I went to the 38/55 because recoil was becoming an issue with both my Marlin and Rolling block in the 45/70. Highly recommetnd the 38/55. There are factory and handloads that take this into another realm for hunting if you think you need it. Orginal Factory spec ammo works fine for deer hunting.
Very pleased with my SS Rossi 92 in 45 Colt They can be made to work at a lower cost than reinventing the wheel on your Winnie. Will also handle magnum 45 handloads if you want a hunting brush gun.
Try neck sizing only cases that have been fired in that rifle. Use brass that was loaded up to the higher pressure levels in hopes that they have expanded enough to seal.