Friday's shooting at Santa Fe High School in Santa Fe, Texas seems bound to kick off another national conversation about gun control. There will almost certainly be more debate about whether it would even be possible for the US to limit its millions of privately held guns, by far a higher per capita gun ownership rate than any other country.

It is worth considering, as one data point in the pool of evidence about what sorts of gun control policies do and do not work, the experience of Australia. Between October 1996 and September 1997, Australia responded to its own gun violence problem with a solution that was both straightforward and severe: It collected roughly 650,000 privately held guns. It was one of the largest mandatory gun buyback programs in recent history.

And it worked. That does not mean that something even remotely similar would work in the US — they are, needless to say, different countries — but it is worth at least looking at their experience.

What Australia did

On April 28, 1996, a 28-year-old man with a troubled past named Martin Bryant walked into a cafe in Port Arthur, a tourist town on the island of Tasmania, and opened fire with a semi-automatic rifle. He killed 35 people and wounded another 28.

Australia's prime minister at the time, John Howard, had taken office just six weeks earlier at the head of a center-right coalition. He quickly drew a very clear conclusion from the Port Arthur killing: Australia had too many guns, and they were too easy to get.

"I knew that I had to use the authority of my office to curb the possession and use of the type of weapons that killed 35 innocent people," Howard wrote in a 2013 op-ed for the New York Times. "I also knew it wouldn’t be easy."

Howard persuaded both his coalition and Australia's states (the country has a federal system) to agree to a sweeping, nationwide reform of gun laws. The so-called National Firearms Agreement (NFA), drafted the month after the shooting, sharply restricted legal ownership of firearms in Australia. It also established a registry of all guns owned in the country, among other measures, and required a permit for all new firearm purchases.

One of the most significant provisions of the NFA was a flat-out ban on certain kinds of guns, such as automatic and semi-automatic rifles and shotguns. But there were already a number of such guns in circulation in Australia, and the NFA required getting them off the streets.

Australia solved this problem by introducing a mandatory buyback: Australia's states would take away all guns that had just been declared illegal. In exchange, they'd pay the guns' owners a fair price, set by a national committee using market value as a benchmark, to compensate for the loss of their property. The NFA also offered legal amnesty for anyone who handed in illegally owned guns, though they weren't compensated.

There were fears that the mandatory buyback would provoke resistance: During one address to a crowd of guns rights supporters, Howard wore a bulletproof vest. Thankfully, fears of violence turned out to be unfounded. About 650,000 legally owned guns were peacefully seized, then destroyed, as part of the buyback.

According to one academic estimate, the buyback took in and destroyed 20 percent of all privately owned guns in Australia. Analysis of import data suggests that Australians haven't purchased nearly enough guns in the past 18 years to make up for the initial decline.

Australia's program saved a lot of lives

In 2011, Harvard's David Hemenway and Mary Vriniotis reviewed the research on Australia's suicide and homicide rate after the NFA. Their conclusion was clear: "The NFA seems to have been incredibly successful in terms of lives saved."

What they found is a decline in both suicide and homicide rates after the NFA. The average firearm suicide rate in Australia in the seven years after the bill declined by 57 percent compared with the seven years prior. The average firearm homicide rate went down by about 42 percent.

Now, Australia's homicide rate was already declining before the NFA was implemented, so you can't attribute all of the drops to the new laws. But there's good reason to believe the NFA, especially the buyback provisions, mattered a great deal in contributing to those declines.

"First," Hemenway and Vriniotis write, "the drop in firearm deaths was largest among the type of firearms most affected by the buyback. Second, firearm deaths in states with higher buyback rates per capita fell proportionately more than in states with lower buyback rates."

There is also this: 1996 and 1997, the two years in which the NFA was actually implemented, saw the largest percentage declines in the homicide rate in any two-year period in Australia between 1915 and 2004.

Pinning down exactly how much the NFA contributed is harder. One study concluded that buying back 3,500 guns per 100,000 people correlated with up to a 50 percent drop in firearm homicides. But as my colleague Dylan Matthews points out, the results were not statistically significant because Australia has a pretty low number of murders already.

However, the paper's findings about suicide were statistically significant — and astounding. Buying back 3,500 guns correlated with a 74 percent drop in firearm suicides. Non-gun suicides didn't increase to make up the decline.

There is good reason why gun restrictions would prevent suicides. As Matthews explains in great depth, suicide is often an impulsive choice, one often not repeated after a first attempt. Guns are specifically designed for killing, which makes suicide attempts with guns likelier to succeed than (for example) attempts with razors or pills. Limiting access to guns makes each attempt more likely to fail, thus making it more likely that people will survive and not attempt to harm themselves again.

The buyback also may have reduced the rate of mass shootings. A 2018 study found that, in the 18 years before Port Arthur, Australia experienced 13 mass shootings; in the 22 years since, the country has only suffered one such incident.

Bottom line: Australia's gun buyback saved lives, probably by reducing homicides and almost certainly by reducing suicides. Again, Australian lessons might not necessarily apply to the US, given the many cultural and political differences between the two countries. But in thinking about gun violence and how to limit it, this seems like a worthwhile thing to look at. If you're looking for lessons about gun control, this is a pretty important one.

Watch: 18 charts that explain gun violence in America