H&K’s Hydrocephalic P7M10 in .40 S&W

Everyone has an off day eventually, and for H&K one of those off days took the form of the P7M10. Introduced in 1991, the M10 was based on the frame and magazine body of the double-stack P7M13, with a .40 caliber barrel and a substantially increased slide mass. This extra mass was deemed necessary by Oberndorf engineers to safely handle the .40 S&W cartridge, although this was not a universally shared determination. In addition to slowing the opening of the slide, this extra mass substantially handicapped the pistol’s handling, making it top-heavy and bulky.

The effort had been aimed at law enforcement sales, for whom the .40 was a very popular cartridge at the time. The poor handling and looks of the gun prevented any major agency sales, and the gun was taken out of production in 1994 when the AWB passed. The ban prohibited importation of the P7M13, and while the M10 had legally-acceptable 10-round magazines, it was clearly a poor seller and was based not he M13 production infrastructure. With the M13 removed from manufacture, the M10 no longer made sense to build. Enough remained in inventory to list in H&K’s 1995 catalog, but they were gone by 1996. The P7M10 is a scarce and collectible gun among a niche group today, simply because of its small production numbers.

Thanks to H&K for letting me film in the Grey Room for you!

43 Comments

  1. The video says: …”to safely operate with higher pressure of the 40SW cartridge”…(С)
    The pressure of 9×19 and 40SW is almost the same. At 40SW, the recoil impulse is greater than 9×19.
    And since the pressure is the same, the gas brake does not work effectively enough.
    By adding mass to the slide, they slightly reduced the rollback speed. But it remains to balance on the brink. High chance of a broken case.
    And in addition, poor ergonomics due to strong rollover when fired.
    Another stupid attempt to make two fur coats from one skin.
    In the sense, to shove too powerful a cartridge into the system, originally designed for much less power.
    Stillborn.

    • There’s a lot more subtlety to cartridge design than a lot of folks realize, which goes into the way the cartridges interact with the weapons firing them. A lot of the time, the really “good” cartridge/weapon combinations happen less by design than by sheer happenstance.

      The .40 S&W is a cartridge that’s failed because of these factors; there’s the pressure curve it develops, which comes from the shape of the case, the burn rate of the powder, the size of the primer, and how it propagates the the deflagration wave through the powder. In the case of the .40, all that combines to make a snappy, hard-to-control cartridge that beats the ever-loving hell out of most of the 9mm pistols that were converted over to fire it. Generally, purpose-built .40 pistols have done a lot better, because the lock work was timed properly and all the other factors of the mechanism were designed around it from the beginning.

      There are reasons that a lot of cartridge conversions don’t work very, and it boils down to these factors. A typical weapon/cartridge combo will be designed to work together, and some mechanisms simply aren’t appropriate for some cartridges. I’d submit that the roller-delay system should have been left to cartridges in the same class as what they were initially designed around, namely the 7.92 Kurz. Higher pressure and bigger cartridges require a lot of complication to be added, like the chamber fluting. If you’ve got to do that, that’s a sign from Mother Nature that maybe, just maybe, this mechanism and this cartridge don’t suit each other very well.

      There is a hell of a lot more to all this than the average person thinks, and I’ve met serious gun enthusiasts who’ve spent years tweaking design characteristics to get things to work properly. There’s a tremendous amount of “weird” when you get down to it, like the guy I know who was into benchrest shooting, and who discovered that a specific powder/primer/bullet combination would drop his group size down into the fraction of an inch range, yet in another presumably identical rifle, that same handload wouldn’t group at anything under three or four inches. Go figure that one out, because nobody who ever looked at that set of rifles and handloads ever did. Only thing we could figure out was there was some oddity in the barrel harmonics or something–The rifles were exactly identical, consecutive serial numbers he bought for his kids to use in their matches, but one grouped in better than spec with the handloads he tuned for it, and the other flatly would not ever do better than 3-4 inches with anything he tried in it. Nobody could ever come up with an explanation for it–Both barrels gauged exactly the same, both came off the same line using the same reams and everything else. He put it to the factory, and they were really bemused by the whole thing. It wasn’t like one barrel was from brand-new machining and the other was from worn, either–They were both from about the same point in the tooling lifespan.

