Nathanial,
Assuming those 255gr factory loads are jacketed bullets, you really can't make any judgements on what size cast bullets will shoot good in your gun. You can successfully shoot a much smaller jacketed bullet than you can a cast bullet, especially a hard cast bullet. For example my 38-55 has a groove diameter of around .3805 and it still shoots .375 jacketed bullets fine, but takes at least a .380 cast bullet to shoot well. You really need to slug your barrel to know what you need unless you just figure it out by trial and error. From what I have read, I would guess a M94 of that era would be close to .379 groove and the .376 Hunters may not work very well. I shoot .381 Hunters in my 38-55 and they shoot great. .381 is pretty large and may not chamber in all 38-55's but the .379's probably will. The Hunter bullet is a gas check design sold without a gas check. I put gas checks on them. I would keep them at 1600 and under without the gas check.
From my personal experience, a high velocity .24 or .25 expanding jacketed bullet will cause a lot more tissue damage than a hard cast .38-55, but the 38-55 will work and will really penetrate. One thing I really like about switching a gun to cast is once you get the size/velocity/alloy combination figured out you won't get any lead fouling and of course copper fouling is a thing of the past making gun cleaning very easy. Good Luck!
Assuming those 255gr factory loads are jacketed bullets, you really can't make any judgements on what size cast bullets will shoot good in your gun. You can successfully shoot a much smaller jacketed bullet than you can a cast bullet, especially a hard cast bullet. For example my 38-55 has a groove diameter of around .3805 and it still shoots .375 jacketed bullets fine, but takes at least a .380 cast bullet to shoot well. You really need to slug your barrel to know what you need unless you just figure it out by trial and error. From what I have read, I would guess a M94 of that era would be close to .379 groove and the .376 Hunters may not work very well. I shoot .381 Hunters in my 38-55 and they shoot great. .381 is pretty large and may not chamber in all 38-55's but the .379's probably will. The Hunter bullet is a gas check design sold without a gas check. I put gas checks on them. I would keep them at 1600 and under without the gas check.
From my personal experience, a high velocity .24 or .25 expanding jacketed bullet will cause a lot more tissue damage than a hard cast .38-55, but the 38-55 will work and will really penetrate. One thing I really like about switching a gun to cast is once you get the size/velocity/alloy combination figured out you won't get any lead fouling and of course copper fouling is a thing of the past making gun cleaning very easy. Good Luck!
