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9mm vs. .38 and case volume - what gives?

Discussion in 'Handguns: General Discussion' started by Bikeguy, Nov 24, 2004.

  1. Bikeguy

    Bikeguy Well-Known Member

    Why does 9mm out perform .38 (as far as velocity - not stopping power, penetration, etc. - that's another discussion)? It appears to me that a .38 round has more case volume - it's nearly twice as long. So what gives? Why is the .38 not loaded to velocities that surpass 9mm? Is it not possible for some reason?
  2. Brian Williams

    Brian Williams Moderator Emeritus

    9mm guns have been built to run at a higher pressure and 38 spec was designed during the tail end of black powder cartridge development and needed the larger case to get it to the velocities designed with black powder and with the development of smokeless powder and the capability of smokless being able to produce the necessary pressure with less the case has lots of room. Now since many guns were built in 38 spec with lower levels of heattreating, a full tilt and boogy 38 spec loads like a 38-44 load or +p will tend to either blow up a very good gun or even bulge it.
  3. Bikeguy

    Bikeguy Well-Known Member

    I see! So the cartridge itself is capable of a lot more, but the guns are not? Makes perfect sense in a strange way!
  4. stans

    stans Well-Known Member

    Yep, the 38 Special can be hot loaded to approach 357 Magnum ballistics, its the guns that can't handle it. The likes of Elmer Keith and some others made a habit of hot rodding 38 Special and 44 Special and that's what lead to the introduction of the magnums. Even if you do have plenty of 38 Special brass, don't load it hot, it is too easy for such hotly loaded ammo to find its way into an old 38 Special revolver and the results can be disastrous.
  5. Jim Watson

    Jim Watson Well-Known Member

    The .38 Special was introduced in 1899 (or 1902, depends on whose book you read) as a black powder cartridge. It was "special" because it shot a 158 grain bullet with 21 grains of black, as an improvement over the .38 Government/Long Colt which shot a 150 grain bullet and 18 grains of black.

    That is why the case is so long, to hold as much black powder as could be efficiently burned in a revolver.

    When they went to smokeless, they had to set the pressure limit low enough that the old guns could stand it. The guns are of somewhat better material now but are of the same old 1905 era design. I have read of IDPA competitors having to use .38 +P to make even a 125 power factor and wearing out a K-Smith .38 Special gun in a couple of years frequent practice and competition.
  6. 115grfmj

    115grfmj Well-Known Member

    .38 has greater potential than the 9mm....

    Current loadings for the .38 have to be loaded lighter to deal with the
    older models, as well as weaker .38 only guns. As you might have guessed
    the cartridge is capable of much more than the 9mm is (heavier rounds,
    more powder capacity, etc..) The problem is the only guns capable of maximizing its potential are those chambered in .357 mag. The .357 is
    hugely more potent, making the increased .38 almost moot. Moral of the
    story is if you want a more power buy the .357. If not be satisfied with
    the still very effective .38 :D
  7. JNewell

    JNewell Well-Known Member

    Yep, or to try to put it differently, .357 Magnum loads do not need the extra case capacity. S&W stretched the case as a safety measure to prevent folks firing what amounts to a hot .38 in guns that wouldn't take the pressure.

    Same deal with .44 Special and .44 Magnum.
  8. MoNsTeR

    MoNsTeR Well-Known Member

  9. Standing Wolf

    Standing Wolf Member in memoriam

    Yep. If you've got a strong enough gun, the .38 special can be hot-loaded well beyond normal .357 magnum pressure and velocity levels. I'd strongly recommend against it, to be sure, but I've known people who've done it.
  10. thatguy

    thatguy Well-Known Member

    Like others have said, the .38 Special is not loaded to full potential due to concerns about cheap and very old guns out there. My defense load for the .38 Special is a 125 JHP at 1250 FPS and it works fine in my J and K steel frame S&Ws. I have gone to 1400 FPS with a 110 JHP but these were shooting way low with fixed sight guns so not useful.

