Old Mossy Horns
Essentially it has then become a .30-30?
I dont like 125's for Deer in a 357. I use Rem 158 soft nose. These work the best for 2 out of my Contender and Model 27 but I also have some 180 XTP loads from Top Notch Ammo that were deadly.
For those with 357 Mag Contender barrels, they are known to have long chambers in them. Try a Max case in them they may just fit!
Even if they won't fit a full Max case, it will probably be somewhere between Mag and Max, if you are a handloader you could cut Max cases to fit the long chamber and work up a load for it. Call it a
357 Mag Mag or 357 Mini Max! LOL
I killed it. Soaked it in water awhile and then gun oil before putting it in the case.