Despite having some of the world's toughest gun laws, around 250,000 unlicensed guns are estimated to be in circulation in Australia.
Australia's gun legislation is often held up as example the US can follow after a spate of shootings, most recently in Florida, where a lone gunman killed 17 people at the Marjory Stoneman Douglas High school.
In Australia, anyone caught with an illegal firearm outside the amnesty period could face a $280,000 (US$212,500) fine and up to 14 years in prison.
Some gun owners took the opportunity to surrender other weapons. These belonged to a former member of the Swiss Armed Forces and have been donated to a local museum.
Rocket launchers and machine guns
Of the 57,000 guns surrendered, almost 2,500 were either fully or semi-automatic. More than, 80,000 rounds of ammunition were also given up.
As well as a host of regular rifles and shotguns, the amnesty turned up several bizarre items, including a World War II Sten machine gun, Swiss cavalry sabers from the 1800s, an anti-tank rifle, and a rocket launcher.
This Sten machine gun had been partially deactivited but could have been modified to work once again, the report said.
Other items included a bolt-action rifle concealed within a spirit level, two tiny pistols the size of pens, and a homemade machine gun housed within a briefcase.
"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," said Angus Taylor, Australia's Minister for Law Enforcement and Cyber Security.
This Tower Enfield pistol was used by police in Australia before the introduction of black powder revolvers. It's been donated to a museum.
Supporters of the move pointed to both security incidents in Australia and mass killings in the US as a reason why the amnesty was needed.
Gun control success
Those statistics are often pointed to by gun-control advocates in the US as proof