Nobody proposed Australia like laws because they know there is not a chance they would go through. What did happen is that an Islamic terrorist attacked a nightclub with a gun. Instead of confronting the problem of Islamic terrorism they scrubbed his declaration of why he did what he did from the 911 transcript, then proposed legislation making it illegal for someone on the no-fly list to buy a gun. Guess what. This guy wasn't on the no-fly list. In other words the legislation would have no impact on the event that sparked it, except to deflect conversation from the actual problem.
I strongly agree that terrorists shouldn't be allowed to buy guns, but based upon how the no fly list has worked so far I would bet that all sorts of political opponents on the left would start showing up on that list if that legislation went through.
Personally, I don't own a gun and I don't want one. But if I had reason to believe that someone intended to harm me then I would want the right to legally get a gun because I know that in this country they will always be available to criminals. No legislation will ever change that.