"Penetration Index" = PI = (KE/CSA) x (Sectional Density)
"Shock Power Index" = SPI = KE x CSA
where KE = Kinetic Energy of bullet CSA = Cross-sectional Area of bullet M = Mass of bullet V = Velocity of bullet D = Diameter of bullet N and Z = numerical constant factors for converting between Sectional Density (square bullet convention proportional to reality) and CSA (round bullet reality) for a particular "Index" formula N is used for PI formula Z is used for SPI formula
So by the same reduction to factors as I have been foisting on Sir Bob:
PI = N(M^2 x V^2)/ (D^4) = Momentum squared divided by bullet diameter to 4th power and all that multiplied by a constant numerical factor.
SPI = Z(MV^2)/(D^2) = Kinetic Energy divided by bullet diameter squared and all that multiplied by a constant
Such is the genius of Art Alphin, who claimed he got a Bachelor of Science degree in "weapon systems engineering" from West Point. During the brief time I attended West Point (until they quit Vietnam and I quit them), there was no such degree. There were no majors then, just an all-purpose BS from West Point. Art designed the SAAMI .458 Lott throat with his advanced BS.
Allow me to suggest a new Lethality Index = SquareRoot[PI x SPI] = BS2 Index
BS2 Index = Square Root of [N x Z x M^3 x V^4 / D^2]
BS2 Index = (New Constant) x (Square Root of bullet Mass) x (Kinetic Energy at Impact) / (bullet Diameter)
Ron aka "Rip" for Riflecrank Internationale Permanente NRA Life Benefactor and Beneficiary .458 Winchester Magnum, Magnanimous in Victory THE WALKING DEAD does so remind me of Democrap voters. Donkeypox.
