Can anyone tell what might have caused the large black ring on the bolt face shown in the picture on this GB listing. The seller says it's new and he hasn't a clue what it is. You will note that the circle is much larger than the carbon rings that are primer pocket sized. I am considering bidding on this listing so as to have a spare part on hand for my PPC.
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=233452320
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=233452320