I'd use 300-325 grain hard cast bullets and nothing else. As to what range you can take one with it only YOU can answer that question. How far can you put EVERY bullet into the kill zone under the stress and excitement of the hunt and perhaps out of breath from the stalk? That is the answer to your question and only you can arrive at it.
The gun is fully capable at 100 yards or more IF the bullet is placed where it needs to be. With iron sights I currently place my own personal limit at about 50 yards for deer, maybe 75 if everything was really perfect and I felt really solid for the shot. On elk I'd likely go to 100 if I really had to but would prefer to stay within about 75 yards.
Scoped you really only aid in the precision of shot placement but the wobbles may offset this. From a rock solid rest sure it's easier to place those bullets but under the stress and excitement of the hunt? Dunno about that. I don't use scopes on revolvers anymore. IF I want to scope it I use a TC.
GB