That's nice. As in "Gee, I'm really glad they feel that way."
As much as we say the gun laws on the books arre unconstitutional, the fact of the matter is that it is going to take either judicial action declaring them as such, or legislative action rescinding them, for anything meaningful to happen.
A sheriff can declare that he is not going to enforce some law(s). All it takes is for the next highest level of law enforcement (the state police) to come in and enforce the law. The sheriff can jump up and down and complain that he is the highest law enforcement authority in his county/city, but until he gets a court to back him up it is all just bluster.
That all being said, it is important that these folks communicate with their legislators at both the state and federal levels instead of just making speeches at some convention of like-minded folks. They need the support of the voters when they do that.