I was looking at upgrading my back stop for my back yard range. Currently I have my 5 archery foam cubes in a row that are behind my targets and then also 2 straw bales behind that. The targets are getting some age on them and ALOT of holes and I thought it was time to decluster the yard and upgrade it. I am wanting to get a 4'x8' sheet of 3/4" plywood and then attach rubber matting on either one side or both sides to become a backstop...my question is how thick should I go on the matting. I work for a factory that supplies equipment for coal mines. I will not have a problem getting some scrap pieces to make this work. We have up to 3 inch thick rubber belting at the plant right now. Any ideas would be greatly appreciated.