I purchased some once fired 357 brass. Typically I only purchase new brass or use the once fired brass that comes from my ammo purchases.

I had some down time today so I decided to reload some of the once fired brass that I had purchased. I noticed what appears to be, for lack of a better term, a "ring" around the primer pocket. I resized the casesand cleaned primer pockets.

I noticed that when seating the primer it was unusually hard and noticed metal shavings fall out around the primer pocket. Out of 50 I had one that would not accept a primer, almost like the primer pocket was not centered. The installed primer on the cases with the "ring" are flatter than normal. I assume this is from the extra pressure required to seat the primer.

I did not like the looks of the primers of the 50 I had done so I retrieved some of my personal once fired cases. I resized them cleaned the primer pocket and the primer set with normal pressure and looked correct.

I was worried that the primer would blow out if I loaded them up. I don't know if this is correct way to check but I put the cartridges, primer only no bullet or powder, into an old Taurus that I have. They all functioned but the primers on the cases with the ring blew out of the pocket and were deformed. It took a little work to get the Taurus open but no damage to the pistol. The cases that I primed without the "ring" looked worked fine.

Can anyone provide any information what the "ring" around the primer pocket may be from. Also has anyone had this problem?

Top row is my once fired cases without the "ring"
Next two rows were purchsed as once fired and have a "ring"
From left to right before priming, after priming and after firing.