But I could swear that the damage model wasn't that good I know read it somewhere.
Better don't swear.

You may just remember vaguely what I also said above: Against objects, the damage is a constant, regardless on range.
But against all other targets (planes, boats, GV's), velocity is a big factor. 303's will lose a lot of power past 200yds. Or just test the Panzer 75mm vs the offline Tiger at various ranges. You will notice the difference. Or think why a Hurri D has to get really close to kill a tank....