Is there X amount of mass shootings that would change gun supporters' minds, or is that the wrong way to think?

Isn’t hunting a bit of a red herring? If you’re hunting to put food on the table a single shot hunting rifle is adequate. There could be, for example, legislation that prohibits ownership of large magazine semi-automatic rifles while permitting the ownership of hunting weapons. Can you still kill lots of people with a single shot rifle? Yes, but it’s not as easy.