How has the right to carry a gun affected the level of crime in the US?

Homicides involving firearms in the US are around triple the rate of the nearest rival. For comparison, homicide rates of any kind in the US are around double the rates of most other countries

• thus the proportion of homicide involving a firearm in the US is

a lot higher than comparable countries. While some rates of violent crime involving the weapons were higher, others were similar - this is not enough to indicate a direct link either way, but from the first part it is fairly obvious that more guns has lead to more people being killed by them.