I have a couple old .22's. Marlin pump model 20 and 29. Also a Stevens Favorite. On pretty much all of them, when fired now adays the spent case swells and gets stuck in the chamber. So much so the extractor will not grab it. It's not a extractor issue. Seems like the chamber inside diameter has increased ever so slightly. Why has this happened? or what has made this occur? A real bummer as these are functionally fine little rifles and would be fun shooters. Thanks all.