I'm wanting to build a bullet catcher that can be moved with relative ease (I can't really have a permanent catch on my range). Here's what I was thinking. I can build a box out of 2x4s and plywood. It'll be 24" tall, 18" wide, 24" deep, and filled with rubber mulch. I can build a stand for it to sit on, and the whole thing can be moved into the barn when I'm done shooting. The most powerful thing I plan on shooting it with right now is a 44 mag out of a 20" rifle. Should 24" of rubber much be enough to stop 44 magnum (I shoot a pretty good amount of it as my username would imply)?