There is another spec out there, I guess. I’m no machinist either.Supposed to have a cut at the shoulder end of the threads, dimension C.
ETA:
I think. Again, I am no machinist.
A gunsmith I used said he liked what he called the AAC spec, in which there apparently isn’t a relief cut. He said he’d cut the relief if I wanted it afterwards if the suppressor had alignment issues. But all was fine…the suppressor’s are Banish 30 and Banish 223 and they both appear to have a relief cutout in their threads.
Heck if I know?
Not sure if this is the spec he’s talking about…some examples therein seem to have relief cuts, some don’t. Bah!