In addition to the other comments: have you considered that the causality is reversed?

That is, tough gun laws are enacted exactly because of a high rate of gun crime?

And of course those tougher laws can have at best a mild moderating effect when guns can freely enter that area with the tougher gun laws from other areas that do not have them.

https://en.wikipedia.org/wiki/List_of_countries_by_firearm-r...