      • The 10mm Auto cartridge (originally the .40 G&A) was a case in point. Originally designed for a rebarreled M1911, the first attempt to build a pistol around it was the Bren Ten, a modified CZ75.

        It proved to be simply too small to accommodate the long 10mm round; several examples would extract the fired case and shove it back down into the top of the magazine and then close on an empty chamber, due to insufficient clearance for the case to cleanly leave the ejector port.

        S&W and Colt both built 10mm autos on .45 ACP sized platforms, the S&W 1006 and Colt Delta Elite. They quickly learned that the increased slide velocity of the 10mm resulted in the frames taking a severe beating.

        The one autopistol that seemed to work correctly with the 10mm was the Glock 20. And it was designed literally from a blank sheet of paper, rather than being simply an enlarged Glock 17. It used extra slide mass to retard the operating cycle. My experience with it was that it was accurate and reliable, but it really only functioned well with Norma or Winchester 10mm Auto which were full-power loads approximating .357 Magnum to .41 Magnum performance. With the “medium-velocity” aka “FBI 10” loads, which were basically 185-grain .45 ACP match loads in the 10mm case with a 180 grain bullet, reliability and accuracy both were degraded.

        The only really successful 10mm Auto handgun, capable of dealing with the peculiarities of almost all 10mm factory loads, was the S&W 610 DA revolver on the N frame. And if you were going that route, you might as well get a 657 .41 Magnum or a Model 28 .357, so you didn’t have to fiddle around with “moon clips”.

        The best 10mm pistol than never was, IMHO, would have been a Ruger Blackhawk convertible in .38-40 WCF with a spare .40 S&W cylinder. All it would have needed was a third cylinder in 10mm Auto, and you’d have the best of all worlds in .40 caliber bore size.

        The 10mm automatic cartridge is an interesting idea that’s been around for over a century; see 9.8mm Browning/ACP, circa 1910.

        It’s also one that so far, nobody has ever managed to get right.

        cheers

        eon

        • “(…)The 10mm Auto cartridge (originally the .40 G&A) was a case in point. Originally designed for a rebarreled M1911, the first attempt to build a pistol around it was the Bren Ten, a modified CZ75. (…)”
          Bit later IMI started to offed Jericho 941
          https://modernfirearms.net/en/handguns/handguns-en/israel-semi-automatic-pistols/jericho-941-eng/
          it was designed to allow easy replacement of parts to get either 9×19 mm Parabellum chambered weapon or .41 Action Express chambered weapon (thus 941 in name). Second cartridge aimed for similar role as .40 S&W, but never get similar popularity – despite being not inferior to .40 S&W and 941 being solid performer if I am not mistaken.

  2. “(…)The ban prohibited importation of the P7M13, and while the M10 had legally-acceptable 10-round magazines, it was clearly a poor seller and was based not he M13 production infrastructure.(…)”
    Wait, this mean that sales were so poor than they decided to remove it from offer, even after other over-10-capacity automatic pistols were ruled out of market.

    • What did you expect? If the handling and performance of the system is bad overall, it will not matter how many cartridges can be held in the magazine.

  3. It sounds like the gas delay mechanism couldn’t cope with the extra gas from the .40 caliber. The spring rate and mass of the slide can be scaled for the change in caliber, but once the gas delay chamber is full the rest of the gas goes out the muzzle. Give or take the pressure curve and bullet velocities.

  4. “…the really “good” cartridge/weapon combinations happen less by design than by sheer happenstance…”(C)

    This is called “the scientific poke method”. 🙂
    So almost all successful cartridges are designed. First, the ammunition parameters that are optimal for the tasks are determined, and then they are adjusted along with the weapons “drop by drop” to optimize the characteristics.

