I mark the barrel and the nut with a sharp prick punch. All components must remain the same. Line up the 2 punch marks (witness) and then check with go/nogo gauge. Unless you miss by a full turn, you will be very very close. I was going to go the permanent nut attachment route, ie. red locktite or set screw, etc., but decided it would be too easy to change lug or something else and it negates the "nut".

Bill