A guy I know was firing a black powder revolver, .45, I believe, and shot an oak stump. they were all bouncing off, thrown to the side, until he got one right square on a center point and it bounced right back into his chest. Slow, light, lowest possible sectional density is the one best way to make a bullet bounce right back at you. All you have to do is shoot at a material that it can't possibly penetrate or crush, and it needs to have a little spring to it.
You'll shoot your eye out, kid.