[Marcello]

"Look, you can have penetration even 2000mm at 10km, but if projectile dont hit anything critical, tank will survive."

Then, I am afraid, you have absolutely no idea of what you are speaking about.The projectile hitting something critical is just part of the equation (an important part but a part).Overpressure caused by something entering at massive speed into a sealed steel box is an other.Then there is heat and splinters to consider.