Universal background checks and closing every loophole is pretty much all we can do apart from removing 2nd amendment (I personally 100% support it). Will it stop mass shooting, of course not, but it should drastically reduce them. If every citizen would have to go through similar process that we have in NYC, people would be thinking twice about each additional fire arm they purchase. As a compromise we can demand concealed carry across all 50 states.
That's all we're asking to even consider, but gun owners be like: