Are we talking about the extractor or the ejector? The extractor is part of the bolt assembly while the ejector is in the receiver wall on the left side opposite the port. Following your description, it seems as if the cases are not being pulled from the chamber, which suggests an extractor problem. Possibly someone filed the hook on the extractor and it doesn't engage the cartridge rim sufficiently. I'd see about replacing the extractor with a new one.
