It's barely debatable whether the RKBA's ~could~ be 'amended away'.
The Bill of Rights and the 14th Amendment make it clear that the peoples rights to life, liberty, or property are not to be infringed, abridged or denied, -- by any level of government in the USA.
Marshall made much the same point in Marbury, back in 1803:
"-- The question, whether an act, repugnant to the constitution, can become the law of the land, is a question deeply interesting to the United States; but happily, not of an intricacy proportioned to its interest.
It seems only necessary to recognize certain principles, supposed to have been long and well established, to decide it.
That the people have an original right to establish, for their future govern-ment, such principles as, in their opinion, shall most conduce to their own happiness, is the basis on which the whole American fabric has been erected.
The exercise of this original right is a very great exertion; nor can it, nor ought it, to be frequently repeated.
The principles, therefore, so established, are deemed fundamental. And as the authority from which they proceed is supreme, and can seldom act, they are designed to be permanent. --"
Thus, - as we see, the fundamental principles of personal liberty in our Constitution are permanent.
Any amendments that violated those principles would be null, void, and repugnant.
Of course, which is why it would be such an important debate. Imagine an actual nation-wide initiative to repeal/amend one of the BoR! Perhaps then Americans would have to finally come to grips with the fact that this is the country we live in, not some liberal fantasy concocted to assuage metros & women.