There is a lot of talk about gun control right now because of the recent tragedy (and several other recent highly-publicized shootings). While I am generally in favor of some kind of increased regulation of guns and restrictions on what guns are available, I want policies that actually
work. I lack the specific knowledge of guns to have intelligent opinions on their distinctions [1] and I think most people are ignorant of what policies will have an effect and how much of an effect they will have. The US has a unique culture that cannot readily be compared to peer nations and there are significant political obstacles to doing good research on gun policy and doing epidemiological research on gun violence.
There are a couple of things I could say. The first is that the cat is, as it were, mostly out of the bag. There are a lot of guns in America and, unless we're trying to buy them back from people or forcibly taking them from people (fat chance), there will remain a lot of guns out there. The second is that, quite obviously, most gun control policy suggestions would not have stopped the tragedy which just occurred, nor would they be likely to stop some of the other mass shootings. If there are going to be positive effects, they will be on everyday gun violence - which accounts for far more deaths.
Again, the CDC has had its hands tied for the last 20 or so years when it comes to researching the causes of gun violence. The very first step should be funding more research. This shouldn't scare pro-gun advocates: it's simply research, and if taking guns away won't make us safer, we'll find that. If you really think that gun control is ineffective for curbing violence, then this would prove it.
One thing I do like and support is Cure Violence, formerly CeaseFire, which is an NGO that works within communities to treat violence like an epidemic. They've been rather effective, which surprises some. There is a documentary about them, The Interrupters, which I highly recommend.
[1]: I know the difference between a .22 and a .223, but I don't have any guns and will not ever purchase any guns (or, at least, will not have any guns in the house if I, for whatever reason, do purchase a gun someday).