Bullet hits

Things that run through my mind when I" am trying to get to sleep.

How does hollywood do those bullet hit on a car and how do they do the hits on glass such as car windows.

Seriously. I have searched over a dozen times and while I can find how they do squibs such as on an actor, but I haven't founf exactly how they have done the breaking glass nor the hits on metal such as you see in this scene from Heat.

I DO know that in this particular clip from the Movie Heat, they used the actual sounds from the scene as it was shot. Those aren't dubbed gunshots, those are the real shots as recorded when they shot the scene. Listen to them echo in the scene.

Also see how the bullet holes appear in the car windshield, as they are shooting. How do they do that?

I have yet to find the answer on my dozens of Google and Youtube Searches.