After I lost money to a friend the first time, this was my outlook as well. It only cost me a thousand bucks to never see the prick again. I've been down that road with family too and now I don't loan money to anyone.
He can be a great guy and a good friend but just may have no sense of responsibility or just be a deadbeat when it comes to paying bills and you have to find that out the hard way.
You have one option, though, that you can try as a last ditch effort. It's a dick move, but since you are writing off the friendship anyway and he's not really a friend any longer you might consider posting to his facebook wall something that DOES cause him to lose face with people - nothing derogatory, but maybe along the lines of "glad to see you are back on your feet again, perhaps you can finally pay me for the rifle I bought you or just give it back to me". When all diplomacy fails you can resort to this kind of tactic.
I think you're pretty much out the money bud!