So much is dependent on the range (kenetic energy), the angle of impact, and the composition of the projectile.
I hear players screaming that their X tank was taken out by Y tank. I always pipe up and ask the range and in most cases we're talking about that "sweet spot" range when the angle of impact is prime and the kinetic energy is still enough to defeat the armor in question. Case in point: try a Panzer IV H fire at a Panther at 400-600 yards away, squared up, and see if a frontal hit will destroy it. In my testing most of the rounds ricochet up and away thanks to the slope of the armor. Back off to 800 to 1200 and we're talking different results, the Panther will be sent back to the hanger. It isnt until about 1600 yards that the Panther becomes resistant to frontal hits by the Panzer IV H on down (Pzr IV H is at the top of the "mid" list, followed by the M4/76, M18, T34/85, Pzr IV F/2, M4/75, T34/76, etc). At 1600+ yards, the Panther only needs to fear the Tiger, Panther, Firefly, and King Tiger. Don't get me wrong, if the angles are right then the 1600-2000 yards kill shot can still be had, but then we're adding in some funky angles, etc.