Registration of some kind would be advantagious, since it is a form of proof of transfer. I'm really not sure how it is that the government would work the logistics of disarmament. Any time you transfer a gun, there is no way to control it's course after the sale. I guess it would be akin to selling a car to someone who decided to operate under the influence and kill someone, why worry about it? The car, of course, IS registered, and the police would never notify a prior owner that his one-time vehicle was involved in a fatal crash. The system records only FFL sales, so law enforcement is forced to start by suspecting the last recorded owner. I do think that regardles of the legal ramifications, requirements, etc..., if you choose to sell a weapon, you have a serious responsibility to ensure that they are responsible, stable, and aren't in a desperate condition that could lead to tragedy. I tried to sell one of my AR rifles, and gave up, as I was not able to find a buyer who had a healthy attitude about the gun, just lots of guys who wanted to have something that would force others to fear/respect them.