Golden Hound,
I agree that his views on guns should have no bearing on whether you keep him as a teacher. I play piano and drums. I couldn’t have cared less about my teachers’ views on gun rights or any other important real life issue.
Most of the best musicians in the world are some pretty wild, reprehensible people. We forgive them because they play as if they have direct links to God. Yes, you may be able to find a bassist who thinks like Ron Paul. Then again, you'll probably have to resign yourself to playing like an average high school freshman.
You made a mistake by engaging him in such a controversial topic. You should have quickly scanned his stance on the issue, and then cut the conversation off by saying something like, "Honestly, Bob, I'm here to learn bass from you because I respect you for that; I'm not here to debate politics, religion or any other polarizing issues; I play bass to get my mind off these issues actually."
All is not lost. You will have more opportunities to stunt or redirect the conversation in the future.
Have you ever seen that quiet music student who's crappy at first but turns out to be phenomenal a few years later? I have. The student got good because he shut his trap, hunkered down and practiced. In no time, he passed up all the so-called talented musicians who got distracted by other things.
If you were me, you would stay focused on the music and would take advantage of this opportunity to become a good musician and nothing else.
Regards,
Jake