I'd like to build my own and have some questions. I found a website that had some good pictures of how one is put together. He was using 1/4 steel for .22 shooting. Would their be any more chance of richochet if a person bumped that up to 3/8, and if I did make it out of 3/8 plate would it hold up to 9mm or 45acp. Is 8" circles the standard size. I'd be constructing it out of standard steel no special hardened stuff, just leftover plate.