    And in the situation “we must catch the gun show”, such scumbags necessarily appear.

    • Reminds me a bit of what I’ve read on the development of the first .500 Nitro Express rifle. It was easy enough to take a .500 3″ Express black-powder round and switch to cordite propellant, but getting the combination of steel and profile right for a barrel to survive firing it? That took some work. As I recall they blew out half a dozen barrels (which, given this was about 1890 and they were working with double rifle barrel sets, was not an insignificant investment) before getting something heavy enough to survive proofing.

  5. Kirk’s comment is spot on.

    It doesn’t matter much on manually operated firearms (though even there it may cause problems, eg with feeding on bolt-action rifles) but once you start changing the cartridge on semi or selective-fire things, you are cruising for trouble if you don’t do a detailed re-engineering of the whole system. The changes may individually be small, but collectively the difference between failure and success.

    Most of the early 40s based on 9mm designs were poor. Slide velocities too high, breeches that unlocked a tad too fast. It all made for a less pleasant shooting experience, and more muzzle flip than there should have been. And often mediocre accuracy. Especially marked in more compact models. A lot of the early 40s needed redesigning internally to get them to work well. Manufacturers tried to do the redesign on the cheap (new barrel, mag, stiffer spring, and as few other changes as possible) and it often didn’t work very well.

    The Glock 23 was/is one of the better smaller 40s, but even it, especially in early models, had the same issues. Shoot a G23 with standard 40 against a 19 with +P 9×19. Very similar amounts of muzzle energy, but the 19 is markedly more controlllable and accurate.

    41AE illustrates Kirk’s points. At one level, a great idea. Just swap the barrel, recoil spring and mag in your 9mm and make it “better”. In practice, it had the same issues described above, compounded by feeding issues due to the rebated rim. So you’d spend a couple of hundred 1980s dollars turning your perfectly decent 9 into a less reliable and harder-kicking 10.

  6. The above fully applies to this pistol and cartridge. The 40SW cartridge was designed to cross the road 41AE, which is noticeably better in a number of ways.
    In the case of 41AE, the developer took too long with that optimization.
    Also, the manufacturer (then IMI) set such a sale price that people only shrugged their shoulders …

    But the SW “on the gun show” managed.
    And now we see exploding Glocks …

    • Way too much emphasis on punching power was the problem. Given a choice between any high capacity 40-SW handgun and the original nine-shot Ruby in 7.65 Browning, I’m more inclined to use the latter in a dark alley scuffle. I could be wrong…

      • Not really. The .40 S&W was designed in pursuit of the yearned-for “one-shot stop”. The trouble is, there really is no way to define what that is.

        Is it when the assailant stops moving?

        Is it when he stops attacking?

        Is it when he theatrically stops, drops his weapon, clutches his chest where the bullet hits him, groans, and falls to his knees?

        Or is it when he hits the ground, not breathing, deader than the proverbial mackerel?

        The answer is…no two “experts” ever agreed on what constituted a “one-shot stop”. Whether you’re talking Hatcher, Cooper, Fackler, Fuller, or Marshall & Sanow, they all had different definitions.

        It’s interesting to note that one of the few “one-shot stops” on record is in the book Shooting to Live by W.E. Fairbairn and Eric Sykes, written in 1941 and based on their experiences as training officers with the Shanghai Municipal Police a decade earlier. One of their officers shot a buhau doy (tong “soldier”) center chest during an altercation on the docks one night, causing said fellow to fall down and die in about two seconds flat. The bullet had gone right through his heart and basically hit the center nerve junction, causing it to stop beating.

        The weapon? A Colt Model 1903 Pocket Model, .32 ACP, firing the then-standard 71-grain full-metal-jacket round nose at about 800 F/S for just about exactly 100 FPE.

        Fairbairn and Sykes considered it a fluke. In their opinion, the job of an officer (or legally-armed civilian) in a “gunfight” was to shoot the adversary as many times as possible in the shortest possible time, always aiming for the vitals or the head. They stated that a service or defensive sidearm should resemble, or simulate, a machine gun as closely as possible.

