ilovettatt2 posted two tables of interesting statistics of gun violence. What is notable is that the countries with little gun violence are basically homogeneous societies, unlike the US which is heterogeneous. Moreover, the US has perhaps as many as 12 million persons in the country illegally. We have people here from all over the world, who come from different political structures, different cultures, and different belief systems. People don't change over night. It takes time and education, education that problems are solved through the ballot box and not by the gun. None of the other developed countries listed in the table have these particular problems in such great numbers as the US.
It should also be noted that the US has taken in, legally and illegally, large numbers of persons from the countries that are listed as nations with high rates of gun violence. These people need time to adapt to their new country and learn that political problems are solved through the ballot box and not by gun violence. So to be fair one must compare the US with a nation that has a similar population mix.
It would also be interesting to see the statistics for France, which is surprisingly not listed in ilovettatt's tables.
Stricter gun laws are merely a band aid on the problem. Though it won't solve the problem overnight, education and better access to mental health facilities are the way to a permanent solution.