I think we can all agree the goal shouldn't be to stop murders from gun-related violence. The goal is to stop murders. Looking at death from gun-related violence is completely irrelevant. If states with stricter gun control laws have fewer murders per capita than others, then you have a point. Otherwise, killers and still killing and just using different tools for the job.
has a murder rate of 6.7, and has arguably the strongest gun control laws in the country before NYs new bill.
has some of the weakest and has a rate of 12.3.
Gun availability makes it easier for people to act on rash impulses and kill with much greater ease. I can be mad and hit you with a baseball bat, but you're still far more likely to survive than if I shot you.