I think that changes in culture are usually more powerful than top down changes in law. Reducing consumer demand for oil, versus outlawing oil production.
A similar idea can work for reducing gun violence as well. A cultural change means less guns and less anger in American society. That's what we need, which may sound idealistic.
Changing the law can help, but it's secondary. I'm in favor of more stringent legislation about gun ownership, but I think it wouldn't be a magic bullet; speaking of bullets. Cultural change so there are less guns floating around in society is the main need.
I think overall murder rates, on a per capita basis, are lower now than in decades past, but we seem to hear more about mass shootings these days. I wonder if that has to do with a greater proliferation of semi automatic weapons in recent years?
Laws, could change that, to some extent. It's crazy to allow so many high powered weapons in our society. On the other hand, now there is the worry about things like home made weapons from 3D printing which folks can use to get around the law. Again, a change in culture is what we need most.