What you have to think about is what hit the tank and where. Armour piercing shot will often punch a fairly small, about fist size, hole on the exterior but create carnage on the inside as Molton shrapnel bursts into the crew or engine compartment usually causing fire which is the real tank killer. Ron depicted this very well on the model he mentioned.
HE, high explosive, shells do not pierce thick armour but a big shell or a small well aimed one can destroy a tank if it hits the right spot especially engine covers, external fuel tanks and tracks. Although knocking the tracks off disable a tank, it does not stop it fighting but it would be very brave or very stupid crew that sat in a sitting duck in a tank battle
Scan the net for pictures, there are tons of them. If you compare WWII with modern conflicts you will see some similarity of damage from normal anti tank guns but modern missiles really rip tanks apart.
As for how to get the whole in a model, a hot screwdrivers works well but practice on a crap bit of plastic first, if I remember right, that is how Ron shot his elefant (spelling?)
