nuclear weapons are illegal for some countries to own, so it doesn't take a loving genius to know that the law doesn't include them
if you wanna know what they ruled, just look it up. it isn't our job to explain amendments to people who think they're being witty
1) I googled "Second Amendment Supreme Court" and it has not yielded any official definition of "arms" by the supreme court. As far as I can see, it gives people the right to have handguns. Handguns? What the hell is a handgun? Wikipedia says: "A handgun is a firearm designed to be handheld, in either one or both hands." I don't know about you, but most men could hold an RPG in both hands.
2) Nuclear weapons were an example. Of course I don't think I can have a nuclear weapon in my backyard. However, since the 2nd amendment
itself is vague, it would
not be unconstitutional to keep and bear arms. Arms being weapons. Nuclear weapons being, you know, weapons.
A firearm that isn't unreasonably stupid.
Anything beyond that is up to other government bodies. But I can assure you it isn't vague.
That's also an undefined term. And I'm looking at the 2nd amendment at this second. I can assure you, it is vague.