I've noticed that on my 300 WM the Remington cases seem to stretch more around the belt than the winchester cases. I see more stretch marks and what appear to be crackling looking marks. I don't know if you've seen this yourself on your cases but I'm thinking they are not as thick at the belt as Winchester's. Just what I've noticed so far. This seems to happen as early as 2nd or 3rd firing. I haven't tried to check the inside of the case I've just been throwing them out.