I talked with Dick_cress and we thought this info may be of some use to a few of you out there.

mass 6. Abbr. m Physics. The measure of the quantity of matter that a body or an object contains. The mass of the body is not dependent on gravity and therefore is different from but proportional to its weight.
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Excerpted from American Heritage Dictionary
Copyright © 1997 The Learning Company, Inc.

The above definition captures the gist of the problem. The equation for kinetic energy is correct: K.E. = ½ mV2. What is missing is the conversion factor for changing " weight" to " mass" . To do that you must divide the weight of the projectile by " g" , the value of the acceleration of gravity : 32.16 feet per second (or 32.174 fps depending on your reference). Also, to arrive at an answer in foot pounds you need to convert " grains" to " pounds" . There are 7000 grains in a pound, so you also need to divide the weight (or mass) of the projectile by 7000.
K.E. = kinetic energy (in foot pounds)
g = acceleration of gravity = 32.16
w = weight of the projectile (in grains)
m = mass of the projectile
V = velocity of the projectile (in feet per second)

K.E. = ½ m V²

or

K.E. = wV²/ 2g x 7000

or

K.E. = wV²/450240


For some strange reason I can' t seem to get the underline or division line to work. The above formula is wV² divided by 2 g x 7000 or wV² divided by 450240. Hope this helps.