Of course a ban will not completely eliminate these weapons but it would reduce the supply and make it much easier for the police to seize the weapons so taking them off the streets. It would also be a step in the right direction in attempting to change public perceptions and amend the American attitude. It is understated just how relaxed American laws are in comparison to the rest of the world, even states such as Switzerland and Israel that are often highlighted by the NRA as being model states that allow gun ownership with few resulting shootings are much more restrictive than the USA. [1]  There is no reason to think that a black market is somehow going to result in more of these weapons being available so the fact that it will exist after a ban is not a reason not to go ahead with the ban. It is not ideal that a ban is not retroactive so leaving a large number of such guns in private hands but this number will slowly diminish over time rather than continuing to rise as it would under the status quo.  [1] Rosenbaum, Janet, ‘A League of Our Own’, Foreign Policy, 19 December 2012,