Your gun problems in the US appear to be not so much about "criminals" using guns as it's about random ordinary people under influence of stress or propaganda shooting ordinary people. Having a legal firearms market with ready availability makes it demonstrably easier for such characters to acquire firearms and shoot people vs. other developed economies.
Criminals in contrast in most jurisdictions (except notably in Mexico) tend to want to limit violence and fly under the radar and tend to use firearms as a last resort.
Criminals in contrast in most jurisdictions (except notably in Mexico) tend to want to limit violence and fly under the radar and tend to use firearms as a last resort.