It's called a right to bear arms. It's a right because it was considered necessary for the defense of our basic rights.
In addition, most gun related homicides stem from drug or gang violence - and a large percentage of those cases are using illegally obtained firearms.
Some of those "homicides" (depending on the statistic set you're using) may be self defense cases.
So, I'm going to argue that we shouldn't be banning magnets just because some kid is stupid enough to swallow one. I'm also going to argue that banning guns, opposed to banning Bucky balls, does more harm then good, if only because gun ownership does not correlate with homicide..
(Some recent numbers for you)