Not all Ithaca pump stuck shell issues can be cured by chamber polishing. Les Hovencamp, former head smith at old Ithaca, re-cuts or enlarges the barrel notches wherein the extractor/ejector hooks engage the round's rim. This made the difference on an old 20 gauge I had issues of extraction of steel headed ammo. In a new 870 Express, the chamber was noticeably rough and wouldn't handle Remington loads, but would properly digest Winchester. Go figure...Gil