Around here last summer, a bunch of idiot kids were driving around and shooting the rear windows of parked cars with a pellet gun. Even that little gun had enough oomph to shatter the whole thing like nothing.
Later they (or someone else) would come through and steal everything they could get out of the car.
A windshield, however, has that nifty polymer stuff in the middle. It will spiderweb and get holes, but not fail completely. If you have the chance, go to a junk yard or wrecking yard and see if they will let you take a whack at a windshield before they recycle the car. Its a lot of fun, and rather educational.
also all the glass in modern vehicle windows is tempered, windshield, windows, rear window, moon roof, etc... windshield just has 2 layers with some polymer stuff in the middle