doesn't look like .50 cal will penetrate tank tracks from an airplane at any range...and .30 cal will just scratch the rust. and depending on the construction, even the road wheels could be safe.
A couple of things to consider.... WWII vintage tank tracks were not as strong as spec armor plate. They were usually inferior to common 1010 cold rolled steel. A .50 cal AP round will easily penetrate 0.5" of cold rolled steel. A second thing to consider is that deck armor of many tanks was 25mm or less in thickness. This means engines and fuel tanks may be at risk. Especially considering the erosive effect of many hits in a relatively small area. A heavy concentration of .50 hits can also shoot off radio antennas, damage optics, lights and anything else not armored.
An example of not penetrating armor, yet disabling a target can be found in the naval battle off of Samar in the P.I., October 1944. The USS Johnston scored between sixty and eighty 5"/38 hits on a Japanese Heavy Cruiser. Not a single round penetrated the Cruiser's armor. Yet, her superstructure was wrecked, the bridge demolished, central fire control knocked out and fires raged in several locations. She was effectively out of the battle, yet her vital engineering spaces, magazines and main guns were undamaged. Indeed, in the same fight, the Jeep carrier White Plains disabled another Cruiser with a single 5" hit. That round magically found the torpedo tubes amidships and caused two of them to detonate.
I suppose that my point is that one can never rule out anything....
