That mark on that case may be where your sizing die stops. If so, your case displays evidence of possible case head expansion.

Case head expansion has two possible causes: brass too soft or loads too hot.

I'd suggest miking a new, unfired case just ahead of the rim and recording the reading. Do so again after firing. If the case head area expands more than about 0.0005 inches ( 5 ten thousandths of an inch), you're in troubled waters. I'd try a different brand of brass and/or reconsider my loading data.