I had that happen once.
I ended up welding a rod onto a drill, drilling the case, tapping it to 1/4NC, screwed a threaded rod into the case and pulled the case out. I used some brass fitting in the rear of the action with a nut and washer to pull against. It popped right out then. I guess you could use a small slide hammer also or make one by using a weight with hole in it over the threaded rod.
I had taken it to a gunsmith buddy and he tried to get the barrel off but it was pretty tight. I just told him I 'd take care of it and was done pretty quickly, 20 minutes or so welding included.
Oh, I remember what I pulled against! I used a piece of plastic pipe like cpvc. It fit over the case and through the action and pulled with a washer and nut over the end.