First of all, getting into an argument with someone who (for whatever reasons) has strong anti-gun views and opinions is usually a waste of time. Therefore I avoid any confrontation unless they attack my position first, especially in a group conversation where others are present that might be more open minded. Then I try to use logic and facts to oppose emotion. I have found that occasionally a dedicated, anti-gun individual will come looking for me with a different attitude after something traumatic happens in their lives. Otherwise they are best ignored. After all, ignorance is bliss.