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Calculating Foot Pounds

Discussion in 'Handloading and Reloading' started by DMF38, Dec 10, 2006.

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  1. DMF38

    DMF38 Member

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    Does anyone know how to calculate foot pounds of energy? Suppose I'm shooting a 250 grain bullet from .45 Colt, and the measured velocity is 800 fps -- how would I determine the foot pounds of energy produced?
     
  2. The Bushmaster

    The Bushmaster Member

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    Bullet weight in grains X velocity squared divided by 450400 = ft lbs
     
  3. Sylvan-Forge

    Sylvan-Forge Member

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    From Lyman 48th edition

    bullet weight in grains x velocity squared
    divided by 450400 = ft-lbs

    edit: lol, The Bushmaster beat me to it
     
  4. DMF38

    DMF38 Member

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    Thanks for the help! :)
     
  5. Clark

    Clark Member

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    As every school boy knows, energy is equal to one half mass times velocity squared.

    The trouble is, guns are in the wrong units.




    Energy = .5mVV= one half mass velocity squared
    E = .5 [250 grains] [800 fps] 800 fps]
    E= .5 [250/7000 pounds] [800 fps] 800 fps]
    E = .5 [.0357 pounds] [800 fps] 800 fps]
    Mass = [wieght]/gravity= .0357 /32.2 feet per second squared = .001109 slugs of mass
    Es=.5[.001109 slugs][800 fps] 800 fps]= 355 foot pounds of energy


    Or you can just multiply grains times velocity times velocity divided by 45 and move the decimal place to what seems right.

    3555555.556

    Is a pistol 35, 355, or 3555 foot pounds?
    It must be 355 foot pounds.

    It does not matter, as Nicole Simpson took 5 foot pounds to the throat and dropped.
     
  6. Jay29

    Jay29 Member

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