None that we know of. That backstop works great, the range is divided into 4 parts, pistol range at the front, 50m and 100m rifle range in middle and down one side, and the rear part is used for clays. No fall out area or anything
There is a rather large glacis at the base of the rock. To get a ricochet you'd need to be aiming way up than a normal target, and even if you did, it most likely would strike another rock face and stop.
2x4's 8x8 1/8" steel plates on the sides. 1/2" plate in the middle for larger calibers.
They hang on s hooks and door hinges. When you hang them on a door hinge they hang at a slight angle back to deflect lead to the ground. No ricochets with this setup.