Gun-control regulation will not stop violence. Part of the problem that Chicago and other regions with tight gun-control regulations have is that there is still a flow of guns into these areas from outside. It would be akin to me complaining that we shouldn't have pollution regulations because pollution does not stop at the borders. It is also the case that there is a correlation between poverty and violence. Those areas you point out as having 'failed' in their gun-control regulation also happen to have lots of poverty.
While I know it can be difficult for someone to change their pet ideology, I would expect that you as a 'trained' scientist would take the time to actually do some background research before drawing a conclusion.
Here is a study detailing the impact of the Australian 1996 law.Here is a 2011 Harvard summary of the research.