    The old factory Hi-Speed loads from the 1930s used a 158 lead at around 1300 FPS. These will batter a K frame but not blow it up.
  11. Roadkill

    Roadkill Well-Known Member

    I think I was using 5.5g of unique with 125g lrn 9mm, 140g lrn in .38, and 230g lrn .45 as an all around general shooter load. I would stuff the extra case volume in the .38 with styrofoam to keep the powder on the ignition end.

  12. Jim March

    Jim March Well-Known Member

    Yeah, there's a whole slew of leftover black-powder-era cartridges still in use (in the US at least) which have shells "too big" for what you get.

    It keeps the peak pressure down though...easier on both the gun and you.

    Think of it this way: say you've got a load for the old 45LC (dates to 1873) involving a 230grain JHP @ 850fps, and another for the 45ACP that nets you the very same external ballistics - same bullet, same speed. The 45LC will get there with something around 15,000psi (roughly - I'd have to look up a loading manual and it will vary by powder chosen) while the 45ACP will need about 21,000psi.

    In each case that's "peak pressure". The old LC will hold it's pressure at peak for longer. Graph it out on a curve, the ACP will "spike" more sharply while the LC's curve will look shorter but broader.

    This directly affects how the gun feels in your hand. The LC will feel like a "big steady push" where the ACP will have a bit more of a "sharp crack".


    For this same reason, one caliber I've got a lot of interest in is something called the "356GNR". It's a wildcat - you take basically any 357Mag gun and alter just the cylinder. The shells are 41Magnum necked down to 357. If you use it to get 357Magnum ballistics, you can do it with a lot less peak pressure, OR you can hot-rod it to where 158s are pushing past 1,800fps, at least in a strong gun (Ruger Blackhawk).

    The way to get there cheap is to score a 357Mag/9mm factory convertible and send the 9mm cylinder off to Gary Reeder or one of the other gunsmiths with a 356GNR chamber reamer. You can still shoot 357Mag/38spl in the "normal" cylinder.

    Case capacity matters :).
  13. Jim K

    Jim K Well-Known Member

    As JNewell mentioned, much of the reason for the case length of the .38 Special was not for powder capacity but for safety. The .38 Special was made about 1/10" longer than the old .38 Colt so it would not chamber in the older guns (though it would in some guns without chamber shoulders), then the .357 Magnum was made 1/10" longer than .38 Special for the same reason, then .357 Maximum was 1/10" longer than .357 Magnum, again for the same reason.

    A .38 Special +P+ load was made for police use as a political round for police who didn't want to be criticized for using the "nasty" .357 Magnum. Pressures and velocity were equivalent to the .357, and makers warned it was to be used only in revolvers chambered for the .357.

    Handloaders can boost .38 Special and .357 performance by taking advantage of the extra case capacity, but doing so demands both knowledge and care. Too many good guns have been destroyed by folks deciding that "if more powder is better, a lot more powder is better yet."

    The 9mm Parabellum, designed in the smokeless powder era, and with no "old" guns to be concerned about, could be, and was, loaded to take advantage of the capabilities of the (then) new powders.

  14. Jim Watson

    Jim Watson Well-Known Member

    Disagree, Jim K.
    As I said, the .38 Special was made longer than .38 Long Colt so as to hold more BLACK powder. Black powder is loaded to fill the case; more power takes more powder, takes a bigger cartridge.

    And not to be a nitpicker, I can tell the difference between 1/10", 1/8" and .135" which is the actual difference between .38 Special (1.155" case length) and .357 Magnum (1.290" case length) even though legions of shooters and writers have not been able to over the years. The Special is .120" longer than the .38 Long Colt (inside lubricated version) which is not 1/10", either.
  15. Standing Wolf

    Standing Wolf Member in memoriam

    Not so. Length of the .357 magnum is 1.29 inches. Length of the .357 maximum is 1.605 inches.
  16. Clean97GTI

    Clean97GTI Well-Known Member

    So, one could shoot a hotrodded .38 out of any gun chambered for .357?

