Ooooooo! I just stumbled on this old thread.
I acquired a sort-of family heirloom old Marlin that is marked for 25-20, but was rechambered for, I believe, .255 Dean at some point in the last 110+ years since it was made. It also got wood from a newer 1894 at some point as well. Just yesterday I ordered some fancy dies and parts and bullets and I'm hoping I can make it work with the right ammo...
It fires 25-20 just fine, but it fireforms the cases and blows the shoulder way forward, so I'm hoping that with a neck size only die, and a modified seater, I can reload the formed cases. If I have to, I'll order a Vickerman inline seating die set up for 25 caliber. It'll be a fun project.
(attempts to add photos said that 400kb is max size...I'll have to reduce quality to crayon drawings and try again after work)