Weapons expert.
I don’t pretend to be one, but you can,(pretend to be one, that is) if you memorize everything on this page and all the pages it links to. My favorite? Radioactive zombie badger launchers.
And now for something completely different: Fatboy Slim’s Weapon of Choice.

Yeah, but clearing a misfire? Oof; not fun. And don’t get me started on short rounds!