The simple facts are this happened in the UK and Australia and they both banned guns. Neither country has seen it happen since then. Coincidence? I think not. I appreciate the USA and their situation is very different, and the 2nd amendment and the constant misinterpretation of it doesn't help, nor do the NRA who in my mind are a criminal organisation that prey on peoples fears. But, the plain fact is that there is no need to own a fecking assault rifle or many of the military grade weapons you can buy in the United States, and not only buy them, but in supermarkets like Wal-Mart in plain view for all to see.
Polls show that the vast majority of American citizens want a change to the laws, and in time, with proper education, proper regulation, and gun amnesty, I have no doubt that this problem could be solved. However that is never going to happen all the time guns are glamorised by so many people and you even have morons like (at the time, Presidential Candidate) Ted Cruz saying he went out on Christmas Eve to buy a gun so if ISIS came to town he could defend his family. He's also the same moron who cooked bacon on his assault rifles barrel. Couple all that with extremely poor mental health treatment and a huge drug trade and you have a recipe for disaster, and in truth America at times, looks and behaves more like somewhere in the Middle East.
Everyone needs to get on the same page, and until the money comes out of politics that is never going to happen. The will is there with the people, unfortunately money talks, and too many people are getting paid to promote and keep gun laws as they are, when that stops, then and only then can you start to make a change.