Well, we've been hearing the argument that our gun laws should be like those in Australia. In fact, the President himself mentioned it the day after the Charleston shooting. This is relevant to American politics.
The 1996 buyback cost around $300 million USD. The highest estimate I've seen places the number of guns turned in at 640,000. This is
actually a very small percentage, and more than half of the guns turned in were rimfire rifles.
The cost of such a thing here? Well, we have ~300 million guns. Let's imagine 10% being bought back. At a rate of $500 (which is the average of the Australian program), you're looking at $15 billion, minimum.
Did it work? It depends on who you ask and how the data is collated.
A study I've seen frequently cited [pdf] says no. Others have found slight decreases in the suicide rate with firearms.
"But they haven't had a mass shooting since Port Arthur!" comes the inevitable retort. There was
one at Monash University in 2002. Gun-control advocates say it wasn't a mass shooting because only two people were killed, but when they claim we've had 204 mass shootings in this country this year, they sure do count ones in which only two people were killed. Fair is fair.
There was
another shooting in South Australia in 2011 that killed two.
That's a small number, right? In 2000, Robert Long set a fire in a hiker's hostel that killed 15 people. In 2009, Brendan Sokaluk set a fire in Churchill that killed 9 people. In 2011, Roger Dean set a fire at a nursing home, killing 11.
Those numbers are still pretty low in comparison to us, right? Sure, but so is their population. At ~23 million, Australia has fewer residents than Texas. It's natural for numbers to be lower.