Gun related suicides are the real problem (~20,000 out of the total ~30,000 annual USA gun related deaths). Nobody is focusing on that issue.
If the US had the same amount of gun violence in a day that the UK experiences in a year, it would be worldwide news.
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.