First up, let's see what happens with good ol' 9mm ball.

Here we see a gentleman putting a 9mm ball round through the windshield of the Buick.

Here is the resulting target.

The red dot in the center was the point of aim used when firing the weapon.

The hole marked up top is where the 9mm round actually entered the target.

Now .40 S&W.

Notice first of all how windshield glass has reacted to two gunshots at point blank range.

Windshield glass is a laminate designed not to shatter upon impact.

This laminated glass is much tougher than any other glass on the car and can have dramatic effects which we will discuss later.

And the resulting target.

Note the bullet holes made in the glass as seen from the outside.