Do you see the dull band at 12/32 above base? That is sign of case stretching and imminent case separation.
I found exactly the same thing on my 223 brass, only it is slightly higher up. In LC NATO brass it's exactly halfway up the body. In every instance the "paper clip" feeler confirmed thinning at this point.
This is one of the major issues with 23deg shoulders, and why I designed the 22Tactical with a 30deg shoulder.

No signs yet with a pick or visually. I do check regularly because these long tapered cases are prone to it.