        As you might expect, when both were teaching Commandos and the OSS how to “fight dirty” during WW2, they found the FN M1935 High Power in 9mm much to their liking. They did not consider the M1911 .45 ACP to be a better “manstopper” than the 9mm HP; they considered that either one would get the job done, but the P35 held more ammunition.

        As Ian related, the Commonwealth forces during WW2 preferred revolvers, but fell into using the P35 9mm automatic rather by accident when a large order of same made for China by the John Inglis company in Canada couldn’t be delivered. I’ve often wondered how much influence Fairbairn asd Sykes had on that Chinese order being placed to begin with.

        So no, preferring even a .32 ACP over a .40 caliber plus “wonder cartridge” isn’t a mistake. The mistake is thinking that it should only take one hit to get the job done.

        Or as my mother taught me as a child, the signal to “cease fire” is when the target is flat on the ground and preferably no longer breathing.

        cheers

        eon

          • It has about the same muzzle velocity as the .380 ACP but a smaller diameter bullet. This tends to result in more penetration.

            The .32 has always been noted as a deep-penetrating little bugger for its size. As such, it tends to get well into the vitals, even through strap muscle or bone. Which is what you want in a defensive pistol round.

            Only hits count, and only ones that get inside the workings get the job done.

            cheers

            eon

  7. .40″ cartridge is approximately 1/3 heavier than the 9mm parabellum. This means, for an ensured free blowback distance when the highest gas pressure in the barel, it needs same level heavier bolt for .40″ round compared to the 9mm through the same lenght of barrel. Keeping in mind that the gas brake is provided for slowing the bolt full backward travel, the function of bolt mass and gas brake become evident; mass for keeping the barrel’s back at highest gas pressure exists, gas brake for slowing the bolt’s full recoil for quicker target recovery for follow up shots and prevent tiring both the gun and shooter.

    • lf the user can manage the recoil punch which being still in ensured free blowback at instant of highest pressure within the barrel exists, the slide weight could be lowered. The best free blowback travel for this purpose is computed as 2 milimeters for all barrel lenghts. This value is related by the thickness of the web at back of the cartridge case. But in practice, the ensured free travel is applied as 3- 3,5 milimeters which being still in the safe limit and it might be even lowered further by experience and first batch of .40″ caliber production should be made with this thought in mind. lMHO.

  8. 3-3.5mm, if no additional measures are taken (like Revelli) mean a guaranteed break in the case.
    And the grooves in the chamber do not guarantee anything. Separation of cases happen even on MP5.

  9. Do not know if case material is different but, l have seen empty cases over deformed like a reversed bottle fired from a MP5 that rollers of which is taken out, hand made 9mm fixed barrel pistols with ejecting nearly non deformed cases and seen no case seperated factory loaded cartridge case fired from a pistol sized gun.

    l do not remember the exact weight of the pistol slides like Astra, Llama and some other simple blowback handguns but when scaled, it would be easily seen that their masses remain in minus side of 2mm ensured free blowback distance.

    Again, lock and delay devices for pistol size guns are thought for; shooting comfort, quick target recovery with follow up shots, maximum using life of guns and providing targeted performance for the used cartridge.

    lMHO.

    • Possibility of seeing a case seperation in a properly working pistol caliber guns is nearly impossible but, an improperly working so kind of a gun may demonstrate similar happenings mostly by cause of “Battery Off” firing occured through faulty chambers, firing, disconnecting members… Not by insufficient bolt mass, lock or delaying devices… lMHO.

    • Remington seems a result of “Battery Off” firing and HK looks a fauly case with over pressed bullet seat crimp.

