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.