Here’s the deal with the Australian gun control law that Obama is talking about
In an interview with comedian Marc Maron that aired Monday, President Obama cited Australia's gun laws as an example the United States should follow. Australia established strict gun control in response to a massacre in Tasmania that left 35 people dead in 1996. Since then, Australia hasn't witnessed any mass shootings.
So what have the Australian laws actually done for homicide and suicide rates? Howard cited a study by Andrew Leigh of Australian National University and Christine Neill of Wilfrid Laurier University finding that the firearm homicide rate fell by 59 percent, and the firearm suicide rate fell by 65 percent, in the decade after the law was introduced, without a parallel increase in non-firearm homicides and suicides. That provided strong circumstantial evidence for the law's effectiveness.
The paper also estimated that buying back 3,500 guns per 100,000 people resulted in a 35 to 50 percent decline in the homicide rate, but because of the low number of homicides in Australia normally, this finding wasn't statistically significant.
What is significant is the decline the laws caused in the firearm suicide rate, which Leigh and Neill estimate at a 74 percent reduction for a buyback of that size. This is even higher than the overall decline in the suicide rate, because the gun buybacks' speed varied from state to state. In states with quick buybacks, the fall in the suicide rate far exceeded the fall in states with slower buybacks:
http://www.washingtonpost.com/blogs/wonkblog/wp/2015/06/23/what-happened-after-australia-banned-lots-of-guns-after-a-massacre/