Thread: Interesting...

Case head expansion is exactly that and it is measured at the largest part of the taper prior to the extractor recess. Its evidence varies depending on the quality of brass and loads and is more prolific in my experience in long action cases. I get some in necked down lapua 30-06 brass with a medium load and then it settles after the first firing. If you get it in short action cases (.0003-.0005) there is something wrong alright, unless it also settles.
Half cresent marks are the ejector rubbing on the head of stretched brass as the bolt is actioned through primary extraction. ( Rems and Tikkas have pretty good ejector springs and sharp ejector pins as well. So it doesnt take much to get the marks) It is interesting that damp hands can cause such a difference.