Thanks bpjack.  I have one more “easy trick” to try, but if that fails, I may have to dust off the old lathe (as well as my rusty lathe skills, and try to make one like that.  There is a little bit of a “tail” on the ring of brass that was left, so I’m hoping that Cerrosafe may come to my rescue.
I want a nice chamber for that Jameison brass dave is sending me!
Froggie
PS  It appears that you just made one slice through the end to expand on. Is this correct?

I don’t have that option with the 25-20 SS.  I have a couple of Rem UMC cases that are probably prewar, but I don’t think anyone but Jameison and Bertram (and of course BELL) have drawn any in the last half century or more.  The turned brass ones are also a possibility as are the ones made by (radically) altering .223/5.56, but those really don’t do much for me, especially since ssdave has kindly made the Jameison brass available.
Froggie

UPDATE: After nearly 5 months the stars finally aligned. I found my chunk of Cerrosafe and small ladle, and carried them, along with the poor, injured low wall up on the mountain to my friend Moodyholler.  I like to work in his shop because it’s almost as messy as mine and I feel right at home!
We cut a patch of scrap cotton to make a wad and pushed it in from the muzzle to the chamber’s throat.  I’d love to say it came out on the first try, but I got sloppy and pushed the wad in too deep.  I got a nice chamber cast, but the C-S didn’t go in far enough to hook the case mouth.  On the second try I put the wad about 1/2” in front of the case mouth, and now I have a C-S chamber cast with a brass ring.  I’ll polish the chamber a bit to make sure it didn’t get scratched during out various efforts at extraction, but it looks fine to the naked eye.  I bought 50 rounds of new 25-20 SS Jamison brass from ssdave so now I just need to cast up some bullets from one of the Ideal moulds I have (including a Perfection mould w/out a mould number… it’s just marked 25-20 in large numbers.)
The Frog is finally off his lily pad and back ready to shoot again!  You know the old saying, “If a frog had a gun he wouldn’t be scared of snakes!”  Look out snakes. 
Froggie
PS  I’m thinking hard about making a case extractor (à la bpjack) but I’m thinking the new cases from Dave will eliminate the problem and make that tool unnecessary.