"It is possible to be pro-gun and pro-gun-control. As a gun owner with a clean record and a sound mind, why would I oppose legislation that does not affect me but has the potential to keep guns out of the hands of those who pose a threat?"

1. Red flag laws.
2. "First they came for the socialists ... then they came for the trade unionists...."
3. Has the "potential?"  Now we're supposed to pass laws based on what we hope they might accomplish?  Laws have been overturned for being ineffective--recreational marijuana will probably be the next obvious example to make the history books--but we don't even have to entertain bills that have a reasonable expectation of achieving their intent with minimal side effects?  Well, I guess not; so much political posturing in Washington and the media is so ridiculous I doubt one person in twenty would believe a word of it if they got past how it makes them feel....
4. (added August 2020--can't believe I didn't think to include this originally) Being pro-gun and pro-gun-control just puts you in the same boat as politicians and celebrities who talk about how we really don't need guns, in a rather "let them eat cake" tone, but surround themselves with walls and gated communities and armed bodyguards.  That canard has been beaten to death, so I'm just going to leave it at that for you to chew on.