I understand that on preban ar you can throw whatever you want on it. However with a post ban ar you need to have the comp/muzzle break pinned, welded, etc so that the "barrel" threads are covered. Is there anything saying that you can not have quick detach threads on the comp/break? Or once it is pinned/welded it is considered part of the barrel thus needing to be covered as well?
What do you mean by quick detach threads? If you're talking about lugs, like something resembling the HK-style 3 lug system, or the surefire lug system, those are not threads/threaded barrels. If it screws on on allows something to be screwed on (eg, threaded) then it counts as an evil feature.
-Mike