I checked some numbers for 2002 I think it was. The state of Vermont and Washington DC both have around 600,000 or so people. In one year, Vermont had 6 murders, DC 262. DC had a total handgun ban, while Vermont at that time was the only state allowing concealed carry of a handgun without even getting a permit first (background check and training).
More on how the violence problem came to be:
In California, to this day gun carry permits are handed out at the personal discretion of police chiefs and sheriffs under a 1924 law specifically aimed at minorities. Heavy gun control was the norm in all of the areas with urban black populations, across the deep south, Chicago, DC, NYC, SF, LA, Detroit, etc.Gun control helped twist those "hoods".
Anybody honest had to commute outside the "hood" to work. Once in white areas they were subject to random search and couldn't pack. So once they got back home they were easy meat for the crooks hanging out in the ghettos - and as long as those crooks only preyed on other blacks and stayed in the areas cops never went into, they were perfectly safe packing heat.