there is 2 pages that should be checked.
1.: www.acthungpanzer.com
they have some info from the war aswell, like this one:
Nashorn in Action !
It is reported that in early March of 1945, Lieutenant Beckmann from sPzJagAbt 88 destroyed Soviet IS-2 at the range of 4600 meters near Marzdorf.
imagine the shot..."I can zee zomething in the horizon.....FIRE !!!"
2.: the best known and most accurate tank sim to date STIL is the original "Panzer Elite" and i know for a fact, that the forums there have ALL info of most weapons tested at most ranges, from most countrys.
that means everything from weather, angle, type of ammo, velocity, and all other thing's you can think off as important.
Sadly, I havent been on the original forum's for some time, as i'm only 1 of 2 peeps whom bought the game in Norway, or atleast played online with it.