My intent was to have a funny response to the obviously hostile. When someone approaches you with a blatantly gun-hater attitude, it's easy to be confrontational and want to kick their ass with words, so to speak. We know our position is based on truth and logic. But we often fail to realize that the overtly hostile don't care about reason or truth. I think it's better to be funny. You'll never convince them, but someone ELSE might overhear.
Consider your audience in that kind of engagement to be everyone else, and the anti is just a prop. Use them against themselves. Demonstrate yourself to be the opposite of what they are trying to imply. Its a good opportunity if you realize that's what it is. Normally you have a conversation with one person, and you may give them something to think about. But if an anti gets in your face, they just got everyone's attention who is nearby. You could give a whole room something to think about, much to the chagrin of the douche with the chip on their shoulder.
I often add analogies. "I have a penis, are you afraid I'll rape you?" "I'm wearing pants, are you afraid I'll moon you?"
This is used as bait to lead them into the 'you're doing it because you have a small dick' thing. Which results in "Regardless of how large or small it may be, it is not an adequate self-defense too. I find it very disturbing that you relate weapons and sex, and fear a rational conversation with someone so deeply disturbed may be impossible."