"dangerous and unusual weapons"
Prof. O'Shea's comment to a prior post led me to wonder: just what were the "dangerous and unusual weapons" that common law viewed as outside the right to arms? Everybody had muskets, pistols, knives, and before that bows and pole arms. For much of the period, no gentleman would go out without his sword. Blunderbusses, the equivalent of a sawed-off shotgun, were pretty common. Apparently private artillery was commonly privately owned (in the Heller briefing, an 18th century Boston requirement that guns, mortars and cannon be unloaded if stored indoors came up). Tom Jefferson had a pocket pistol specifically designed for concealed carry.
The only thing I can readily think of is the Infernal Machine, a generic term for various large assassination tools (i.e., wine kegs filled with gunpowder and surrounded with metal straps for fragmentation, or in one case, a huge 20-barreled gun), but even these were late in the period. (The bomb directed at Napoleon was what I remembered; he was saved by a drunken coachman who made the wrong turn, and didn't even awaken when the bomb detonated. He did have a reputation of being a sound sleeper, but that was a bit much).
Apart from that, I suspect the concept was "someday somebody may invent a dangerous and unusual weapon, and we could do something about it if they ever do."