      This kind of scarce events can not be accepted as rules and their causes should be deeply resarched. Persons are not limited at their thoughts however. IMHO…

  10. “…I could be wrong…”(C)
    Everyone can be wrong …
    But not in this case. 🙂

    For a precisely fired bullet, a 1mm diameter difference does not make a fundamental difference.
    Until the end of MV2, many countries considered 8mm quite sufficient even for army use. Although everyone noted that “9mm hits harder than 8mm.”
    But it does matter when the hit is “out of place”, then a larger bullet (especially expansive) is more likely to catch what is needed. Not to mention a bigger surge.
    The second side of the coin, a solid 8mm bullet (like .32 or the like), in addition to leaving a good shooter with more rounds, makes it possible to control the severity of the injury. That is, when fired, say, in the leg, it will not be amputation, but simply a hole.

    • “9mm hits harder than 8mm”

      Only because generally the 9mms were going faster. Most of the 8mms were in the same ballistic class as the .32 S&W of 1878 or the .32 S&W Long of 1896, firing an 85 to 95 grain bullet at roughly 750 F/S for about 110 FPE.

      The early 9mm automatic pistol cartridges fired somewhat heavier (120 to 130 grain) bullets at significantly higher velocities (around 1,000 to 1,100 F/S) for substantially greater kinetic energies (from 300 to 350 FPE).

      It’s worth noting that in standard WW2 service loadings, the .45 ACP (230-grain FMJ at 850 F/S), 9 x 19mm (124-grain FMJ at 1,150 F/S) and 7.62 x 25mm (87-grain at 1,350 F/S) all have roughly 350 to 370 FPE muzzle energy.

      The 7.62 has greater penetration, the .45 may have a greater “psychological effect” due to the size of its muzzle. In terms of killing power, all three deliver about the same amount of kinetic energy to the target, and statistically, all three get about the same results.

      Having used all three over the years, in my experience the 9mm is the most user-friendly. It’s not as loud as the 7.62 and generally holds more rounds than the .45.

      If the U.S. Army had adopted the 9 x 19mm in 1911, there would have been a lot less nonsense written about “stopping power” over the next eighty-odd years.

      cheers

      eon

    • “For a precisely fired bullet, a 1mm diameter difference does not make a fundamental difference.
      Until the end of MV2, many countries considered 8mm quite sufficient even for army use. Although everyone noted that “9mm hits harder than 8mm.” “

      Au contraire, my friend. Intrinsically that 1mm may not mean much to you, but it means a hell of a lot to the cross-section of the projectile and its weight. An 8mm projectile has a cross-section of 50mm, while a 9mm projectile’s cross-section is 63mm. This becomes important when we consider all the factors that go into a projectile’s characteristics and design–You can’t make an 8mm projectile as heavy for a given length as you can a 9mm, so the 9mm is always going to be able to deliver more energy to the target.

      To contradict many men’s girlfriends, size really does matter. In order to have the same amount of energy available in an 8mm projectile as you do a 9mm one, you have to drastically raise the length of the 8mm projectile and/or increase the velocity. And, then we get into the purely mechanical issues that come with size–The bigger bullets are much easier to make lethal with expansion than the small ones, which quite often require a lot of contortions like the Winchester Silvertip .25 Auto that has a ball-bearing in the cavity.

      Also, it’s wishful thinking to imagine that anyone besides an Annie Oakley or a Jerry Miculek is going to be “shooting to wound” effectively, or that you can “control the severity of the injury”. Once the gods of random chance take charge of the internal ballistics in the target, there’s no telling what the hell that projectile is going to do. I’ve got an acquaintance who shot someone in the leg in a self-defense scenario, thinking that she was “…just going to discourage him…”. Yeah. She hit the femoral artery sweepstakes jackpot, and her “Just gonna wing him…” turned into “Let’s play Jackson Pollock with the bright arterial spurting…”. Dude was dead within about two minutes, and if she’d been dumb enough to talk to the police/DA without a lawyer, she’d have likely gone to prison for the “murder” because of her articulation that she was “…just gonna shoot him a little…”. That does not work, in the real world. If you think you’re going to calibrate your wounding, the legal effect of that is having to explain why the hell you fired at all in a situation where you didn’t “need” to embrace the virtues of full-on lethal force.

