The USA is the only developed country which shows up in the list of the 50 cities with the highest murder rates in the world https://en.wikipedia.org/wiki/List_

The USA is the only developed country which shows up in the list of the 50 cities with the highest murder rates in the world https://en.wikipedia.org/wiki/List_of_cities_by_murder_rate https://en.wikipedia.org/wiki/List_of_cities_by_murder_rate It matters because guns are more effective at killing people. You easier kill someone with a gun than with anything else which makes criminals more likely to do it. My guess is that there is indeed a correlation between availability of weapons to criminals and murders. There are also other ways of obtaining weapons for criminals: From the military, which you see for instance in eastern europe. Or from other countries with lax weapon laws, like most of the Americas get their weapons from the US. The USA does not even need to outlaw weapons, but it certainly needs better regulations.