I had not shot my 6mm-250 for awhile so I pulled two partial boxes of ammo that I had loaded 10/14 and another box loaded on 3/15. Looking them over, I noticed that all the necks of the loaded rounds had a crack. When I held the bullet in one hand and the case in the other, and applied a slight side pressure, the brass fractured along multiple lines, not only along the original crack. The necks appears to have lost all malleability. The 10/14 box is 2x fired R-P .22-250 brass with Berger bullets. The 3/15 box is 1x fired WW 22-250 brass with TSX bullets. The two boxes of ammo only had RL-17 and CCI 200 primers in common. I've checked other stored ammo loaded around the same time frame with CCI primers but with a different powder. Those appear normal.
I've taken several empty brass cases from each 6mm-250 box, resized them and seated a bullet. The cases behaved normally.
The above observations seem consistent with a WAG that RL-17 out-gases something that makes brass under bullet tension brittle over time.
Wondering if what happened is an isolated case or has happened to any others.
