Say what you will about Destiny, I think it's one of the best-looking games in years, with some very cool weapons just lying around for people to cruelly and unfairly pick up. My personal favourite is the hand cannon, because I am a Titan, and that's just how I like to get shit done.
Normally, hand cannons exist only inside Destiny, unless you get people like Zander Brandt, who specialise in turning fake guns into real fake guns.
His replica hand cannons are great. Especially when you see that they're not just hulks of wood ro plastic; they contain a ton of moving parts, should you ever want to walk around a con spinning the barrel and looking like you're about to ask directions to a distant Cosmodrome in Russia.
You can read about how Zander built the guns, and see more pics, at his site.