2"? Anti-tank? :naughty:

Threading is probably between centres, chambering will require an independant chuck, self centreing isn't accurate enough.

The big unknown is the hardness of the steel and you probably want to thread up to a shoulder which is an extra complication especially if you want barrel furniture to line up. You'd probably have to adjust the shoulder after cutting the thread unless you were very good.

Some steels are a toad to thread cleanly, the metal tending to tear and gall if you aren't grinding. OTOH it must be possible but you need to talk to someone who's actually doing it. Google it and find some helpful American prepared to spill the beans. It's probably all comes down to the tooling.

For an accurate thread I'd usually screw cut it on the lathe, slightly shy of the final thread size to get the pitch right, then run a die to finish it with buckets of anti-gall lube. OTOH, if they can button rifle this stuff maybe they can roll the thread, not something I have ever done

Robin