Australia didn’t have a single mass shooting after they imposed strict gun control in the 90s. You’re just ignoring the evidence that’s right in front of you. Gun control works—period.
We've had to ask you this more than once before.
Gun control may reduce homicide rates somewhat, but the typical justifications for it are just bad statistics. Pointing out that Canada and Australia have gun control and much lower homicide rates, for example, ignores the fact that those countries had much lower homicide rates than the U.S. before gun control as well. Any analysis that ignores that basic fact is complete garbage.
Likewise, there is a correlation between gun ownership rate and homicide rate internationally, but that's driven in large part by the U.S. having so many homicides and so many guns. Gun ownership rates vary dramatically inside the U.S. too, but leaving out a couple of outliers (Louisiana and Mississippi), there isn't much of a correlation between gun ownership and homicide rates within the US: https://upload.wikimedia.org/wikipedia/commons/c/c6/Househol.... Five U.S. states have lower gun ownership rates than Canada and France, but all have higher homicide rates. Meanwhile, 9 U.S. states have much higher gun ownership rates than Canada and France, but similar homicide rates. If gun ownership rate was a dominant causal factor influencing homicide rates, you'd expect to see much higher correlations among U.S. states.
And even then, correlation is not causation. Higher violence may cause higher gun ownership rates. Or there may be other factors. What distinguishes Iowa from Louisiana, which have similar gun ownership rates but vastly different homicide rates? Or South Dakota and Mississippi, or Oregon or South Carolina, all pairs of states with similar gun ownership rates, but vastly different homicide rates?