There were 30,470 deaths by firearm in USA in 2010
- 19,392 suicides and
- 11,078 homicides, including:
- 1,923 instances of killing during the commission of a felony, of which a mere 236 were the killing of a felon, during the commission of a felony, by a private citizen
You are 14 times more likely to use your gun to kill someone you know during an argument than you are to use it to defend your home.
A child in your house is more likely to use that gun to kill himself or another
child than you are to use it defensively.
And you are about a hundred times more likely to use it to kill yourself
during a bad moment than you are to use it against an intruder.
Over the last week I've been checking the claims that gun proliferation reduces violent crime and find them to be unfounded; The reductions in violent crime following introduction of "right-to-carry" and other state laws to encourage gun presence are no greater (actually marginally less) than year-by-year reductions in crime that had already been occurring everywhere in the US since 1990. More guns are not correlated with less crime.
Civilization "would be a good idea" but cannot stop massacres. That can only come from limiting civilian access to weapons of extraordinary destructive power.