This "nukes and nervegas" argument is easily disposed of by noting that the term "arms" (as understood by the drafters of the Amendment) clearly refers to the sort of weaponry carried by an ordinary soldier or officer in the field.
As noted earlier, this (not the "individual versus collective right") is the issue upon which the Court ruled in Miller.
I think that you narrow the protection needlessly. I see no indication whatever that our Founders meant to limit the arms protected. Private individuals could and did own the equivalent of warships at the time of our nations founding and the Constitution includes mechanisms for permitting the use of such arms during time of war.
The "arms" used to expel the government's navy from Boston Harbor were "stolen" from Fort Ticonderoga, a government stronghold, by the "militia" consisting of non-government rebels, and were dragged through the winter snows to surround Boston. To suggest that future generations would have no protection for owning such arms and would have to steal government arms is to misunderstand completely what our Founders had to accomplish.
It may be reasonable today to limit the arms, but it should require a Constitutional amendment to create such limitations.