Ok, prior to the passage of the 14th amendment, the Bill of Rights only applied to the federal government. (Of course, the states had their own bills of Rights, most of which also guaranteed the right to keep and bear arms, and still do.) It was the specific intent of Congress in drafting the 14th amendment to extend the rights guaranteed by the Bill of Rights, ESPECIALLY the right to keep and bear arms, to the states. The problem was that the Supreme court of that time was a racist institution, and refused to enforce the 14th amendment as it's authors intended it to be enforced. This situation continued until the composition of the Court could be gradually changed over a period of many years. As this was done, the Court "incorporated" the Bill of Rights, gradually applying one, then another, of the amendments to the states. Our problem being that about the same time the Court abandoned it's racism, it started to be overtaken by anti-gun ideology. So the Second amendment never did get "incorporated", despite the explicit intent of the authors of the 14th amendment.
Menos, the relevant language in article 6 reads, "This Constitution, and the laws of the United States which shall be made in Persuance thereof; And all treaties made, or which shall be made, under the authority of the United States, shall be the supreme law of the land; And the Judges in every State shall be bound thereby, any Thing in the Constitution or the laws of any State to the Contrary not withstanding."
As I understand this, the order or precidence, from lowest to highest, is: State laws are trumphed by State Constitutions, which are trumphed by federal laws, which are trumphed by treaties, which are all trumphed by the federal Constitution. It would make precious little sense to write a Constitution which required state aproval to amend, but which could be overridden by treaties the states COULDN'T veto!
