Speaking about surplusage, why bother with the second amendent when Article I, Section 8, Clause 16 of the constitution already grants congress the power to organize and arm the militia? Are you saying a whole amendment to the bill of rights is mere surplusage? Or is it completely separate from Article I, Section 8, Clause 16 and affirms an individual right of the citizens to keep and bear arms- which the aforementioned clause does not?If the Second Amendment right "pre-exists the Constitution", then The Second Amendment is surplusage--Why have this right if everyone knew it exists?
If Article I, Section 8, Clause 16 has no effect--why have the Second Amendment since it would be surplusage?
Article I, Section 8, Clause 16 does not have effect--then it is surplusage.
Let me here call your attention to that part which gives the Congress power "to provide for organizing, arming, and disciplining the militia, and for governing such part of them as may be employed in the service of the United States--reserving to the states, respectively, the appointment of the officers, and the authority of training the militia according to the discipline prescribed by Congress." By this, sir, you see that their control over our last and best defence is unlimited. If they neglect or refuse to discipline or arm our militia, they will be useless: the states can do neither--this power being exclusively given to Congress.--Patrick Henry, Virginia Ratifying Convention, 5 June 1788 Elliot 3:51--52
Note that Henry is specifically addressing Congress's Powers under Article I, Section 8, Clause 16 and mentions them in this quote.
But, it's a right of the people.
This is law, not math, not science, not philosophy--one uses the rules of legal construction, not the rules of other disciplines.
The Second Amendment only addresses the concern expressed by Patrick Henry: "If they (Congress) neglect or refuse to discipline or arm our militia".
BTW, if you are going to talk about Occam's razor, which is a principle that generally recommends, when faced with competing hypotheses that are equal in other respects, selecting the one that makes the fewest new assumptions.
This is the solution which gives you that answer.