I have seen different methods of forming 25/20WCF brass from 32/20, but many seem to take several steps. This method has worked great with very little loss of brass in the process. Start first with running the 32/20 brass through a Lyman "M" die to make sure the necks are perfectly round. Take a 25/20WCF seater die and remove the seater stem. Full length size the 32/20 case in this die( use Imperial sizing wax). Go to the 25/20 WCF
full length size die and remove the expander plug. Slowly work the case into the die. Next use a Lyman "M" die for 25cal. That is all that is involved, works great for me, and very little cases damaged in process. I have only used Starline brass in the forming process.