If you look at rates of violence over time, the gun laws you're talking about had no effect. Violence continued to decrease at the same rate it did before.
It is extremely challenging to look at gun violence/firearm homicides in Australia, because the numbers are already so low that drawing statistical correlations is difficult if you're being responsible.
That being said. America, 300M people. 19,000 firearm homicides last year. Australia, 20M people, 27.
That being said. America, 300M people. 19,000 firearm homicides last year. Australia, 20M people, 27.