Keep in mind, I chamber a barrel using a method that allows me to quickly, and accuratly, set them back up exactly the same way that I initially chambered it. That is very important if you plan on arriving at the same level of precision as you achieved the first go round.
The object is to get the chamber of the barrel running dead true again. I am assuming that the chamber was reamed dead true with the threads and action shoulder the first time.
Once you get the barrel set up, it is a matter of simply running the reamer in about .025 inch, which is what I do the first two times. Then, recut the shoulder to achieve the proper headspace, then re-cut the cone to it's proper dimension.
Most custom actions have about a 1/8 deep counterbore on the action ring, I usually do not have to mess with the threads. But, if you do, then you have to re-catch the thread and take that small amount to the shoulder. This is the reason I do not use a thread relief, I always have material to play with.
For what it is worth, on a 6PPC Barrel, I will set it back after 300 or so rounds, doing this twice, at about .025 each time. This simply freshens up the throat. After about 900 to 1000 rounds, I cut the entire body portion of the chamber off, and treat it like a new blank..
As you can see, the real trick is not the actual machine work, the trick is getting the barrel running the way you want it in the lathe. I have attempted to set barrels back for friends that were done elsewhere, and it sometimes make you wonder just what they trued up the first time.
Many think this is all a waste of time, because if you do not do your own work, the cost of sending it off, paying for the service might get a tad steep. But, if you do your own work, I do believe it is worthwhile. I can set one up and do what ever I have to in less than 45 minutes.........jackie
