gkdir,
I have been a Weatherby shooter for over 40 years, all Weatherby calibers, except for the .224 and the .416 and I seen this fine shaving many times. I don't think you have anything to worry about at all. On my Weatherbys that is caused by the extractor sliding over the rim of the case head, or in the case of very hot loads or old factory loads that were loaded to 71,000 psi the base of the case would flow into the plunger recess (ejector) in the bolt face. In the case of the latter you would know, by sticky bolt lift and the brass disk that would be shaved off the case head everytime you opened the bolt after each shot.
In your case, I think you might a very small edge or rough spot on the extractor.
Good shooting,
Marcus.
