I have a High Standard derringer in .22 Mag and it works fine but the rifled portion of the barrel is so shallow and short that the bullets keyhole at anything beyond a couple of feet. Not a whole lot better than a knife.
It sounds like your chambers need to be polished - can’t imagine the fired brass could stick that hard in the chambers unless they are loaded with tool marks.
The extractor would move them up but from there they were stuck. The problem seems to be related to the extractor ( I guess). I first tried to remove with a wooden rod which promptly broke. I then inserted an aluminum cleaning rod (with no tip on it) and pushed it against a wall with no luck. I did not want to be too rough with it and break something. Lastly I had luck with a pair of needle nose pliers.