I suggest that you go slow on the annealing, a case or two and test. I am pretty sure that an annealed case would have less neck tension, and some powders (133) seem to "like" neck tension. Recently I have tried a .263 neck to get back some of the brass that I had had to turn off to get where I want to be for loaded round clearance. So far, I like the change. I don't feel like I am in a marginal situation as I did with .008 neck thickness for the .262 chambers. As to being easier to anneal, if you mean less time in flame, and that time more critical to avoid dead soft necks, I guess you would be right. I am kidding. Thin necks would be super critical if you want to retain as much neck tension as you can, while improving uniformity of bullet seating force. I have done some annealing with a good machine for a friend, I picked it out for him, did the research on setup and helped him with that. We did what we wanted to, but they were much bigger cases, and their necks quite a bit thicker. For a short case, the issue of heat migration down the body of the case would be quite a bit more critical. Perhaps some sorting so that all the cases in a group and sighters feel the same would be a better way to go. Strangely, I have found that cases can become less uniform with use, and then even out in longer use. Has anyone else run across this. Perhaps they hit the maximum for work hardening. Years back, I knew a very good shooter who used a one piece FL die and expander to work his necks several times before turning. He said it was to make the inside surfaces of the necks more regular (more cylindrical, less "bumpy'). I wonder if a similar setup could be used to run a test on some cases to see if repeated sizing and expanding would bring them up to the same hardness after a number of cycles. I think that the trick would be to keep the amount of both within smaller limits than is usual with unturned necks and the usual one piece dies.
