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Thread: Pressure Question?

  1. #1
    Member Smokey's Avatar
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    Default Pressure Question?

    Today I was looking at reloading data that Accurate Powders published and under the 35Whelen there were 3 - 225grain bullets by diff manufacturer's... OK, now they looked like this - numbers are roughly what I remember..

    Brand A 42gn of XYZ pdr = 2400fps / 41,000 psi

    Brand B 48gn of XYZ pdr = 2425fps / 49,000 psi

    Brand C 48.3gr of XYZ pdr= 2440fps / 49,900 psi


    Now what got my attention was the 8,000 psi it appeared they could have kept increasing pdr XYZ until it approached 49,000 range which should have gave Brand A bullet a major fps increase/advantage? So, is there a reason to stop at 41,000 psi that I am missing?

    Unless case capacity was maxing, and it should not have been, considering they used the same pdr and case in each load why would this be a place to stop on load A????

    Again numbers are only close memories of what I read but close enough to be fair...
    When asked what state I live in I say "The State of Confusion", better known as IL....

  2. #2
    Member dkwarthog's Avatar
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    6 grains of powder difference is pretty huge for a bullet of the same weight, Brand A.

    I am assuming that the 42 grain load was for a non lead bullet? In which case, maybe they were indeed running out of powder space at the same OAL???

    Edited to add:

    I couldnt help but go look at the accurate load site and something is odd about the 35 Whelen loads there. For A2015, 2230, 2460 and 2520, the barnes X 225 takes roughly a grain less than a 225 partition. But when you look at 2495, the 225 Barnes is listed at 2 grains higher?? Its taking more powder, being seated deeper and with less pressure???

  3. #3
    Member Smokey's Avatar
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    Ahhh DK, your onto something...
    I went back and my memory was fuzzier than I thought here are the numbers on one pdr ....
    NP 225 51.0 gn 52,200 psi 3.215 col
    Sierra 225 49.5 gn 51,300 3.28
    Barnes X 225 53.0 gn 48,800 3.22

    Better numbers to work with... So it does appear col was the factor. Now as a reloader lets take the Xbullet and assume the rifle could take a longer col and the case more pdr, then there would be no reason one could not go up from 53. grains until the 51 - 52,000 psi range was hit correct?
    When asked what state I live in I say "The State of Confusion", better known as IL....

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    Supporting Member iofthetaiga's Avatar
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    Quote Originally Posted by Smokey View Post
    Now what got my attention was the 8,000 psi it appeared they could have kept increasing pdr XYZ until it approached 49,000 range which should have gave Brand A bullet a major fps increase/advantage? So, is there a reason to stop at 41,000 psi that I am missing?

    Unless case capacity was maxing, and it should not have been, considering they used the same pdr and case in each load why would this be a place to stop on load A????

    Again numbers are only close memories of what I read but close enough to be fair...
    Perhaps there is some sort of error in their data... That aside, and addressing the hypothetical question; not all powders, probably most powders, are not predictably linear in their behavior as charge weight increases linearly. As charge weight increases, a point may be reached where a given powder may suddenly begin to exhibit erratic pressure anomalies, etc. Perhaps Accurate determined the charge weight given for this particular powder was the max safely usable, despite it's pressure being less than the others.

    Edit: Then there are also lot's of other potential variables, as you posted while I was typing.
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    Member Smokey's Avatar
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    Quote Originally Posted by iofthetaiga View Post
    Perhaps there is some sort of error in their data... That aside, and addressing the hypothetical question; not all powders, probably most powders, are not predictably linear in their behavior as charge weight increases linearly. As charge weight increases, a point may be reached where a given powder may suddenly begin to exhibit erratic pressure anomalies, etc. Perhaps Accurate determined the charge weight given for this particular powder was the max safely usable, despite it's pressure being less than the others.
    Yes sir that was my thoughts as I drove home, I also had not paid attention to the col as DK brought up and it appears they were using the industry std for col in the data I looked at... Sometimes its hard to see the snake that's about to bite ya!
    When asked what state I live in I say "The State of Confusion", better known as IL....

  6. #6

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    I could easily see it if that 225 with the light charge was a monolith and so long they had to ram the bullet way down to stay within max COL. There just might not have been enough capacity for your hypothetical XYZ powder, though 42-48 grains seems low for the Whelen case. You see this kind of thing all the time when you get into shorter cases like the 358 Winnie. A long bullet just won't allow any more of a slow powder, even if pressures are low.

    If that bullet wasn't a monolith, I'll go sit in my corner and shuddup.

  7. #7
    Supporting Member iofthetaiga's Avatar
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    Quote Originally Posted by Smokey View Post
    Yes sir that was my thoughts as I drove home, I also had not paid attention to the col as DK brought up and it appears they were using the industry std for col in the data I looked at... Sometimes its hard to see the snake that's about to bite ya!
    Loading would be much simpler and easier if all powders were linearly predictable. There would also be far less need for so many different powders.
    ...he who knows nothing is nearer to truth than he whose mind is filled with falsehoods & errors. ~Thomas Jefferson
    I would rather have a mind opened by wonder than one closed by belief. ~Gerry Spence
    The last thing Alaska needs is another bigot. ~member Catch It
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    Member Smokey's Avatar
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    Quote Originally Posted by BrownBear View Post
    I could easily see it if that 225 with the light charge was a monolith and so long they had to ram the bullet way down to stay within max COL. There just might not have been enough capacity for your hypothetical XYZ powder, though 42-48 grains seems low for the Whelen case. You see this kind of thing all the time when you get into shorter cases like the 358 Winnie. A long bullet just won't allow any more of a slow powder, even if pressures are low.

    If that bullet wasn't a monolith, I'll go sit in my corner and shuddup.
    Barnes X BB
    When asked what state I live in I say "The State of Confusion", better known as IL....

  9. #9

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    Quote Originally Posted by Smokey View Post
    Barnes X BB
    Ayup. Wudda benn mah gess.

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