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Thread: Pressure Data in Manuals

  1. #1
    Boolit Buddy

    RedHawk357Mag's Avatar
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    Pressure Data in Manuals

    I was talking with a older reloader today and we were talking about a 10mm reloading project we plan on doing in the future. We got to comparing pressure values. Later I was looking at my data library and it came to my attention. Speer #14, Alliant 2014, doesn't include pressure values. While Hodgdon 2019, Western Powders, (year escapes me), Lyman#50 all include pressure data. I imagine this question has been asked before but does anyone know why the above mentioned sources quit including the information in their publications?
    Having never actually seen QuickLoad in operation, but from my layman understanding where does the software get the pressure values if powder companies aren't publishing the information? Thank you.

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  2. #2
    Boolit Grand Master Outpost75's Avatar
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    QL is an educated "guess". Values are not absolute, but a reasonable approximation of what you might expect, and is better than a wild guess. I would not take QL as gospel, but is is better than having no freaking idea and going entirely by guess and by golly!
    The ENEMY is listening.
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  3. #3
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    Lyman 4th cast bullet manual simply states "where no pressure readings are shown, we did not take pressure readings and focused on powder charge"

    IN other words, showing you the pressure reading for a particular loading, MAY cause you to wet your pants, Or they simply did not take it, or got to much variation between shots that it wasn't worth the time.

  4. #4
    Boolit Grand Master


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    Quote Originally Posted by Outpost75 View Post
    QL is an educated "guess". Values are not absolute, but a reasonable approximation of what you might expect, and is better than a wild guess. I would not take QL as gospel, but is is better than having no freaking idea and going entirely by guess and by golly!
    Outpost75 is correct, QL is only a guess that depends on how much data you input and how correct that data is. Much the same as the old Powley Computer. Most data in the latest manuals of those companies that actually test their own loads has been pressure tested and found to be with in SAAMI or "safe" limits with their own test fixtures/guns. Manuals that plagiarize data from other sources are, in my opinion, questionably reliable. The manuals admonition for you, the reloader, to start low and work up always applies. Far too many just assume the top end load will be safe in their firearm. That is not always the case......always start low and work up looking for pressure signs.
    Larry Gibson

    “Deficient observation is merely a form of ignorance and responsible for the many morbid notions and foolish ideas prevailing.”
    ― Nikola Tesla

  5. #5
    It’s generally not what the gun will take but what the brass will handle. More importantly what your brass will handle in your gun. Doing your own work up is best, working your way up watching for pressure, preferably over a chrono.

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check