If it got to the stage people were that unhappy with the government, I don't think they'd be looking for permission to fight back using violence. Check out Syria.

The sad thing is, people would no doubt go crazy if guns were banned. Probably just have to resign yourself to putting up with regular mass shootings and prey your not caught up in it. Your one of the sensible people who don't seem to believe that means tooling up with an assault rifle just incase though.