The problem with the cartels is the other way around: They are illegally importing guns which been sold legally in the US into South America, where they outgun

The problem with the cartels is the other way around: They are illegally importing guns which been sold legally in the US into South America, where they outgun local police forces. That's why lax US gun legislation isn't just a national matter. I don't think there is a solution for the small-time criminals having access to guns, all you can do at this point is try and drive the black market price up, by making it tougher to get new guns. Either problems require new legislation, which the gun lobby is blocking at every step of the way.