Folks on both sides of this conflate the RKBA with the 2A. I think we all know that the 2A doesn't confer, conger or create a right out of some idea or agreement among the Founders. As I understand it, the 2A was intended to protect the RKBA, an inherent and preexisting right, from government. The essential spirit of the Bill of Rights was to limit the reach of government.
Did the Founders imagine we would have machine guns, under-barrel grenade launchers and nuclear weapons? I have no idea. The detailed descriptions for the militia list arms matching what typical soldier would carry. The various militia acts have covered that their are both an organized and an unorganized militia. No where for the first century of US history are their laws on the books that totally deny an individual RKBA.
IMO individuals' rights were to be expressly protected both to the ends of self and state protection. In its wisdom and political evolution government today has found a way to imbue our standing military with the idea that they are not special, not above the law and that they are among the citizenry in general. In the 18th century British troops were doing the bidding of the British Crown. Our Founders sought to prevent such a military here.
Historically the line between standard military arms such as shoulder fired rockets and civilian semi-auto rifles and handguns has moved as to what is permissible/legal. A hundred years ago hardware stores sold Thompson submachine guns. That no longer happens. Case law and state and federal laws have clearly delineated civilian arms.
Many things stop people from obtaining firearms from licensed dealers. I've said here on this site that private sellers should at least have a means of getting a background check for a prospective buyer. Universal background checks would be a good step in the quest for keeping guns out of the wrong hands. That would be worth a compromise like taking suppressors off the list of NFA weapons. A suppressor is not a silencer. A 117+ db noise is anything but quiet. It's worth the trade off. As a comparison, modern testing on a selection of handguns has shown that they produce 156 to 168 dB when firing without a suppressor, and 117 to 140 dB when firing with a suppressor.
So 'arms is all it says' leaving it to the legislatures and courts to interpret. I infer that explains the reference to "animating contest for freedom" written about by Sam Adams.
Have a great holiday week.