Many people blame Americas problem with crime and violence on the gun. Many are just sadly uninformed. Whenever you are comparing two cultures and countries you have many complex factors to bring in.
People tolerate differences from themselves poorly.
So homogeneous cultures are likely to have less violent crime than heterogeneous cultures. The fact is that there are many issues of violence and crime are cultural. Many like to compare Japans gun crime to America as a way to vindicate their views on the gun control issue. I think it only demonstrates their tragic ignorance. Japan is one of the most homogenous and intolerant societies in the world.