But some of the points raised, and terms used make me wonder if we are missing a point, on that might be important to theory, if not in practice.
The 2nd Amendment gives us NO rights. None of the Bill of Rights gives us any rights. We have those, irrespective of any written list. The whole Bill of Rights is a list of restrictions for the government, things they are not allowed to do to certain enumerated rights. And the listing of those rights is intentionally incomplete. It is stated so in the 10th Amendment.
I know we often talk of rights "granted" by the Constitution, but that is no more true than the belief that the US is a democracy. We are a democratic constitutional republic, and while democracy is a part of our system it is not all of it.
as to our "right" to over throw the government, I suggest a careful reading of the entire Declaration of Independence.
And, getting back to the question of "is it legal to tax a right", the simplest answer is that it is legal if the govt says it is. We may disagree on moral grounds, but the actual legality is determined by those who make, and interperet the law. There are many things that people hold to be moraly "right" but are illegal under current law. And many things that are legal under current law that some people hold to be morally wrong.
Historically, our govt has, and is taxing or regulating lots of rights. And, to date, I haven't heard of any successful challenges. So, I'd guess its pretty much a done deal. Nice to dream, though...
All else being equal (and it almost never is) bigger bullets tend to work better.