Then there's the issue of violent crime, not just murder by firearms. Here's some interesting data from Australia.
"It is a common fantasy that gun bans make society safer. In 2002 -- five years after enacting its gun ban -- the Australian Bureau of Criminology acknowledged there is no correlation between gun control and the use of firearms in violent crime. In fact, the percent of murders committed with a firearm was the highest it had ever been in 2006 (16.3 percent), says the D.C. Examiner."