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Thread: SAAMI pressures for .38 Super

  1. #1
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    SAAMI pressures for .38 Super

    I have been looking at a number of powders and trying different loads for reloading the .38 Super round. In the Hodgdon reloading data, they indicate for Winchester 231 powder and a 115 gr LRN bullet, a powder charge of between 4.9 grains and 5.7 grains the last resulting in a pressure of 30.700 CUP. This also results in a velocity of 1,191 fps. The SAAMi spec pressure however, is 36,500 CUP which would in all likelihood result in a velocity much greater. Does anyone know why the powder companies set their maximum charge weights so far below the maximum SAAMi pressure without even getting to, in this case, 1300 fps?

    I realize part of the issue is simple precaution. And yes, I subscribe to all the start low and build up, precautions that will no doubt accompany responses to this post. But Buffaloe Bore has .38 Super rounds that achieve muzzle velocity of 1410 fps. While I don't necessarily want to go full out wild cat, this round typically did achieve 1300 fps with a 130 gr bullet back in 1929, Are we total wimps today?

    Wade

  2. #2
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    .38 Super labeling was changed to "+P" a while ago.
    The super has been held low to try and ensure tools with .380 ACP guns do not blow things up.

    Do some searches on .380 ACP and .38 Super and the issue will become very apparent.

  3. #3
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    Really? Because .38 Super (+p) is too long to fit in a .380, or am I missing something? And I thought the use of the "+P" designation was to keep people from putting .38 Super into an older .38 Auto gun, since these are the same size otherwise. But there are no .38 Auto weapons being manufacture today. .38 Super has made .38 Auto obsolete, so only while shooting antique weapons would this come up. Meanwhile, mine is brand new.

    Wade

  4. #4
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    Old time reloaders like Elmer Keith would refer to the "balance point" of a powder as the load at which pressure went nonlinear.
    I suspect that is what you are seeing with 231 in .38 Super. Likely when they exceeded 5.7 grains, the pressure started climbing fast without proportional gain in velocity.
    Hodgdon shows other powders at higher pressure and velocity. Although none as high as the SAAMI maximum.

  5. #5
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    Jim, Thanks, that does make sense. How do you find where these "balance points" are? While I don't want to get to maximum pressure, I would like to develop a higher speed round. Interestingly, Lil'gun apparently provides 1310 fps at 27,000 CUP, which didn't really make sense to me, but I am willing to look more into the chemistry of smokeless powder to find out.

    Wade

  6. #6
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    Quote Originally Posted by PolyKahr View Post
    Really? Because .38 Super (+p) is too long to fit in a .380, or am I missing something? And I thought the use of the "+P" designation was to keep people from putting .38 Super into an older .38 Auto gun, since these are the same size otherwise. But there are no .38 Auto weapons being manufacture today. .38 Super has made .38 Auto obsolete, so only while shooting antique weapons would this come up. Meanwhile, mine is brand new.
    I'm pretty certain brickeyee meant .38 Automatic, which is the cartridge the .38 Super was developed from. It's the same dimensions as .38 Super, so it would be possible to chamber .38 Super in older firearms designed for .38 Automatic pressures.
    Hawkmoon
    On a good day, can hit the broad side of a barn ... from the inside
    Last edited by Hawkmoon; 3rd June 2018 at 11:18.


  7. #7
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    Got it. Sorry Brickeyee, I humbly apologize.

    Wade

  8. #8
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    Jim, Thanks, that does make sense. How do you find where these "balance points" are?
    At my level of expertise, I am going to take the manuals' word for it. When they quit increasing loads even though they haven't reached the absolute maximum pressure, I quit increasing loads.

  9. #9
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    Quote Originally Posted by PolyKahr View Post
    Got it. Sorry Brickeyee, I humbly apologize.

    Wade
    Not required but noted.
    It gets real bad real fast with the less than accurate names used for these older pistols.

    And like everyone I do it occasionally.
    And thanks to Hawkmoon for understanding the mess.

  10. #10
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    Me thinks that some of the published results are not necessarily based of pressure but on the overall results. Sometimes more powder which means more velocity but not always better accuracy.
    Ken
    "I like Colts and will die that way"
    "It seems to me that I have forgotten more than I remember"

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