In the past, when testing rounds on auto windshields I usually tried to test them while they were still mounted in a vehicle. If I had donated windshields that were not mounted, I set them at a 30 degree angle.
Compound angles are also fun, as in standing on the passenger side of the vehicle and shooting across into the driver's side.
Compound angles are also fun, as in standing on the passenger side of the vehicle and shooting across into the driver's side.