Gun control

In 2013 a bill was introduced in the senate to ban assault weapons and it was defeated by a vote of 60 to 40. At that time the democrats controlled the senate with 55 democrats and one independent. The vote was 44 republicans against, 15 democrats against and one independent against. There are an estimated 10 to 15 million assault rifles in the country and there was a ban on these weapons for ten years from 1994 to 2004 and not one of these weapons was collected by the government. They did not try to collect these guns because the back lash would have been political suicide. For those who are anti-gun consider this possibility. Say anti-abortion people want to ban abortions the day before delivery. The fear is that if that is allowed the next step will be a week before delivery. Gun advocates feel if the government wants to collect one type of gun the next step is to collect other guns. If the country could agree to ban assault weapons what would be done with the 10 million that are already in the hands of the public? If by some miracle these guns could be kept safe, would a potential mass killer change his mind because he could not get an assault rifle?