If you're hunting in the African bush (not the scenario described, I know) I'd want to carry the largest possible caliber. These animals are big and fast - you get one shot if you are lucky.
There are also other animals that share an environment with the hippo that are very well-armoured and hard to kill with one shot, like elephants, Cape buffalo, etc.
There are also other animals that share an environment with the hippo that are very well-armoured and hard to kill with one shot, like elephants, Cape buffalo, etc.