I have a really old (written in GWBasic) program that actually does all the caluclations. Got it out of an old Warship International It calculates the trajectory based on elevation, shell (a number of pramaters here like CHR, weight, etc.) air temperature, wind, gun elevation, and such. Penetration is calculated using the US Immunity Zone Slide Rule. This is theoretical rather than actual but usually comes out within an inch or so of actual penetration.
It might be available on line I'll have a look. I believe it was written by Nathan Orkim or some something similar to that.