[HoHoHoNowIHaveA]

Your premise is only applicable to US states.

It is not applicable to nation-states which demonstrate considerable effect in reducing gun-related homicides. Even more so when discounting individual lone-wolf attacks of a terrorist nature (Brevik, Norway).

I could post sources but they are beyond dispute at this stage. (United Kingdom, Japan, Australia and most of the Western world).

Evidence is also lent by the nation-states with lax gun control legislation which dominate the league table of gun-related homicides, of which, the USA is one.