You can also consider that in the United Kingdom, homicide and violent crime were at very low levels when one did not even require a police permit to legally acquire a standard shotgun (before 1967). As the laws there got even more strict during the 1980s and 1990s period, homicides and violent crimes continued to increase at rates far higher compared to before 1967.
They were even lower before 1920, when you could buy a gun, including machine guns, across the counter in England. No registration, no permits to own or carry a gun.
And crime was much lower than it is today.
All documented in the wonderful, scholarly work of Professor Joyce Lee Malcolm.