For argument’s sake, how about a nuclear weapon? If anyone can afford one, is it their right to privately own one?
Absolutely Yiu react with horror at the thought of your neighbor possessing a 50 megaton nuke but how likely is it? The market works here. And, thinking extraConstitutionally, how likely is it that an incredibly rich man would want a nuke? How likely is it that, outside of comic books a potential Joker would be able to control enough assets to buy a Bomb? Well, Hitler did the equivalent in his day, I suppose, but then, he got himself a State first. No laws would stop that guy if he arose in the USA because he takes control of the government before he gets the WMDS. His talents are political, not financial and rely on the destruction of constitutions for which no wording of an Amendment would be effective.
Those who could acquire Bombs by their wealth can better attain their desires, material and political, with the use of that wealth financially as with George Soros et al.
Most crew-served weapons can be operated by a single individual, and they can certainly be possessed and stored safely by an individual. And while leftists use made-up fantasies of being threatened by their neighbor having a belt-fed MG, they would only be in danger of its use, not its mere existence. The same can't be said for nuclear weapons.
Now, if one says we might need one to fight against an oppressive power, then the Constitution is pretty much moot at that point anyway, so use whatever you can get.
If that is what it takes..........
Or you can just do this.