As more U.S. companies were showing support for stricter gun laws this week, two foreign governments announced Wednesday that they had made significant progress on restricting access to firearms.

In Australia, authorities revealed that citizens had handed over 57,000 illegal firearms between July and September last year during a gun amnesty. In total, more than 35,000 rifles and more than 12,000 shotguns were turned in, among other firearms.

Meanwhile, the Norwegian government now appears to have a majority for its plan to ban semiautomatic rifles — similar to those used in a string of deadly mass shootings in the United States — by 2021, despite protests from farmers and hunters.

If passed, the Norwegian law would classify previously legal rifles used by hunters as “military-style” weapons. It would be accompanied by other measures, such as upgraded background checks before handgun purchases, according to Peter Frolich of the Norwegian parliament’s judicial affairs committee, who spoke to the Associated Press.

Both initiatives indicate the lengths to which governments have gone in response to mass shootings in their respective countries.

Australia’s firearms amnesty is based on a nationwide scheme that followed a mass shooting at a tourist site in the country in 1996 that left 35 people dead. At the time, the Australian government decided to buy back firearms and strengthen gun-control laws, managing to significantly reduce the number of weapons in circulation.

The Australian measure is based on the assumption that any reduction of the number of available weapons that could fall into the wrong hands can help prevent shootings -- and there is some statistical evidence for this. In his study published in 2016, “Public Mass Shooters and Firearms: A Cross-National Study of 171 Countries,” University of Alabama's Adam Lankford, an associate professor of criminology, found a link between the number of guns and mass shootings that killed four or more people. The data set ranged from 1966 through 2012.

Since 1996, countries including Canada, Britain and Norway have tried out modified versions of Australia’s measures, allowing owners of illegal weapons to hand them in without fear of legal repercussions.

Gun control advocates are pushing for an assault weapons ban in the wake of the Florida shooting. Here's a breakdown of the heated arguments around a ban.

In Norway, lawmakers’ willingness to reduce the number of firearms in circulation can mainly be traced to the 2011 Utoya shooting, in which a right-wing gunman, Anders Behring Breivik, killed 77 people in one of Europe's most gruesome terrorist attacks. Most of the victims were children or teenagers. One of the weapons Breivik used was a semiautomatic rifle.

Since then, the Norwegian government has pondered the feasibility of a much broader ban of semiautomatic rifles than is in place elsewhere. A commission proposed such restrictions last fall, and lawmakers are now set to approve the measures.

In Australia and in Norway, two major shooting massacres appear to have changed the national debate over gun ownership, but both examples also show the limits of such approaches in the United States. Gun amnesties on illegal firearms naturally worked only if certain types of firearms were banned or their access was limited.

“Taking these unregistered firearms off the streets means they will not fall into the hands of criminals, who might use them to endanger the lives of innocent Australians,” Law Enforcement Minister Angus Taylor said Thursday.

But based on numbers provided by Canadian authorities, amnesties mostly help to reduce the number of illegal firearms accidentally inherited by daughters or sons of gun owners. Hence, such initiatives are ill-equipped to directly combat illegal weapons ownership among criminals or individuals willing to commit attacks.

To prevent massacres, amnesties tend to work only if deployed in tandem with the European-style measures deeply loathed by American conservatives: broad bans or restrictions on firearms ownership.

“In the United States, of course you have the gun lobby and the Second Amendment,” said Anders Romarheim, associate professor at the Norwegian Institute for Defense Studies and an expert who advised the commission looking into the Utoya attack. “But in Norway, we don’t really have anything similar to that. So, once the idea came up to restrict firearms access, it was a done deal.”

More on WorldViews: