Van, don't know about the rest of the guys you shoot with but if you were just shooting you could use anything. Cause it won't matter you won't hit it anyway....hehehe. Just kidding bud, 1/2" steel is the norm. And if you can weld a length of flat stock to it and a section of 1" black pipe, you can slide a piece of rebar or 1/2" conduit thru it and make a swinger out of it.
It will last longer from taking the smack from those big chunks of lead.