      Point is, legally? If you’re going to shoot someone, don’t shoot to wound. That opens up a lot of questions like “Well, did you really think you needed to do this…?”, which leads to lots of rich lawyers. You shoot to stop. You do not “shoot to discourage”, because an awful lot of things can go sideways. If the bastard needs shooting, you shoot them until they stop doing what they’re doing, and that means basically that you’re trying to kill them as expeditiously as possible, or you’re gonna wind up in a bunch of trouble for using a firearm when you didn’t really need to, which is what your articulation of “I was shooting to wound him…” means in lawyer-speak.

      Or, so the lawyers I’ve been taught by have told me. I am not a lawyer, this is not legal advice, and we’re on the internet. Use this information and advice accordingly, and I highly advise seeking out a lawyer or classes on these issues if you’re carrying a firearm for self-defense.

      • IMHO, the obsession with “cross-sectional area” is another manifestation of the hoary “stopping power” debate. Hatcher was the first to bring it up (see Hatcher’s Notebook, available free online several places). Cooper expanded on it, as did Josserand & Stevenson in the early 1970s.

        What none of them figured out (or admitted) was that given equal kinetic energy, the larger-diameter bullet is going to have less penetration.

        This may or may not be a good thing, depending on the situation. The FBI Relative Incapacitation Index favorite, the 147-grain subsonic 9 x 19mm hollowpoint, was noted for overpenetration in police service use, because it (A) did not expand worth two cents at subsonic velocities and (B) therefore behaved almost exactly like the 158-grain RNL .38 Special standard velocity it closely resembled ballistically.

        In a local example here in OH, back in 1989-90 Columbus PD used the 147-gr. subsonic in their new S&W automatics, while Franklin Co. Sheriff’s department used the Federal 124-grain JHP in their new Glock automatics. Due to Columbus/Franklin Co. being basically “Chicago East”, both had plenty of opportunities to observe the results “on the street”.

        After one year and several lawsuits due to overpenetration resulting in injuries to bystanders, CPD switched to the 124 grain JHP, full supersonic velocity. Mostly because with a roughly equal number of officer-involved shooting incidents, FCSO had had exactly zero similar problems.

        The 124 grain consistently expanded to about .50 inch, penetrated about 10 inches or so, and stopped. This, BTW, was what the FBI using the Fuller Index claimed the 147-grain subsonic was supposed to do. It didn’t.

        Important note; the 147-grain 9mm was originally developed at the behest of the U.S. Navy’s SEAL teams. Because they wanted a subsonic 9mm load that would reliably operate the action of the Heckler & Koch MP5K compact SMG with the add-on sound suppressor. Why they didn’t just use the MP5SD with the permanent suppressor designed to reduce a standard supersonic velocity 9mm to below Mach 1 as it left the suppressor is one of life’s little mysteries.

        It ended up as a 147-grain because two previous versions, 135-grain and 142-grain, did not reliably cycle the SMG’s action.

        Cross-sectional area and bullet weight are somewhat related. More bullet weight at the same velocity=greater kinetic energy. This was the formula for greater power used in black-powder days, when the burning characteristics of that propellant sharply limited muzzle velocities, even in rifle-length barrels.

        The .45 ACP was Colt and U.S. Army Ordnance’s attempt to duplicate the killing power of the .45 Long Colt in a shorter case loaded with smokeless powder, that was more adaptable to a self-loading action. They ended up with a heavy, low-velocity round with the muzzle energy of a 9mm going about 200 F/S faster at the muzzle.

        Meanwhile, everybody else was just concentrating on making their 9mms and 7.63mms go even faster than that. In the end, they all finished up with about the same energy and the same results at the receiving end, with cross-sectional area basically counting for what Jack did in the loo.

        Reality set in in the United States in 1929, with the introduction of the .38 Super Colt auto round, with about 450 FPE vs. about 350 for the .45 ACP, just due to leaving the muzzle going about 450 F/S faster.

