06 February 2005, 05:19
ALFWill's penetration index ?
W
06 February 2005, 12:50
WillAlf,
It's not my PI but from Art Alpin's
Any Shot You Want.
It is reportedly non-linear as 100 does not mean twice the penetration of a PI of 50. For solids it indicates the potential penetration, which generally I have found to be true, but every shot and every animal is different.
PI=(KE)(SD)/(100 A)
KE=bullet kinetic energy, ft-lb
SD=sectional density, lb/in^2
A=bullet x-sectional area, in^2
Ex., 400 gr. 416 at 2400 fps gives PI=124.2