> What country is close enough to the US in size, heterogeneity and number of guns so that you can make a fair comparison?
In terms of number of guns, no other country is. That's the point: other countries made decisions and implemented policies to severely restrict access to guns, and the predictable result today is that there are far fewer guns and much less gun violence.
The decision to restrict guns is a long-term decision - it won't reduce gun violence overnight, but it will reduce gun violence over decades.
