Did y'all miss the point?
Focusing on the case, and what is, or is not a weapon was not the point, as I read it. I understood the point of the question to be whether or not the 2nd Amendment applies to States.
Short answer, it does not. The 2nd Amendment applies to the Federal Government. The milita clause, and the statement about the poeple's right are explanation for why the Feds shall not infringe that right.
Every state has in their state constitution, a section affirming the people right to arms. In some cases, it uses the language used in the Federal Constitution. In other cases, the language is similar, but different. That section of the State constitution is what is relevant to the state case, not the 2nd Amendment of the US Constitution.
And FYI, the story as I heard it was that hundreds of years ago, when the Japanese took over Okinawa, they banned the peasants from having weapons. Swords, spears, and bows. The Okinawans delveoped a martial art using the rice thresher (now known as nunchaku), because, since it was a farm tool (and needed to harvest the rice the Japanese ate) it was not banned.
All else being equal (and it almost never is) bigger bullets tend to work better.