Last night I read John Lott's book More Guns, Less Crime. Lott exhaustively analyzes crime results for all 3,054 counties in the U.S. and the effect of gun ownership (and concealed-carry laws) on those rates. Without exception, crime rates go down when gun ownership goes up. The most significant impacts are found among urbanites in cities larger than 500,000 people, among women, and among minorities -- the groups that, paradoxically, tend to be most in favor of gun control.
Two details especially caught my eye. One is that U.S. gun control laws were originally Jim Crow laws: they were enacted to keep guns out of the hands of black people in the South (see, for example, Cottrol and Diamond, "The Second Amendment: Toward an Afro-Americanist Reconsideration", Georgetown Law Review 80, December 1991). The other is that, despite all the worries about accidental gun deaths among children, statistics show that many many more children die each year from automobile accidents, drowning, and such than from accidental gunshot wounds. In fact, about twice as many children die each year from drowning in bathtubs than die from gun accidents.