Can you back the expander and pin up enough to drill and tap the case head? If so, do that and then put it in the freezer overnight and try to pull it out with a threaded bolt.Who makes a stuck case remover that will fit a 470 ne. RCBS to small to fit the tim.

You may be able to use about a 5/8" 12 point socket with your RCBS. May need a longer bolt.Who makes a stuck case remover that will fit a 470 ne. RCBS to small to fit the tim.
Exactly what I did without issuesDid you pull the rim off?
Is the expander still stuck in the case?
This happened to me and the only thing I could do was to unthread the stem and chuck the die in the lathe and drill out the base of the brass to get the expander out and then used a tap in the drilled hole and a brass rod to knock the brass out. Soaked it in penetrating oil overnight first.