        The near-simultaneous introduction of the .38/44 High Speed in the S&W .38/44 revolvers (Outdoorsman and Heavy Duty) on the N frame should have been another clue. The 158-grain bullet delivered 430 FPE because it left the muzzle at almost exactly 1,100 F/S; the speed of sound.

        The debate should have been ended once and for all with the introduction of the .357 Magnum in 1935. 160 grain bullet at an average 1,400 F/S for ~ 700 FPE should have told everyone that velocity was what mattered because energy goes up by the square of same.

        Nevertheless, we still deal with beliefs in “cross-sectional area”, other than their inherent effect on projectile mass.

        The thing is, increasing mass is a less effective way of achieving higher energy that increasing velocity. Going back to the “failure” of the .38 Colt revolver in the Philippine Insurrection, they didn’t need to come up with a new .45 revolver, or a .45 automatic. They needed to get that .357 inch, 125-grain bullet going faster that 780 F/S. Another 300 F/S and their problems would have been solved.

        The First Rule of “Stopping Power” is the same as the First Rule of Traffic Safety;

        Speed Kills.

        cheers

        eon

  11. “…similar happenings mostly by cause of “Battery Off” firing occured through faulty chambers, firing, disconnecting members…”(С)

    Theoretically, yes.
    In practice, grooves can clog with soot or rust …
    And systems with a slowdown of the bolt by friction of the parts of the mechanism strongly depend on … friction. 🙂
    This means that a system that normally (albeit on the verge) works under the same conditions (cartridge power, liner material, grease, dust), if they change, if it continues to work, either starts to stutter, or it’s peddling.

    • Not eager to continue through uncertain comments but would not help myself mentioning; rusty chambers prevent fully seating a loaded round and soot in the grooves located at a place where occurs the highest and cleanest gas pressure with heat, seeming unusual.

  12. Energy and psychological effect are secondary.
    At least for the goats on which the cartridges were tested at the beginning of the last century. 🙂
    And the goats fell from 9 mm better than from 8 mm. And from .45 is better than anything else.
    But if you use the same cartridge for a pistol and a SMG in the army, then 9×19 is obviously optimal.
    If we exclude such stupidity as the use of a 9×19 cartridge as a PDW, and use a much more suitable 4.6×30, then 10mm(.40-.41) is optimal for an army pistol.

    • There was exactly one one shot stop in the original Army tests in 1910. A bullock went down in three seconds and was dead in five.

      It was shot with a 7.65mm Parabellum FMJ, that hit the aorta square on.

      I consider those tests to be about as scientifically reliable as the Strasbourg tests. I believe both were exercises in confirmation bias; everybody involved knew what they wanted to find beforehand, and they cherry-picked the data to get a result they liked.

      I believe in “stopping power” theories about as much as I believe in “anthropomorphic global warming” theories. That is to say, not very much.

      cheers

      eon

  13. “rusty chambers prevent fully seating a loaded round”(С)
    Rust do not interfere with anything.
    Especially if the barrel is rusted with a cartridge inside.
    As often happens with service weapons.

  14. “I believe both were exercises in confirmation bias; everybody involved knew what they wanted to find beforehand, and they cherry-picked the data to get a result they liked.
    I believe in “stopping power” theories about as much as I believe in “anthropomorphic global warming” theories. That is to say, not very much.”(C)

    In personal alternative reality, You can believe in anything.
    However, in objective reality, You can also BELIEVE. 😉
    But many generations of hunters have long established that for each animal there are some minimal quantitative characteristics of a wounding shell that provide (although not guarantee) a “clean” shot.
    If you are lucky enough to get acquainted with this incredibly secret information, you even have a chance to find tables with specific values ​​to whom and how much should be enough. LOL

    PS By the way. In MY reality, global warming is still present. There is such a mystical thing, called a thermometer. Watching him for the last forty years, I register a constant increase in temperature.
    Sincerely.

    • If you’re referring to the Taylor “Knock Out” Factor, I would only point out that I don’t see much difference in the terminal effects of a .460 Weatherby and a .577 NE, even though the Taylor formula rates the latter considerably higher.

