The people at my office just don't get it. They snicker and sneer about how "paranoid" I am because I think people should be able to carry a gun. They laugh and joke about the idea that they might need to protect themselves someday from an oppressive government...DJK shares an experience we've all probably been through--dealing with our convictions at our places of employment.
Some are more open and accepting than others, but a rule I established for myself long ago always worked well for me: I was there to work. Some can mix the personal and professional seamlessly. I've never been one of those.
If a co-worker challenges you on guns, I'd have two responses ready:
If I thought they were a jerk just trying to bust my chops, I'd let them take their shot and tell them I didn't think it appropriate to debate politics on company time.
If I liked them, I'd tell them work wasn't the place to discuss things, but if they'd like to go to the range some time...