The RAAC Memorial and Army Tank Museum at Pukapunyal in Victoria has a display showing the effects of various rounds on armour plate which had been cut from a naval ship in the process of decommissioning. Everything from a 2 pounder up through an early guided missile and 105mm AP.
I think there's about a dozen plates one behind the other with about an inch or so between them. Some rounds only penetrate one or two plates, while the larger ones bore through several feet of hardened armour before stopping.
It's a shame they don't have those plates (which are located just outside the front door) on their website.
http://www.armytankmuseum.com.au/i-vd.htm
On the other hand, one of the friendly staff might take a few photos of them if you were to ask nicely.