      As for AGW, I notice that those who wax most fanatic about it are also the most fanatically opposed to nuclear and hydroelectric power. Holy Wind and Holy Sun may Save Our Souls, but they won’t keep the lights on at night.

      I prefer solutions to pseudo-religious, pseudo-Utopian crusades. And measurable kinetic-energy results to “theories”.

      Sincerely,

      eon

  15. “…Au contraire, my friend. Intrinsically that 1mm may not mean much to you, but it means a hell of a lot to the cross-section of the projectile and its weight…”(C)

    No contradictions.
    Read more carefully.
    If you do not take into account separation to small parts, then only one thing can force an object to instantly stop any action.
    This is an effect on the central nervous system that causes either loss of consciousness or rather serious disorientation. With any kind of rapid blood loss, and even complete cardiac arrest, the object can remain conscious from a few seconds to minutes.
    You can physically destroy some attachments of the brain or spinal cord for the desired effect, but you still have to get there …
    And finally, the most effective one is a stunning blow. Which is not even dangerous to health, almost guaranteed to disable almost anyone.
    It is only necessary to “plop” strong enough.
    And for this, parameters such as caliber, energy, etc., are individually useless.
    And to operate them separately, it’s the same as saying that “the whale is the strongest because it’s wet”.

    The main reason for the “confusion” around such a thing as “stopping action” is the lack of understanding of the essence of the process.
    And when a person does not understand something, but really wants to, he begins to try to FANTASY definitions and labels. Try to put everything on the shelves, and if it does not fit …
    So shove it. 😉

  16. “…Remington seems a result of “Battery Off” firing and HK looks a fauly case with over pressed bullet seat crimp.

    This kind of scarce events can not be accepted as rules and their causes should be deeply resarched. Persons are not limited at their thoughts however. IMHO…”(C)

    There was no “Battery Off”.
    This is exactly the situation with “some change in determining factors” in the system on the verge of working capacity.
    And it’s not like that “scarce events”. You might think that all MP5 users only dream of telling about their problems on the network. 😉
    Such situations are much more than many would like.
    A small selection from only one profile site.
    https://www.hkpro.com/forum/hk-nfa-talk/189990-mp5-40-case-separation.html
    https://www.hkpro.com/forum/hk-rookie-corner/471254-mp5-brass-has-fluting-marks.html
    https://www.hkpro.com/forum/hk-nfa-talk/211919-anything-other-than-perhaps-too-hot-load-cause-shell-case-pattern-9mm-mp5.html
    The reasons are somewhat different, but the result is one. Difficult extraction. In some cases, with separation of the case, in others without. But it is always a stoppage.

  17. “…I don’t see much difference in the terminal effects of a .460 Weatherby and a .577 NE”(C)

    Of course You do not see. And I do not see. And no one will see …
    In the same way as no one will see the difference in the severity of the defeat of two identical whales from getting into the scruff of Fat Man and Ivy Mike. 😉
    Any measurement and calculation technique is applicable only to its range of values. If we measure, say, a rat and a cat, both will be “shorter than a foot, but larger than an inch and heavier than an ounce, but lighter than a bucket of water.” But this hardly gives reason to argue that they are “almost identical”.

    And regarding the Taylor formula, IMHO is just one of the far-fetched cases when they try to measure something, for which dimension has not yet been invented. And also it is not clear what exactly they are going to measure.
    Especially when You consider that most of those who like to flaunt the “Taylor formula” forgot (if they even knew at one time) that this is applicable only for narrow-specific shooting conditions. And completely unsuitable for all other cases.

    The “classic hunting technique” is much more convenient. According to it, for a sure defeat of a living object, the mass of one ball bullet (at a speed of at least 200 m/s) should be about 1/5000 of the mass of the affected object. For a reliable defeat, at least two such bullets are needed. +/- 10-15% depending on the individual resistance of the object.

    Sincerely.

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