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Copper Units of Pressure in Lyman

Discussion in '10mm Reloading Forum' started by pkersey, Apr 11, 2012.

  1. pkersey

    pkersey

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    Looking through the load data for the 175 grain lead bullet in the Lyman manual the max loadings list pressures ranging from 28,100 cup to 29,000 cup. I would like to know what percentage of the maximum these loadings give. Does anyone know what the maximum pressure rating for the 10mm is in cup? If cup and psi are roughly equivalent in this range it seems strange that the max loads listed generate more than 6000 psi less than the maximum pressure.
     
  2. _The_Shadow

    _The_Shadow Ret. Fireman

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    If you read data on the two measurements they do not directly correlate to each other...30,000 CUP doesn't equal 30,000PSI. There have been people who have tried to put together charts but were unsucessful.

    Also be aware that the strain gauge methods differ, those used by SAAMI are usually internal to the chamber others are being calibrated on the outside of the barrels.
     

  3. Yondering

    Yondering

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    Because the CUP and PSI measurement methods are so different, there is no direct conversion between them.
     
    Last edited: Apr 12, 2012
  4. gofastman

    gofastman

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    http://www.lasc.us/Fryxell_Book_textonly2.pdf
    see page 72
    (its a good read, go through the whole book!)

    Excerpt:
     
    Last edited: Apr 13, 2012
  5. pkersey

    pkersey

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    Thanks for the link gofastman, this is just the info i've been searching for.