Morality and rights are -in a democracy- a consensus of opinion, and what is written in the law (including the Constitution). All of which is subject to change/revision through whatever processes are described in the laws.

I would disagree. I think you're conflating concepts - morality, opinion, rights, and laws - that are subtly and importantly different from each other. Something can be legal but immoral; a society can have a legal requirement that deprives people of fundamental human rights; people can form a consensus of opinion on what they believe is moral and can still be wrong. One need not posit a creator in order to identify universal human rights that it is wrong for any society to violate. A country that commits genocide against a religious or ethnic minority isn't acting morally or consistent with that minority's rights just because the genocide is sanctioned by duly-adopted law.

To try to keep nominally on the point I was trying to make, though, it's pretty clear that the "right" to gun ownership is not a fundamental or natural or universal human right. Some rights are simply decisions made by one society to resolve a particular issue in one way or another - such as our right to be free from quartered troops. At most (and it is disputed) we have chosen to adopt for ourselves a guarantee of the ability to own firearms. But contrary to Dope1's assertion, that is neither a fundamental or natural right.