During a shooting incident reconstruction class instructed by Forensic Science Consultants, we gathered some data on the critical angles of less lethal munitions versus automobile glass. These weapons are often used to break windows during critical incidents. What some operators do not know is that success in defeating the glass is heavily dependent on the attack angle. We found that automotive tempered glass resists 40mm less lethal projectiles at angles shallower than 70 degrees. 

Some of our critical angle data was presented at the AAFS meeting in Seattle, and the AFTE training conference in Nashville.