I agree that banning firearms in the US would never happen, there are simply too many Americans that own them.
The problem is not really guns, in my opinion, something has gone wrong with society, guns were never a real issue when I was growing up, they were treated as tools and even the schools had shooting classes. No one ever considered shooting up a school or shopping mall so what has changed is us, and that is what we have to deal with.
Plus as I, and others, have said most gun violence is committed by people that had no legal right to own the firearm to begin with and if they use it for violence then they are not about to care about some gun law. Plus the fact that there are many Millions of firearms in society, those that own them legally are not going to turn them in, heck most would not even register them, so if you really cannot do anything about the firearms that would actually make a difference you have to deal with what is left, Criminals and those that have a Mental Illness that make them dangerous to those around them or themselves.