The laws are pretty old so I doubt there's reliable data. Australia has a clearer case. Firearm deaths definitely decreased after a 1996 law that pulled hundreds of thousands of weapons off the street. Rates were already decreasing before the ban but seemed to drop faster after. It wasn't a dramatic change and can't be directly attributed to the law.
I'll say this other thing though. Rates of violence aside, first world democracies that curbed gun ownership typically show better measures of development (for men and women) across the board. There was no slippery slope of lost freedom and government didn't suddenly oppress their unarmed citizens.
We are trying to get at causality here. Even in thr Australia case, I have to ask, did crimes committed by _illegally_ owned firearms decrease after the law? Much as we can productively debate who should or should not be allowed to own a firearm, I don't think there's much disagreement that there is some class of people who _shouldn't_.
I don't think it's possible to prove causality. But it stands to reason that decreasing the supply of weapons raises the price making it harder to acquire them legally or illegally. And the cost of making legal gun ownership harder seems to be minimal.
I'll say this other thing though. Rates of violence aside, first world democracies that curbed gun ownership typically show better measures of development (for men and women) across the board. There was no slippery slope of lost freedom and government didn't suddenly oppress their unarmed citizens.
https://www.rand.org/research/gun-policy/analysis/essays/199...