Mexico has a tight restriction on guns yet their murder rate is 23.7, Switzerland where every adult over 18 is issued a true assault rifle has a murder rate of 0.7. It is not the gun laws that cause problems it is the culture.
Mexico has tight restrictions on guns yet are flooded with guns from the USA. This effect is so severe that researchers have actually studied the effect on Mexican homicide rates from the lapsing of the US Federal Assault Weapons Ban, which had a ten year sunset rule.
Switzerland does have a lot of guns .... at home, as part of their military system. There is no culture of people carrying around guns with them in civilian life just in case they get randomly attacked for no reason. I live in Switzerland. I've not spent a huge amount of time in the USA, just visits over the years, yet I've seen there a bar with a "no guns" sign outside. This is something I have yet to encounter here.
But even if it is due to culture, you aren't going to turn the USA into Switzerland, so stop blaming culture (which implies that's how to fix it). Instead look to the UK, which has a culture far closer to America's. The UK experienced steadily growing gun crime rates for decades (graph on page 4), with very small occasional falls being quickly reversed by growth again. The big jumps in 1998 and 2002 are due to changes in counting methods - so you can mentally smooth the graph if you like. A few years after the UK passed much stricter gun control laws firearms offences started to fall dramatically and have continued falling every year.
I've noticed that UK statistics are frequently abused by gun rights advocates in the USA. Ways I've seen them be distorted include: chopping off the earlier years and then trying to claim that passing gun control laws made gun crime go up (it was going up anyway and the big jump was due to counting method changes), and claims that the UK has more violent crime than the USA (the category of "violent crime" excludes homicide, because the stats are collected through surveys and dead people don't reply to surveys, homicide rates are over 4x higher in America).
Something else to consider about the UK experience is that the stats cover up a lot of interesting detail, like the fact that whilst there are still firearms offences they are almost invariably committed with used guns and that provides a lot of evidence that can be used to bring the cases to resolution. "Clean guns" that have never been used before are exceptionally rare. In the USA they're the norm because it's so easy to buy new guns, so why leave a trail of evidence? Ammo is also hard to obtain. Some gangs have tried to make their own, but their home made ammo is far less deadly than professionally manufactured ammo.
I do not expect the USA to actually ever shift itself on the issue of gun control, even though it stands practically alone amongst developed countries. Instead American's who don't want to fear getting shot should simply leave.