Do you really mean it won't extract the shells? Does it pull the shell out of the chamber? Does it do it when you work live ammo through the action or just when the shell has been fired? If the fired shell sticks in the chamber- - does the extractor rip a bit of brass off the shell? If it does then you have to wire brush the heck out of the chamber. If the shell stays in the chamber but comes out easy with you fingernail or knife blade then its the extractor. Either broken extractor or broken extractor spring or it is just stuck. If the extractor pulls the shell out of the chamber but does not throw it out then it is your ejector. Exploded views are available on the net for this common gun.
Just walking on the edge of of my grave.