Re: Hello from Indiana !
Howdy eeshup and good morning to you also.
I think you are on the right track with the .25 WSSM and could probably cut .050 off the neck, size it up to .357 or whatever you wished (within reason) and still have enough tension to control the bullet (with a properly placed cannelure and roll crimp, of course). This would be a short neck but as with the .300 Win Mag it might work fine. You would not lose much, if any, case capacity and no special dies would have to be made. You'd have to full size the case without touching the neck as a separate operation but this might work out better overall. It would get tricky if the neck isn't long enough.
I know your bullet selection in semi-wadcutters would be very good but you might consider .30 caliber in a light weight as an alternative also. I like the fact that a wide variety of long guns are available for this wildcat with a rebarreling the only real drawback.
The .408CT/.505Gibbs presents a different set of problems because you would basically be cutting the case in half and the wall thickness would have to be turned down before neck and shoulder forming could take place and you would have to anneal the neck/shoulder if you wanted a safe and reusable case. Because of the increased wall thickness below the shoulder the powder capacity might be less than your .357 eeshup wildcat but it would definitely take high pressure. The biggest drawback I see with using the .408CT/.505Gibbs case is the size of the large bolt face and the gunsmith charges inherent in making it a short action plus the rebarreling. There would also be a high cost for cartridges and custom dies. Not to rain on your parade but I would go with the .357 eeshup for reasons of economy and performance. I think it might be just the ticket for putting meat in the freezer and a great idea on your part. If you want more info on what you can do with a radical reforming of the .408CT/.505Gibbs I would try to get ahold of JD Jones and ask him what he thinks because he has the experience of creating off the wall cases (like necking the 20mm to .50 caliber and building a 95 pound rifle to use it!).
You are very close to me where you live. Are there any long distance ranges in your area or do you have to hope that wind-reading is not as hard to do as everyone says it is. My local range has 25yard to 200yard courses and strict rules and short usage times. They are open from 7AM to 4PM my time or dawn to dusk (whichever is shorter) because they use Eastern Standard Time and I am in the Central Standard Time zone. 4PM doesn't make much sense this time of year when there is another five hours of usable light to shoot with. I know, waaah.
Thanks for letting me in on a solution to the rifle taking deer in Indiana problem. I hadn't even considered this at all. I have two brother-in-laws who are going to get really excited when I tell them what you've come up with.
Thanks, eeshup, I'll see you later.