So I saw this picture on Pinterest and I thought GENIUS!!!! I clicked said picture and of course I was sent to flicker. Yep just a picture but hey we are smart enough to figure this out. Right?
It looks like a old bookcase with the shelves removed. Peg board in the back painted black. Hang up the guns. I think the most expensive thing to buy will be the pegs and the peg board. You can get free bookcases off of craigslist all the time.
I think you could also put the peg board on the wall but you would need 1x2 spacers so you could actually use the pegs in the peg board ;)