@Shoota - No legislation, however perfect, will guarantee that such instances never happen again, and given the prevalence and attitude towards guns in the US, I find it difficult to believe they will ever change to a more gun free environment.
It is very difficult to imagine any justification for allowing automatic assault rifles or sub-machine guns or machine pistols to be legally owned by a private citizen though. With their high rate of fire and large magazine capacity, they can create a huge amount of carnage in a very short space of time, so imposing a ban might at least limit some of the damage in any future rampage.
It would be much more difficult to go on a spree-killing rampage resulting in large numbers of fatalities, if you had to reload after every shot, or if the only guns you had access to were target pistols, hunting rifles or single or double barrelled shotguns......
There was a recent rampage of sorts in China, where the assailant was armed with a knife - 22 injuries, 9 serious injuries, all kids, but no fatalities - compare and contrast with what happened here, or even what Breivik got up to in Norway?
How many kids could Hamilton have killed in Dunblane, if the only pistols he had access to were .22 target pistols, rather than 9mm Browning automatics, or .357 magnum revolvers?