Still don't get it, do you??
There is more explosive power, much more, in a gallon of gasoline than there is in more 308 ammo than you could carry. How you gonna keep Cho from buying gasoline?
Ordinary black powder is made from charcoal, sulfer, and bullshit (or any other sort of manure or biomass). How you gonna keep all of that out of Cho's hands?
Cars kill far more people than guns every year. How you gonna keep Cho away from cars?? I mean, a lunatic out for blood could just drive up onto the curb in many places and run up more of a score than Cho did.
Then again, Jack the Ripper never owned a gun. How you gonna keep knives out of cho's reach??
What about Axes (Lizzie Bordon never owned a gun either...)
What about the possibility of lunatics simply banding together and VOTING human sacrifices for themselves as the vermin which infest Durham NC recently tried to do when they returned the Fong to office as DA long after the realities of the Duke Lacrosse case were well known?? You gonna outlaw the de-mokkker-Rat party??
I mean, those losers are still protesting the fact that their vile little scheme was broken up:
http://www.freerepublic.com/focus/f-news/1821102/posts
Basic reality: If somebody is too dangerous to be walking around, then in theory at least, he needs to be LOCKED UP. Nothing else you could plausibly do is guaranteed to keep him from doing damage. And, if that idea is unacceptable to you, then you simple have to accept the costs of having these guys walking around and deal with it, as we accept the prices we pay for having motor vehicles.