Nice, simple, easy solution.
Slight issue though — Monash University in Australia saw a mass shooting after the ban. Seven shot, two dead.
Then there was the siege of a coffee shop in Sydney.
But before either of those, there was the academic research carried out by the British Journal of Criminology that found that the decline in gun crime in Australia had been in decline from before the ban and that the rate of decline was unchanged by the ban (there are other studies as well which followed that one, none of them American, which agree with that finding).
But before that there was the statement by the head of the Bureau of Crime Statistics and Research in Australia, who said “I would need to see more convincing evidence than there is to be able to say that gun laws have had any effect” (and that was almost a decade after the ban).
However, and this is the good bit of news, all the research carried out and all the experiences of the people involved in this in both Australia (where they introduced a ban) and New Zealand (where they didn’t, but saw the same decline in gun crime) says that they know how to tackle gun crime — but it’s by funding their police forces and tasking them with tackling the problem rather than bringing in gun bans. And the UK then reinforced that lesson by bringing in gun bans several times without reducing gun crime (it in fact increased and then accelerated that increase) or preventing further mass shootings; and then they funded their police to tackle the problem (at which point the rate slowed and then the trend reversed and it started to decrease).
Simple, feel-good, intuitive ideas are nice, but if they don’t match actual data… well, you know what Feynmann said about that…