The murder rate has a lot to do with our constant gang wars. So, how do you get the guns away from the gangsters? Pass a law?Actually, the "Wild Wild West" was not that wild. The homicides attributed to those days were hyperinflated to sell dime store novels.
http://www.independent.org/publications/tir/article.asp?a=803
You really need to ask yourself why the US has more murders per capita then any other developed nation in the world, yet there is more then one gun per person here.
The murder rate increased by 20% in 2015:
http://www.bbc.com/news/world-us-canada-34120247