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Thread: Powley psi Calculator

  1. #1
    Boolit Master
    Join Date
    Feb 2006
    Kaneohe, HI

    Powley psi Calculator

    Found this.
    Powley psi Calculator
    Hutton Rifle Ranch
    Greenleaf Canyon,
    Topanga Calafonia
    Also have the letter shipped with it.
    Kind of a slide rule powder calculator
    It says something about a "Powley Hand Loading Computer"
    Don't think I have it, but it may turn up.
    I've heard of this thing, but never tried it.
    Click image for larger version. 

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    Last edited by abunaitoo; 01-21-2020 at 06:32 PM.

  2. #2
    Master Tool & Die Maker

    Red River Rick's Avatar
    Join Date
    Jun 2006
    Winnipeg, Manitoba, Canada.
    They work great for working up a load.

    Click image for larger version. 

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    "I Make the part.............................that makes the parts"

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  3. #3
    Boolit Grand Master

    Larry Gibson's Avatar
    Join Date
    Jul 2005
    Lake Havasu City, Arizona
    Back in the late '60s when I began studying ballistics (all 3 phases) I got the Dupont charts, the Powley computer and Speer's ballistic computer. All were useful at the time but I quickly learned that the more accurate I was in input the more accurate was the output from all of them. It's the same with QuickLoad and other ballistic calculators today. Input of correct and complete information is necessary for accurate output of data. I was even more impressed with that fact that they were just "estimations" when I got my first Oehler chronograph in '74. I found that velocity estimations with any such "calculators" were just that; an estimation. When I got the Oehler M43 PBL 12 years ago and actually started measuring pressures and ballistic coefficients that fact was even more apparent.....garbage in always equaled garbage out. However, once I got used to using the charts and computers (slide rules) I found, after actually measuring velocities, pressures and coefficients, that the results could be closer than attempting to use interpolated velocity and/or pressure from data in reloading manuals. One important thing I learned as to velocities and BCs; we want to be optimistic and round up.....don't. Rounding down will give better results of more realistic numbers. With pressure calculation it's best to round up and assume the pressure is higher...…

    Also, they are just a tool. It's best not to use them to determine a load, especially a max load, and then go load it. Always work up and use them as a guide, as a tool in that process.

    Click image for larger version. 

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    Last edited by Larry Gibson; 01-22-2020 at 09:51 AM.
    Larry Gibson

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

  4. #4
    Boolit Grand Master Outpost75's Avatar
    Join Date
    May 2013
    over the hill, out in the woods and far away
    ^^^^What Larry said^^^^

    What most amused me when visiting BRL on a project back in the 1970s, we were discussing how to measure nutation and precession on a projectile, calculating yaw drag and gyroscopic stability factor, Dr. Robt. L. McCoy explained how they just installed instrumentation in a 40mm homologue projectile, fired it and measured it. By the 1980s they could miniaturize it to fit it down to a cal. .50, now who knows...

    The Oehler machinegun chronograph of that era was facinating... As was firing backwards into the transonic aerodynamic range at night and taking spark shadowgraphs of 168-grain M852 as transonic buffeting occurred as velocity decayed beloqw the speed of sound at about 700 meters, which resulted in development of the 175 MK used in the M118LR sniper ammo.
    The ENEMY is listening.
    HE wants to know what YOU know.
    Keep it to yourself.

  5. #5
    Boolit Master RU shooter's Avatar
    Join Date
    Nov 2006
    SW Pa.
    My Dad still has his he bought in the early 60's
    If you find yourself in a fair fight, your tactics suck!

  6. #6
    Boolit Master
    Mr Peabody's Avatar
    Join Date
    Dec 2005
    I bought one in the 90's. I used it to work up loads for the .33 Winchester. Information for that round was scarce, this helped me get going. Hutton Rifle Ranch was in Boise Idaho by then.

  7. #7
    Boolit Master

    Join Date
    Oct 2009
    Northern Michigan
    I have one as well.

    Showing my age I guess.
    Don Verna

    NRA Endowment Member

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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