It's the same issue again no matter how you slice it- city vs state. 
For example, in 
table 4 of the 2016 FBI statistics that I linked to earlier, you can see that violent crime in urban areas of the Northeast, where gun laws tend to be more restrictive, has been steadily 
decreasing.  These Northeastern cities have much lower crime rates than cities in the South.  You're more likely to be the victim of a violent crime in Houston where gun laws are lax (578.2 crimes per 100,000 residents) than you are in New York where gun laws are restrictive (354.9 crimes per 100,000 residences).   Even in high crime cities, it's the same trend- New Haven has a violent crime rate of 322.8 per 100,000 people but New Orleans has a rate of 558.8 per 100,000.
		
		
	
	
Source
One has to be very careful taking two statistics and inferring a correlation between the two.  One very reputable researcher has correlated gun violence and violent crime to abortion rates- 
eighteen years after the Rowe decision, violent crimes decreased and they have continued to decrease since Rowe; areas with easier access to abortion have declining violent crime rates while areas that are restricting access to abortion have not seen the same rates of decline.
Now, before we get off on a discussion about abortion, that's not the point.  The point is that Congress defunded research into gun violence- specifically 
gun violence- so we have incomplete data to make policy on (which was the goal of Congress' action).  The focus on mass shooting events by both sides of the gun issue isn't helping- both sides need to agree to look the research and come up with ways to address the problem.
I mentioned earlier that there are an increasing number of members of Congress who have personal experience with gun violence.  Senator Feinstein is one of those members.  She was at the San Francisco City Hall when Mayor Moscone and Harvey Milk were shot and killed.  She tends to be very rational on legislation and she does realize that allowing Tom Delay to block the renewal of the assault weapons law in the early 2000s was the turning point on a particular type of mass shooting.  However, I think she also knows that handguns and suicides are really the issue that needs the most attention.  
Actually, that's not what the research shows.  And to be clear- when I say "good guy", I'm talking about people who are specifically trained for these situations- law enforcement and military veterans, specifically.
There's two scenarios that we're talking about- one is a robbery/assault scenario and the other is an active shooter event.  The probably of most people encountering either is statistically low.
In the scenario where someone encounters someone with a gun in an assault, having a gun doesn't change the outcome.  Introducing a second gun into an assault scenario is likely to escalate the situation resulting in one or both parties will be shot.
In active shooter situations, experts do not encourage civilians to waste time with weapons unless they have been specifically trained for these scenarios.  In research where people were confronted with a scenario where a shooter attacked a group of people who had weapons and training, the gun owners were unable to process the scenario in a timely manner and they consistently, instinctively froze then ran.  
The only group who were able to respond in time were law enforcement people who were specifically trained on this scenario.  And the consistent complaint from this law enforcement group was that when civilians possessed weapons in the scenario, law enforcement was unable to distinguish the "good shooter" from the "bad shooter" and they would not hesitate to shoot everyone without a police uniform.
The recommendation from the experts is designed to both take advantage of human instinct and is based upon research on survivors of mass shooting events: ADD- Avoid, Deny, Defend.  Your best chance to survive an interaction with an armed person is to avoid confrontation and to get away.