First of, nice ad-hominem, secondly it's called democide and it's happened many times before (look @ Nero of Rome, or any other dictator), thirdly, your using a strawman, mixing satire with the argument. Let's make things clear for you; The government has weapons like fighter jets, of which you have no access to, that make your handgun useless, if the government wants to take over, they can do it even if you have your tiny pellet shooter on you.
Even then, (which I don't buy the argument that the constitution never said owning slaves was a right), but let's entertain the argument, your position that we can't change the constitution, means that in your worldview the 3/5 compromise still applies.
In 2016, the police used a warning shot, once in Sweden, no policeman had to fight off an armed attacker once. But by all means, keep living in your alt-right circle jerk, where you don't challenge yourself intellectually ever.