Hi guys,
I tried to get a picture of this but the details is just too small for my phone camera.
I have some new brass, and brass which has been shot once or twice with well below max loads.
There seems to be a tiny ring that looks (to a novice) to be the start of case head separation.
It's ultra fine, on some you really have to examine it to see it.
Doesn't feel raised or weak, it's just a slightly different colour ring around it.
Even on the new brass...