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Thread: Formulat for bullet weight / twist / charge?

  1. #1
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    Formulat for bullet weight / twist / charge?

    All this experimenting with loads makes me think that there must be a scientific way to relate bullet weight / twist rate / charge for optimal accuracy. Is there a way to calculate this besides endless trial and error?

    Steve

  2. #2
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    variables in the formula

    Steve,
    I have seen a few formulas posted on this forum dealing with the proper load and twist rate for a projectile. Unfortunately, there are lots of other variables and in the end; it goes back to trial and error.
    Besides weight of the projectile you have to consider the diameter of the projectile in the formula and the strength of the powder. Swiss powder is relatively stronger than GOEX and burns cleaner. The USIMLT posted an investigation that indicated it was about 20% stronger and I have found that to be correct. So how strong a powder are you going to use?

    The barrel length, diameter and the mounting of the barrel to the rest of the arm will also affect the accuracy results you get. I suspect that in the end, you ask your best friend how much powder he would use and then go from there. You might want to let him take the first shot!

    George
    Forrest Escort Company, Deep South Region

  3. #3
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    I've got links to some formulas posted here: http://acwsa.org/Pages/ShootingNotebook.htm
    Gary Van Kauwenbergh
    Co G, 114th ILL Vol Inf
    # 10143

    "Alle Kunst ist umsonst Wenn ein Engel in das Zündloch prunst."
    (In vain the skill and arts of man, When an angel pisses the priming pan.)
    Field Marshal Gebhard L. von Blücher

  4. #4
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    Nice web site, thanks!

    Steve

  5. #5
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    Look in some of the older Skirmish Lines for great information on this subject by Dave France.
    N-SSA Member since 1974

  6. #6
    David Disher 12143 is offline
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    You just have to start somewhere, and work it until it works. To quote a guy who has been around the N-SSA block a few times "....feed it what it likes."

    Ddisher

  7. #7
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    What got me going on this line of thought was a post over on the Firing Line that made reference to "Greenhill's Formula" for calculating twist rates and/or bullet lengths.

    Steve

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