First, regarding muskets, recall that government's best tech was the musket. Since the right of free people to defend themselves is the basis for the Second Amendment, it is necessary that the right to possess arms reflects adequately the technology progression.
If civilians have similar arms to government, government is necessarily restricted to that to which it's subjects are willing to tolerate. When government--or any gang of thugs--possesses significantly more effective weapons than it's subjects, that government inevitably devolves into tyranny.
We see this happening now across the EU.
Free Tommy!
Ah well that makes sense. If the thugs/government is going to come at you with muskets, you defend with muskets. If, 200 years later, they are going to come at you with AR-15s, then you have the right to bear that.
Never occurred to me thanks!