The reality is that firearms are a "Pandora's Box" within the United States. There is no going back. The idea of a total ban resulting in a firearm free country ala the United Kingdom is largely delusional, and I don't believe that Australian style buyback would gel with the culture surrounding firearms and firearm ownership in the United States, and whilst I could see a world in which such a policy experienced limited success, I believe it would be just that - limited. That doesn't mean however successful policy couldn't be instituted. I think Switzerland is likely a model example of this, considering it's a country with a comparably robust gun culture yet has extremely limited amounts of gun crime. You could attribute this to the fact that Switzerland is just flat out a stronger country than the US when it comes to poverty and crime, but I also believe the sensible regulations on weapons there also play a large part. Many of the Swiss policies - Localized bureaus specifically tasked with administrating and monitoring firearms and ownership in their areas, tracking and regulating ammunition, bureau issued permits for ownership, etc all seem like perfectly fine regulatory legislation that would gel fine with the United States (Permits acting within the 2nd Amendment by gatekeeping most types of firearms, but not all). Whilst automatic rifles are certainly a flagpole issue of gun crime in the US, I'd say it would probably be more beneficial over all to target those policies towards handgun ownership as well. There is something to be said in that at least from my anecdotal experience, the United States has an (ironically) much more paranoid, fearful and "dangerous" culture towards guns compared to that of the Swiss. I can't imagine that sort of social mindset helps much, either.