Re: How do you determine angle of deflection for bullets off concrete

The question: "How do you determine angle of deflection for bullets off concrete? I am police range master and want to teach officers about bullet deflection off ground and walls for their safety. I have read your section on windshields. I have experimented with our ammunition and have hit targets but want to know how to determine angle deflection on concrete. I am concerned about the path a bullet will travel down a wall or across the ground and strike my officers. What is the minimum and maximum degree of angle that a bullet can strike the wall and travel along the wall?"

There might be information available somewhere on the Internet that could directly answer your question, but I have not been able to find any. It looks like you will have to do more experimenting.

I am myself a shooter, and here is how I would go about measuring the bullet deflection off concrete:

At a suitable shooting range set up a target a distance h_I from the side of a concrete wall such that a shot fired through the target will contact the wall a distance d_I downrange from the target. The angle I can be calculated from the equation
tan(I) = h_I / d_I
After the bullet deflects off the wall it can be detected with a suitably large target a distance d_D downrange from the contact point, and the distance h_D can be measured. The angle D can be calculated from the equation
tan(D) = h_D / d_D
With a sufficiently large set of angles I and D the behavior of bullets off the concrete should be pretty well understood.

Here are some interesting web sites which, though not directly related to your question, offer some suggestive information:

from Journal of Forensic Sciences

at Wikipedia

at SpringerLink

John Link, MadSci Physicist