Against my better judgement I’ll share what I do. The front ring is held in a fixture and I use straight mandrels in .0005” increments to indicate the centerline of the action that the bolt sees. I have used the Gretan mandrel and bushing methods but could never get repeatable indicating results that I was satisfied with, meaning I need to be able to strip it down and reindicate with the same result. I don’t like to remove metal unless I know it’s as perfect as I can get. I have never had an original thought and I give credit to Alex Wheeler for this method. Others might also do this, not sure. I have never tried the hand tools that are available. I get a very nice finish, lapping actually makes it look worse and is not something I do unless specifically directed to. When done the rear of the bolt needs to float with the lugs in contact.
