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Reloading pressure ?

Discussion in 'Uncategorized Threads' started by timb99, Aug 31, 2008.

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  1. timb99

    timb99 Well-Known Member

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    This subject comes up from time to time.

    LUP stands for lead units of pressure and is a bit archaic. Instead of a piezoelectric pressure transmitter in a test gun, directly measuring pressure, they used to use a small lead pellet and measured how much the pellet deformed, and related that to a pressure number.

    A better discussion of this is in Lyman's reloading manual.

    The two, LUP and PSI are not directly related, that is, there is no "formula" to convert one to the other.
     
  2. halfmile

    halfmile Well-Known Member

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    There are SAAMI specs for max pressure in all firearms. NOne of the manuals will give data for overpressure loads.

    Although they do not convert mathematically, you can get a feel for it after a year or 2.

    I load for 1200FPS and mid range pressures. Low pressure loads tend to burn dirty, and as far as high pressures It doesn't hurt but patterns are a little better with pressures not on the hairy edge.

    HM
     
  3. timb99

    timb99 Well-Known Member

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    "Also why would they change the way they inform a person through out the manual?"

    Its possible the test was done with the crusher method in the past, and the results are still valid, so why go to the trouble and cost of re-doing the test just so the results can be expressed in psi?

    More recent test data are all in psi.
     
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