I just purchased a used. 1989, mod 60. It was supposed to have been from an estate and unfired. I believe it was fired, but from the looks not much. Problem is that the bolt is tight and won't go closed all the way after firing a round. I tried some clp on the parts but even sliding by hand it doesn't feel smooth. Any advice on what to do. I put about 100 rds thru it so far, and about half needed the bolt assisted closed.