Anything is "useful" to a militia. But the question was whether Miller's weapon was one that would be used by average Militia member to take into combat and be effective.
I don't think his weapon would have qualified. In my opinion. We'll never know.
"We'll never know"??????????????
You mean you'll never know.
The term "shall NOT be ingringed" pretty much covers whatever one can use to accomplish what one needs.
You haven't answered where the state militia's are.
Where are they?
The 2nd doesn't say anything about "useful to" or "reasonable relationship to". It just says "arms" and "shall not be infringed". Congress is therein forbidden from limiting terms.