Used my 500 for some skeet occasionally in early 90's and then I noticed a round gouge in the chamber and took it in for repairs. The gunsmith said it was caused by a screw (in the bolt action I guess). The last time I fired the gun was mid 90's at the range firing slugs, everything was ok. Now just rack it when cleaning occasionally. Found a broken pin from the gun on the floor and noticed a long teardrop shaped gouge in chamber. I can see the pin sheared off or maybe had a hairline crack that finally gave way and it split in two. It's easy to see it came from the side of the bolt. Gunsmith said if it broke out all the way the bolt could shoot out the back of the gun. Correct or not I dont know but I think the pin is called a "bolt lock pin". This gun seems like a lemon especially for the little use it has had. Does anyone have an idea what could cause these problems. All the smith is going to do is replace the pin but there must be something causing these problems. I dont trust the gun anymore.