Well yes, the barrel isn't my own construction and was originally made to have a press fit muzzle brake fitted. It can't be readily seen but
there's a cap pressed on to simulate what I believe we see in photos of the original prototype- a threaded cap in place of a muzzle brake
probably to protect the threads on the original barrel. I'm being sort of lazy and don't want to set up my lathe to cut some one off odd thread
on this thing and I don't think there's enough 'meat' left to cut a conventional thread but that was my thought as well.

It's like stepping through the looking glass. If I cut a thread, I can't just make a threaded muzzle brake, I'll have to make both the brake and the
locking ring that the original had so I can set the orientation of the brake baffles correctly, timing if you will. Not opposed to it but now you know why 1) I'm so slow
2) it takes me so long to build anything.

There it is.

Jerry