I have had a lot of experience and training in shooting into windshield but one day back in 08 I got to wondering what would happen if I was in my truck and needed to shoot out.
My son who was in autobody, at the time, scored a cracked but very useable and still strong windshield from the same type of chevy truck I drove. We measured the distance from the passenger and driver pointing a weapon straight head out the windshield and marked the spot on both sides on his windshield with sharpie markers and used that as our aiming point thru the glass. We built a wood bracket to hold it at the correct angle and set in on a table. We held the muzzles the same distance as we would be shooting from full extension over the dash/steering heel. We made sure we had full wrap around eye protection! He fired a G19 9mm 147gr flatnosed reload and I fired a G17 9mm 115gr+p JHP Remington. We both aimed center mass of the target at 7ft the approximate distance a target might be in front of the truck posing a threat. The results were that both bullets deflected upwards and hit the target in the head to the side depending on the curvature of the windshield. As a sidenote we noticed that the flatnose put alot of glass framents into the target and the HP soaked them into the cavity. Lessons learned (1) aim low shooting out (2) wear glasses (3) very little glass backsplattered into us at all (4) the cost for this test was very little with resourcefulness (5) This was FUN!