Geez - I thought the only rifle that had this "issue" was the old Remington 742 Auto BushMaster - otherwise affectionately know as the "JAMMASTER"!
As for that rifle itself, there really wasn't much of a "fix" for the issue, even though Remington admitted it was a BIG problem. They actually offered a trade-in for the 742, for their reworked 7400 - although the offer was quite one-sided - in their favor of course. :sleep:
I had a gunsmith tell me he took a drill with some kind of sanding cylinder and honed out the bullet seat, as this area was swelling due to a heat issue and causing the casing to stick, which basically yanked off a small corner of the brass casing with the ejector.
For me, I used a set of dental picks (picked up from a local dentist office, which they throw away on occasion) to get out the casing in my old 742. After realizing this issue was NOT going to go away, I promptly sold it.