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LUP vs PSI

Discussion in 'Shooting Related Threads' started by RHAT, Mar 1, 2010.

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  1. RHAT

    RHAT Member

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    Is there a method of determining how much presure (in PSI) a load that is listed as 11,000 LUP,..... ??? is it the same,??? or +/- a %

    I'm thinking there is a factor to multipy by,..... any ideas,???
     
  2. skeet_man

    skeet_man Well-Known Member

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    No conversion between the two...
     
  3. jimrich60

    jimrich60 Member

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    The two figures are obtained by totally different methods of pressure measurement and there is no way to simply convert one measurement into units of another. They most definitely are not equivalent.

    Jim R
     
  4. RHAT

    RHAT Member

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    Why are some loads listed in LUP,. and some listed in PSI??????
     
  5. wayneo

    wayneo Active Member

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    Gunnersden has lots of info. Wayne
     
  6. jimrich60

    jimrich60 Member

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    Depends on when and who developed the original load data. Lead Units of Pressure (LUP) is an older method, using the compressibility of lead to determine pressure. PSI is measured by use of Piezoelectric sensors, which are more accurate and provide a better measurement of relative pressures than trying to measure the relative compression of lead. However, since many of the "older" loads are still valid and work well, many powder and ammo makers continue to use/list these loads with their original developed pressure data.
    As long as you stick to loading data listed as within safe and prudent operating pressures in your shotgun, and don't exceed "maximum" data, it really does not matter which units of pressure are listed.

    Jim r
     
  7. Grizzlyman

    Grizzlyman Member

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    As stated by the other posters, there is no formula or conversion for LUP to PSI. Most of the older LUP listed loads can be found in PSI somewhere. There may be some that you simply cannot find tested by piezo in PSI ratings, however. The published loads are generally safe to use, but know that you really have no idea what the peak pressures are. Try to use a listed PSI tested load.
     
  8. Jack Frost

    Jack Frost TS Member

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    PSI is always 500 higher than LUP . example 11,000LUP = 11,500 PSI

    10,500 PSI = 10,000 LUP

    J.F.
     
  9. Remstar311

    Remstar311 Member

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    Jack can you site that information?
     
  10. Jack Frost

    Jack Frost TS Member

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    Yeah, 4th edition reloading for shotgunners by Kurt D. Fackler and M.L. McPherson. In the beginning chapters of the book.

    J.F.
     
  11. Easystreet

    Easystreet Well-Known Member

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    I think that Jack Frost got that information from some place that is dark and stinky.

    Easystreet
     
  12. timb99

    timb99 Well-Known Member

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    Lyman and Hodgdon say differently. Both say there's no correlation.

    Lots of Hodgdon's data for Clays powder is in LUP. If its a listed load, its safe to use.
     
  13. Jack Frost

    Jack Frost TS Member

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    Easystreet that is very childish thing to say. If you knew me at all, which you do not, you would know that I am not one to talk out of my behind. If you have nothing to contribute I recomend that you forgo the verbal defecation and spare yourself the embarassment.

    J.F.
     
  14. Remstar311

    Remstar311 Member

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    Thanks for the site Jack I'll dig it up.

    Nick
     
  15. phirel

    phirel TS Member

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    Jack- I do hope that the formula in the book is the only error in the publication.

    Pat Ireland
     
  16. wm rike

    wm rike Member

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    PSI is a unit of measure. LUP is a method of determining a value for PSI. There is also CUP (copper), but both LUP and CUP methods are pretty outdated at this point. Piezoelectric methods are more state of the art.

    A crude analogy to all would be temperature, where degrees are the unit of measure. Temperature can be crudely measured with a wet finger held to the air or your significant other's complaints, but neither method is espeically accurate. Think of that as the LUP/CUP method. More accurate values would be obtained from a mercury, alcohol, or bi-metal thermometer, or from a thermocouple.

    As a practical matter, reloading recipes that reference LUP or CUP are probably pretty outdated. A lot of powder manufacturers are going back and rewriting (more conservatively, I might add) their reloading manuals based on newer, better data.
     
  17. Jack Frost

    Jack Frost TS Member

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    Pat, I cannot speak for the author(s) only for what is published in the book I referenced.

    Do whatever you like with it. On the other hand I see nothing from you that would prove it to be an error. Please educate us.

    J.F.
     
  18. waverider

    waverider Well-Known Member

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    I have seen comparative data, may have been in Lyman's 4th edition, where it varied by the amount of pressure. If memory serves me right, lower pressure there was a 1200 psi difference and upper end 500 psi. I think Jack Frost may just referring to the maximum pressure table that Fackler and McPherson have in their Reloading for Shotgunners.

    Jason
     
  19. Easystreet

    Easystreet Well-Known Member

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    Jack Frost,

    I apologize for my crude remark above, but I'm still not buying the idea that there is any direct correlation or formula to convert LUP to PSI.

    I can quote reliable sources also that agree with what I'm saying. For example, I have a 14th edition reloading catalog from Winchester. Here is a direct quote from that manual.

    QUOTE: "All pressure data listed as psi has been measured with the latest Piezo electric system showing actual pounds per square inch (psi) and CANNOT be compared directly to the old data which used the lead crusher method (LUP)."

    I have read similar statements in quite a few other writings, but this one spells it out clearly and the Winchester reloading manual is certainly a reliable source, IMO.

    Easystreet
     
  20. Neil Winston

    Neil Winston Well-Known Member

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    Say we just agreed they are about the same. What would we do differently (assuming we followed the book)? Since all we really need to know about pressure is that 6000 is not enough and 10,000 is better and about right and that's about all - that sort of range - you are going to find in the book anyway.

    Neil
     
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