Anyway, no one's talking about a plan ala Australia just yet. For one thing, I doubt they had a Constitutionally protected right to arms. We might one day fairly soon -- if not right now -- reach some kind of 2/3rds majority by population for strict gun control legislation in this country, but you're never going to get the 38 states it takes to ratify it. Not in the next 50 years, anyway.
The only way anything drastic is going to get done is by having majority of Supreme Court justices who believe the operative phrase in the 2nd amendment is not "shall not be infringed" but rather "well regulated." And even then... the Court is very cautious to lag behind public opinion on these matters so as to maintain their place as an unbiased legal arbiter. Even a justice like Elena Kagan, who is quite openly disdainful of a broad reading of the 2nd amendment, would be likely to tread carefully on behalf of judicial restraint.