The case web is solid at that point just the flash hole so not separation. Do those cases chamber freely, if your fl resizing they should just drop in and the bolt close with no resistance. I assume you lube the cases. Can you measure the bulge with a micrometer? I sometimes get something that looks similar when resizing dirty brass, the lube and die polish the case where it is resized and it looks like their is a ridge at the bottom.
Bookmarks