Ballot Box -- Jury Box -- Ammo box
If you are the only guy standing outside with your gun, and your neighbors are not with you, it is not time yet... go back inside and vote or sue.
Unless, of course, you're willing to die to be the spark that lights the tinder. I've got kids, somebody else can volunteer for that job, since you necessarily have to die to accomplish it, and there's always the chance that everyone else just says, "Meh." Hey, as long as someone promises that it makes us safer, how can I argue?
In all seriousness, if the government decides to ban firearms, it'll happen. Some standoffs will go down with people the media will portray as doomsday nutjobs, some citizens will be murdered in their homes, a few federal ninjas will die (as heroes, upholding law and order against those crazy domestic terrorists, of course), and the guns will be confiscated. I see nothing that makes me think that Americans, in general, would differ at all from 1930's Germans:
First they came for the
communists [gun owners],
and I didn't speak out because I wasn't a
communist [gun owner].
Then they came for the trade unionists,
and I didn't speak out because I wasn't a trade unionist.
Then they came for the Jews,
and I didn't speak out because I wasn't a Jew.
Then they came for me
and there was no one left to speak out for me.