[SampleMan]

You have to get a grip of the time frame.

Plasma has many different meanings in different sciences. For the sake of this discussion I'm talking about super heated gas which is under such enormous pressure it is actually solid again, but not in a "pick it up and look at it" sort of way.

An example of such plasma is a shaped charge. The Monroe effect describes this. When a shaped charge (RPG) detonates, the power of the explosion turns the concave copper into a slug of plasma. If atmospherically released it would turn to gas, but it is under tens of thousand of psi from the explosion, this explosion holds the plasma to the armor, which turns out to be the path of least resistance. In micro seconds (before the explosion shock wave can move 1 foot, the plasma turns the adjacent metal into plasma and burns a hole right through.

Some relatively small explosives (size of you fist) can thus penetrate 12 inches of steel. The hole is less than an inch in diameter, but when the plasma reaches the essentially unpressurized interior it turns back into gas (an explosion) and turns the inside of a tank to an instant 4-5000 degrees.

I take you back to the bird strike analogy. When you hit an object at 6000 miles an hour, it doesn't bounce off. It doesn't matter if its steel or feathers, all that matters is mass.