The Bill of Rights is NOT an inclusive list of The People's Rights. In fact, the original idea of the Constitution was to only have a list of the specific Powers of the Federal Government. It was understood that every other Power would be reserved by the States and The People.
The anti-Federalists didn't like this arrangement of an "implied" understanding. Consequently, they demanded that an explicit list of Rights (modeled after Great Britain's "Rights of Man") be included in the Constitution. It was not ... but a promise was made to address such a list of Rights (as amendments) only if the anti-Federalists would ratify the Constitution as-is.
The anti-Federalists kept their promise and ratified the Constitution. However, during the First Congress, the Federalists threatened to go back on their promise by simply ignoring the pleas of the anti-Federlists (who were in the minority by a long shot).
If it weren't for James Madison (a Federalist), we may never have had a Bill of Rights. Madison was wise enough to know that the symbolic gesture towards the anti-Federalists (of keeping a promise to address their concerns) was more important than the end product. Madison, like most Federalists, continued to believe that a Bill of Rights was unnecessary. But he entertained the consideration of an enumeration of Rights in order to help keep the infant republic together.
The Federalists despised Madison for doing this, but in retrospect it was the right thing to do -- i.e. the right thing to do in order to help keep the early nation together. However, the Federalist concerns over a Bill of Rights were quite valid and have been borne out over time.
Specifically, the Federalists had two problems with a list of Rights:
And indeed, the Federalists would be right. The original understanding of our Form of Government was as follows:
Federal Government Powers -- Unless Specifically Permissible (listed/enumerated), It is Prohibited.
The People's Rights -- Unless Specifically Prohibited, It is Permissible.
...contrast that with today's practical understanding of the scheme of things (inverted):
Federal Government Powers -- Unless Specifically Prohibited, It is Permissible.
The People's Rights -- Unless Specifically Permissible (listed/enumerated), It is Prohibited.
And the Bill of Rights plays right into the modern lie of the Federal Government "giving" the people a list of what is "specifically permissible."
So, how does this relate to the Second Amendment?
Even if the Second Amendment implied a collective (State) right (which it doesn't), it wouldn't matter.
Why? Because the Bill of Rights is NOT an inclusive list of The People's Rights.
Individual gun ownership would be a Right retained by The People even if the Second Amendment did not exist by virtue of the fact that the enumerated Powers of the Federal Government does not give the Federal Government the Power to restrict/prohibit that Right. In other words, we come full circle to the original Federalist argument against a list of Rights. As they warned would happen, such a list of Rights has been turned against us -- i.e. such a list is now interpreted as being inclusive and complete (i.e. comprehensive).