug shape.

      • The Russian GSh-18, Strike One and others designed to fire the 7N31 armor piercing rounds probably could take the that ammo without too much problems. It is probably somewhat more energetic than the 7N31 (558 ft·lbf / 756 J) even from a pistol length barrel, but I would imagine the Russian pistol have some safety margin.

      • P35 would digest SMG fodder, but probably at the cost of reduced life.

        I’ve seen a p08 with a badly bent toggle from surplus Czech SMG ammo. I wasn’t present when it happened, but gather that it went full auto in the process. Haven’t given much though to the mechanism involved, if that is true.

        I’ve likewise seen a Lahti l35 that blew its bolt out the back, and a P38 with a broken slide side rail from the same cause. Good guns ruined with cheapskate ammo, the stuff had rusty steel jackets and corrosive primers too, yuk!

        • The weakness of the Lahti L-35 was discovered already during WW2. Lahti designed the pistol to fire mild subsonic loads (124 grains @ 950 fps, similar to 9mm Glisenti), which were the standard pre-war 9mm pistol ammunition of the Finnish Army. However, already during the Winter War it was realized that it would not make sense to manufacture separate 9mm SMG and pistol ammunition with the limited resources available, and after the small pre-war pistol ammo stocks ran out, SMG ammo was used in the pistols.

          The Finnish SMG load was actually not super-hot, 124 grains only about 1300 fps from the 12.4″ barrel of the Suomi SMG, which is similar to modern +P loads. Nevertheless, cracks started to appear in the bolt of the L-35 sometimes after as few as 200 SMG rounds were fired. Catastrophic failure did not follow very fast after that, so usually the bolts could be replaced in time, but clearly the design was much too weak for a steady diet of the SMG ammunition. Still, nothing was done fix the issue, because it was considered a secondary. Even after the war the SMG ammunition continued to be used with the bolts repaired by armorers as necessary.

          So, if you have a Lahti L-35, only fire mild target loads. Even standard pressure loads close to the SAAMI or CIP maximum pressures may be too hot if fired in the thousands.

        • The WW 2 German rounds that I spoke of were all pristine and right out of the cans. It would be interesting if anyone has any actual German data on the long term effects on the P08 and P38. All the good P08’s ran like tops with it. Even the seemingly less powerful WW1 lots ran well but utilized a different bullet profile. The only WW 1 9mm rounds that I have fired were all brass cases. The WW 2 lots were both brass and steel varieties.

          • Remember, in the day, you could purchase them for less than a penny a round in can lots. Those were the days!

  7. If it is thought that the problem is a lack of power, a set of loading dies and a chronograph should answer that supposition in short order. Simply start with a chronograph of the offending ammo to establish a base-line and increase the charge by 0.1 grain each “step,” whole examining the cases for signs of over-pressurization, until a reliable round is established. Then load a bunch to run an extended test of the weapon while keeping VERY careful notes. Then post the results for validation purposes. Meanwhile, explain to Wife that you are conducting “Serious Scientific Research” that will in all probability require additional (expensive) equipment. Works in my house every time …

    • Be sure to find a way to keep yourself from going deaf at the same time.

      Weapon of choice scenario:

      Alone in the deep dark woods, after having experienced an engine failure in your car, you contemplate braving the rainstorm and going towards the nearest sign of civilization. In the back seat is your luggage, a Baby Luger foisted upon you by a friend, and a surplus M1917 revolver. I’m also with you at the moment and I’m letting you take stuff from my buried stash of “war trophies” near the conveniently placed oak tree if one of us is to guard the incapacitated vehicle from highway robbers.

      If you’re going to seek help, take a weapon from this first list:

      1. Colt M1911
      2. Winchester Model 1907
      3. Russian Nagant Revolver (and optional suppressor)
      4. Spanish El Tigre rifle or Destroyer Carbine
      5. M1 Garand
      6. Sturmgewehr-44
      7. Get your favorite toy and get out there before midnight!!!

      If you want to guard the car, try this list:

      1. Hotchkiss M1926
      2. Lewis gun
      3. Lebel Rifle with ludicrously intense tactical flashlight
      4. M1897 Winchester trench gun
      5. Danuvia 39M and Danuvia 43M
      6. M712 Schnellfeuer
      7. Steyr-Solothurn MP-34 (o)
      8. Add your favorite toys to this list!

      I hope you’re not afraid of the dark…

      This activity is a voluntary item. You are not required to participate if you do not wish to do so. Please keep any and all criticism of this post humane and free of foul language.

      Thank you,

      Cherndog

  8. “Ian, since switching to Windows 10, your videos will not play”

    windows 10 = big shit 🙁

    linux faster, safer, free ect…

    • Linux also asks for your permission before it does things, unlike certain other operating systems that have less respect for you and your boundaries.

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