I had a serious cyclider jam with my SW Model 19 and .357 Magnum rounds. It jammed, would not turn nor could I open it. Keeping the barrel downrange, I messed around with it for a while, then, while grasping the gun by the cylinder, had a really nifty hangfire, which injected fire, brass, lead and powder right into my hand.
Yup, that was fun, but at least I got a good story out of it.
***I had a serious cyclider jam with my SW Model 19 and .357 Magnum rounds. It jammed, would not turn nor could I open it.***
It sounds as if you had some unburned powder grains behind the extractor.