To many post to respond to.
NitroX, Thanks for the welcome back. It has been a long time. Yes i still do silly things like that.
I recently hunted giraffe in Limpopo province with a friend. We were out to shoot Hippo and buffalo as well. we shot the buffalo cow with a .458win mag loaded with 300gr LWHV Impala Bullets. Text book results. Shot her from about 20meters and everything went well. Old cow who caused some problems under the farm labourers and the other animal. Aggresive bitch. Had some flashbacks of my mother in law. Not part of the issue here but keep the bullet in mind.
Day before we were hunting 3 giraffe bulls of which I was fortunate to shoot 2.
My buddy (who shot the buff) shot the first giraffe with his 270win loaded with 110gr Impala LWHV bullets. This was after he nearly had to persuade the landowner with the very same gun. Good shot between the eyes from about 70 meters. Dropped in its tracks. Big bull with nice skin. I was up next and when the land owner asked about my rifle he nearly collapsed. I took a fair sized bull from about 100meter cleanly behind the head. The second bull was from about 140meters facing me and so did he fell to a shot between the eyes. All done with a .243win loaded with 65gr LWHV Impala bullets. NitroX, I told you I was still doing silly stuff.
I have taken basically every huntable animal in South Africa with that very same .243 win exept bigfive. I have shot kudu, wildebeest black and blue, warthog, bushpig,eland, giraffe and many more smaller ones with it. Now the question arise again? Is it to little gun for these animals? Please do keep in mind that I do a lot of culling and commercial hunting for butcheries etc and that all shots taken must be high up the neck or in the head otherwise the clients do not accept the meat. I firmly believe that with a well placed head shot and that small bullet travveling close to 4000fps I can shoot any animal on this continent.
Lastly, please keep in mind that I do not advocate this kind of practice and I would think that it would be very very irrisponsible for somebody to try who is unexperienced. I do this for money and I do it a lot. But at the end of the day the a very small caliber did all the jobs cleanly.

PS! The land owner afterwards told me that he totally changed his perspective of smaller calibers after the stunt myself and my friend pulled off. I even told him not to try it unless he is 500% sure he knows where his bullets are flying.