If someone opposes a gun-shop owner knowing that he's schizo, then chances are he's trying to buy a gun to shoot whatever he see's (being a schizo). Fuck the mentally ill's egos, I don't want to die. I do want to go hunting. I don't want people using fully-automatic guns for "home-defense". I do want to be able to defend my home, I just don't want the bullets to go through a wall, kill my one of my brothers, mother, or father (see: pretty much any rifle caliber, or fully-auto guns). I do want to shoot ducks in-season, but I don't need a full-auto shotgun to do it. I do want to shoot a pistol in competiton, but I don't want to use a fucking armor-piercing bullet, or anything greater than .45 caliber in terms of muzzle velocity (the average .45 ACP only travels 1200 fps, which can easily be stopped by your average house-wall at ranges of 10 feet or more).
Look at Finland. 50% of houses own a gun (source: Download the PDF in that link, the one titled "United Nations International Survey on Firearm Regulation" . Its even legal to own an AK-47 in finland (just not in full-auto). Just look at where they compare to the US, even though its legal to own most kinds of firearms! If you don't believe me that they can own AK-47's, just look at this guy.
If you live in the US, please, for the love of god, contact a senator or something! I've e-mailed Claire McCaskill (US Senator, Missouri), and I've spammed the hell out of every local legislator I could find. Maybe if enough people start bitching, someone will say: "So apparently US Citizens are concerned about the mentally insane owning guns...". Its worth a shot.