Note that ft lbs is not fps. Ft lbs is a function of mass and velocity which is called kinetic energy. A 1/2oz 12 ga slug is .03125 lbs and assume its velocity is 1200 fps.

1/2 x (.03125 / 32.2) x (1200 fps x 1200 fps) = 698.75 ft lbs.

Whoops that is a light slug. Lets change that to a 1.5 oz slug = .09375 lbs

1/2 x (.09375 / 32.2) x (1200 fps x 1200 fps) = 2096 ft lbs

So there you go.

Last edited by Tamid; 04/19/17 10:09 PM.
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