Thread: 7mm Rem Mag sizing problems

If they chamber ok I wouldn't worry either. That bit can be tight to size, but You do often get a line there after more firings though which is the case thinning, keep an eye on that with a paper clip to feel for it or cut a case open from the batch.(but you will see it on the outside clearly)
I've had some guys say the thinning is a headspace issue. But maybe it's more a loose chamber/tight die situation, as my headspace sizing is much the same as a fired round.