Case forming issues

[Crane]

I just fire formed some Ackley cases out of some factory loaded 25-06 rounds. After running them through Redding dies (three die set) to de-prime and the usual case prep several of the cases won't even hold a seated bullet. The cases are Winchester. I was gonna anneal then eventually, would this help? I loaded up 16, 2 each of the same load increasing by 0.2 grains for eight total loads to test.

I guess this is lack of neck tension from becoming brittle, I didn't expect this from one firing. Sound right or something worse.

 

[MagnumManiac]

I just fire formed some Ackley cases out of some factory loaded 25-06 rounds. After running them through Redding dies (three die set) to de-prime and the usual case prep several of the cases won't even hold a seated bullet. The cases are Winchester. I was gonna anneal then eventually, would this help? I loaded up 16, 2 each of the same load increasing by 0.2 grains for eight total loads to test.

I guess this is lack of neck tension from becoming brittle, I didn't expect this from one firing. Sound right or something worse.

I doubt the brass has gone brittle.

Have you tried removing the expander from the die and running your brass in without it?
Are you sure you're running them into the die far enough?
Are you using the FL die or Neck die?

If you have a fired case, measure the diameter of the neck and compare it to a sized case and a loaded case, this will soon tell you where the problem lies.
It may just be that you got a die with a loose neck dimension, but could also be the brass having too little in the neck walls.

If you give me the above info I've requested, I may be able to help sooner, instead of going through every possible cause.
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