I have shot mine at targets out to 300 yards with suprising accuracy. On game a hot load in a SRH will easily take a whitetail put to 200 yards.
The problem becomed getting the bullet drop correct.
I would personally hold shots on big game to 150 yards and under with a scoped 44 mag SRH.
I would also recommend you use a heavier bullet for longer range shooting. Also I would recommend a quality LBT designed hard cast. At longer range you will not get much expansion with a HP or SP bullet and the wide nose on the LBT bullet designes are better on game anyway in my opinon.
Its all putting the bullet on the right spot with handguns and then getting penetration. With the heavy hard cast, the latter is never an issue.
Kirby Allen(50)