This is a new one for me. I discovered a small crack, about 1/8" long, longitudinal on case neck and shoulder. That is, it is on both neck and shoulder. WW 25-06 case.

Brice- Not really so strange. This is an area that gets work hardened every sizing.

Not strange; it happens.

I have found cracks in new brass straight from the bag

Sounds like a work hardened crack due to a too thick neck or working in the resizing die.

If it were a .30-06 necked down to .25-06 then it is not uncommon for wrinkles to form in the shoulder (typically from excess lubricant). Those wrinkles may eventually become cracks after a few firings. However, if the brass came from the factory as .25-06 then it would usually have to be subjected to several excessive full-length sizings to cause a work-hardening crack in the shoulder.

Thanks guys. Not new, just new to me.

Once I started annealing the neck and shoulder area every 4th or 5th load I never saw another... Some of those cases in 300 WM have about 16 reloads now.

I had some on once fired RP in 375 H&H. Annealed them too and I'll see if I get any more.