Anywhere the British Empire went during the late Victorian era this rifle followed. That being said, this wasn't just a military weapon, both soldiers and hunters used this weapon across the empire to hunt a plethora of wild game. From red deer and kudu to lions and tigers. It's capable of taking out game the size of cape buffalo and bison as well. I think that the addition of this rifle to the game would add a new historical weapon that was used to hunt wild game all across the planet.
Personally I would love to see it be able to take out classes 4-9 but I also understand that it fires a rather beefy cartridge with a substantial round. I know that the Martini Henry has been used (even today) to take out animals as small as roe deer and springbok. But that being said I'd be happy to see it enter the game being able to take out classes 6-9 as I feel that something the size of red deer and up is the bread and butter of this amazing weapon.