They may be adequate for the animals that you may be hunting and then again the guide service that you are going to use may not allow them. The best thing to do is to contact the guide service that you plan on using and ask them about it.
I know that here in North America there are guides for moose and bear in Alaska that require a minimum of a .30 caliber and up.
They would be adequate for the smaller of the plains game, but if you're planning on getting into the kudu and eland size animals, you will want to move up to at least a good 30 caliber or better rifle with a good bonded bullet. As critter mentioned, when you pick out a PH to go with, it would be a good idea to get their recommendation to make sure when you get there that they don't say your rifle is too light for the task and make you use an unfamiliar one of theirs,
I had the idea of calling antelope, never had heard one before and this was my first antelope hunt and archery one to boot. I know it sounds crazy to most hunters calling a antelope but I just had it in my head that I was going in the middle of the rut and they have to have some kind of vocalization at this time of year. Mention antelope hunting and calling in the same breath, well the old timers thought I fell off the rocker and the bets were on!The knowledge about antelope hunting and...