In my case (if that’s what we are talking about) it’s not a barrel blank; it’s a factory tube I’d be rechambering. So the problem, if there is one, is that the reamer will follow the pre-reamed hole a.k.a. the old chamber.
This is where I was going with my comment. I was wondering if you could straighten out a non-concentric existing chamber with the boring bar, given you have enough meat on both sides to cut and not leave an oblong hole. After starting the chamber cut with a center drill and bit first, of course. Leave it a bit short of finished spec and use the finish reamer to complete the concentric final cut chamber. Seems like it would be a way to cut down on reamer deflection and reamer wear and still cut a really clean chamber.
It looks like my question was answered though. I'm hobbyist so I'm always trying to learn what I need to know to start doing barrels , chambering, threading , etc... by my own hand. Anyone can do the barrel tapering and cutting/crowning job but I don't trust myself to cut a shank properly yet and I still have to practice a bit at cutting threads. Seems like I can never get those nice, clean threads I see on some of these pictures of barrel threads and I'm not sure why. Even with brand new cutters and every thing set up properly I always get these very rough threads that would probably work, but bug the heck out of me....
