Doing a very good clean and lube on an "unknown" pistol is always mandatory. Look at the extractor in the breechblock. It is very easy for "crud" to form in the extractor groove, and not let it function correctly. Also, the extractor tips may be broken so that it is hit and miss on extraction. Also, the extractor spring may be worn out and has lost enough tension to keep the extractor to function properly.
There are many other things, but this is where I would start.
|