Frogwatch wrote:
In my thread about target shooting on the water, someone mentioned
bullets bouncing back and had a vid of this happening when a .5 cal
bounced from a steel plate.

First, some easy to remember physics: Light things do not transfer
energy to heavy things well, that is why the bullet bounced back from
the steel plate. Heavy things do transfer energy to light things well
which is why sand absorbs energy from a bullet so well.

Although a bullet will bounce at a shallow angle from water or sand, I
doubt it is possible for a 180 degree bounce to happen. OK, it is
"possible" but it is probably more likely you will get hit by a
meteorite twice.
A friend of mine learned about bullets bouncing back and geometry all in
about a second. There was a bridge that crossed the creek at a sharp
angle which created a pocket that was a triangle between the abutment
and the bridge. He decided that was a perfect place to put the cans he
was shooting at. He lined up the rifle and shot. The bullet left the
gun, hit one side of the triangle, then the other side, came right back
along the gun barrel, enter his skull just above the eye but below the
bone, and passed out through his temple. Fortunately he did not plan it
otherwise he would have been dead, since he could not have set up the
shot so perfectly.

I think it is physically impossible for a bullet to make a 180 when it
hits the surface of the water. To make a 180 it would have to hit
something like steel or concrete that would reflect the bullet back on
its original path.