If I'm treading on politics unintentionally then I apologize in advance and I won't take offense if its deleted, as that wasn;t the intent.
The US is very diverse due to its size so statistics over the whole country are pretty much meaningless. We have states that are the size of whole countries with laws relating to guns/knives and/or self defense as varied as different countries. So you have to look at a smaller slice to get anythng meaningful.
Looking at murder statistcs the higher the rate is usually around larger cities such as NY, Chicago, etc and lower when you get into smaller towns and rural areas. So murder/crime is higher in part just due to more population density. Then there are the higher rates due to more strict self defense laws which do allow some more crime to happen because weather you agree with those laws or not, having guns or other means of self defense is a crime deterrant and having one more was to deter crime can help to reduce it.