You need to get some solvent in there
I would recomend laquer thinner,when you go to the home store to pick it up get the largest steel rod that will fit down your bore (1/4"=.25 to big,3/16 ok) or be willing to sacrifice a GI or other STEEL rod. If going the 3/16 rod route you can wrap scotch or electrical tape around it to protect bore.Just make sure whatever you slide down the bore is clean and has a nice square end. (no threads or such)
Take your upper outside (laquer thinner is mucho flamible and stinky )and pour some down it,cover and soak,repeat.You should stand the upper pointed up and pour a couple spoonfulls dowm the bore so the case overflows and seeps down between the chamber and the case. Laquer thinner will evaperate fairly quick so you need to cover and repeat. Let the solvent work on the laquer/polermer/dirt or whatever is glueing the case and don't be afraid to really rap the rod.WD40 or KROIL (the oil that creeps)might work also
A steel rod works best, a cleaning rod with male or female thread will only mushroom and then you will have a case AND a rod stuck in your gun.
If the solvent doesn't work after a couple tries (give it several hours to soak) I would try the KROIL or wd40 and let it sit for several days
I once had a jacketed bullet stuck in a 26/06 several inches ahead of the chamber. Two gunsmiths gave up on it after I mashed the spire point and jammed it tight.Ilpounded like hell on it and it wouldn't budge. I let it sit for a couple of days with KROIL oil and it slid out with a couple of medium taps.Amazeing stuff. Soak lead crusted pistol barrels with it and the oil will work behind the lead and it brushes right out !!