But with an expander ball the seating force would be decreased because the expander expands the neck brass outward, and with less springback due to annealing, the brass would spring back less inward
With a bushing die sans expander or a Lee Collet there would be more seating force due to the sizing operation sizing the brass inward and then less springback outward leading to a smaller ID
Correct?
Well, I don't know the answer, but I agree with your logic. I agree that this thread is great food for thought.
I have stayed with my ball expander. I leave it loose, and out of my forster co-ax press, it certainly should not disrupt the symmetry of the case while sizing. (the co-ax allows the dies to move some as well).
But I am considering annealing. I've neck turned in the past, but never saw an improvement.
I am contemplating this sequence as a possible theoretical "nirvana":
1) Resize after firing with a body only die, taking about 2 thousands back off the shoulder. Leave the neck in fired state.
2) Use an inside neck reamer, custom cut to reflect the guns chamber neck, minus about .028 (2x .0014). This should knock out any donut or bad thick spots.
3) Anneal. The expensive units are good I suppose, but Tempilaq 750 and a pair of opposed torches and a "spinner" on a drill where I can drop the case out of the flame the instant the tempilaq melts should work.
4) Collet resize, versus bushing resize, based on what you can get. Would aim to use bushing to go about .004" less than bullet. Springback after annealing should be minimal.
5) If you can get it, run a mandrel through the case at the end, about .003" less than the desired bullet diameter.
The annealing stage of this sequence would mean that the latter stages of collet/bushing sizing are minimally affected by springback, as would be the mandrel. There are threads about several shooters who now anneal after ever shooting.
The mandrel and annealing should result in a very consistent neck tension and no donut effect.
I don't know -- for the casual reader, please don't assume that my idea above is gospel. Never tested. Just throwing it out for comments.....