"The US gun culture and the concomitant willingness to use guns against human beings are so widespread "

You throw criminals and ordirary citizens into the same pot. Ordinary Americans own guns because they fear the bad guys that may shoot them, not because they have an innate need to kill someone. There are lots of criminals out there, but they are concentrated in poor inner-city cores, along with their very disadvantaged socio-economic backgrounds. In other words, they have nothing to lose in order to survive. 

The solution to gun violence is to share the wealth and promote  economic development in poor areas, promote equal education, and provide a social welfare state. US capitalism is now corrupted by a corporate kleptocracy and US politicians are beholden to them. The tricke-down economy is just that: tricke down, fire hose up. The origins of gun violence in the US is economic disparity and until this is solved, passing gun laws is just waving the magic wand.