    What about .44special out of a .44mag?
  17. Sunray

    Sunray Well-Known Member

    "...So what gives?..." Hi. Simple. Different bullet weights using different powders. Think velocity.
    "...So, one could shoot a hotrodded .38 out of any gun chambered for .357?..." Yep. The .357 mag is just a .38 with a longer case. However, you'd get gunk buld up in the chambers.
    "...What about .44special out of a .44mag?..." Ditto. Except that the .44 was made for lead bullets.
    It's better to use .357 or .44 mag cases in revolvers made for them, but using .38 Spec or .44 Spec. loads. The theory is that the bullet is closer to the barrel than a shorter case. There's less gunk build up. Done it.
  18. Jim K

    Jim K Well-Known Member

    Hi, Sunray and Jim W.,

    On shooting .38 Special out of a .357 and .44 Special out of a .44 Magnum, each has been done thousands and thousands of times. A good cleaning takes care of any "gunk" buildup. Accuracy does not seem to suffer in any appreciable way from the "jump".

    Jim, I admit to generalizing on the 1/10 inch. I should know better with folks waiting to zing me on a mistake.

    As to the reason for lengthening the .38 Special case, the initial load produced in early 1899 was only 18 grains of black powder, which will easily fit in a case the length of the .38 Colt case, so the extra length would not have been needed. The original .38 Colt military load was 18 grains (BP), but that was found to be too "hot" for the revolver and was reduced in Sept. 1892 to 15.4 grains (BP), giving a muzzle velocity of about 750 fps. So the .38 Special in early 1899 was more powerful than the .38 Colt service round was at that time, but not more powerful than it had been originally. Since military experience had shown that 18 grains (BP) was too hot for the Colt revolvers of that era, it would seem expedient for S&W to lengthen the new case to prevent its use in the Colts. I am quite sure the longer case was also part of the "hype war" between Colt and S&W, as was the name ".38 S&W Special".

    In mid-1899, the powder charge for the .38 Special was increased to 21.5 grains (BP) which fills the case with just enough room for the bullet. So from the overall history and chronology, it seems more likely that the case length was in fact increased to prevent .38 Special from being fired in the Colt revolvers, then the extra case length was taken advantage of to further increase the power. (The first .38 Special smokeless powder loads were produced in September 1899, so in any event the .38 Special did not remain a black powder cartridge for very long.)

    Not coincidentally, the first S&W .38 Special revolver, the .38 HE Military and Police, was marked ".38 S&W SPECIAL AND U.S. SERVICE CTGS", indicating that both rounds could be used, certainly an important selling point in S&W's effort to obtain adoption of its new revolver as well as encouraging private sales to military personnel.

  19. Jim Watson

    Jim Watson Well-Known Member

    That is all news to me. Where can I read more? 18 grains too much powder? I know they found 40 grains too much for a .45 and cut that to 35 and then 30 but have never heard before that the original .38 was considered overloaded.

    I do not see how lengthening the case would keep a .38 S&W Special from chambering in a .38 Long Colt that had the chambers bored straight through and will easily take a .357. When did Colt start making revolvers with throated chambers?
  20. Jim K

    Jim K Well-Known Member

    Hi, Jim W.,

    The information on the .38 Colt loads came from History of Modern U.S. Military Small Arms Ammunition, 1880-1939, byt Hackley, Woodin, and Scranton. Info on the .38 Special came from U.S. Cartridges and Their Handguns by Chuck Suydam, and from my own previous knowledge.

    Later Colts of that series were made with barrel shoulders, but I have not been able to determine when the change was made. Perhaps this was a reversal also, with the shoulders put in after the .38 Special came along to prevent the later cartridge from being used, but I think the change was made earlier, at least in the civilian guns.

    There does seem to be a lot yet to be learned about the revolvers of that era, both Colt and S&W. I understand some books are in preparation on the Colts, but have not seen anything yet except a couple of magazine articles and mentions in books on Colts in general.


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