My M-85 AK pistol will not extract. I end up with a round jammed under the rim of the unextracted case every time. Installed new extractor and spring to no avail. I'm sure the thing is way overgassed. I'm thinking it is a timing issue. Extractor is trying to pull out an expanded case and it's sticking in the chamber. I'm thinking I need to polish the chamber and see if that helps. Any suggestions would be appreciated.