Wow what a subject I picked it up a bit late, saw there were a couple of jabs and over hand rights flying around earlier sorry I missed that, for the most part I will try to give a broad overview of what would be best.
Having grown up hunting Kudu as they were more plentifull than Impala I wacked a couple myself until I strted full time hunting 13 years ago, For some reason I think the question has been possed wrong it should be which caliber would be best suited for Kudu it what kind of terrain.
Kudu as we all know like varying landscape, in the Northern part of the Limpopo province on the border with Bots, they like the thck black thorn and the immense sickel bush thickets that can cover thousands of acres as well as the thick Combretum apiculatum (red bush willow) in some parts. in these areas a nice heavy slow traveling bullet would be the best choice.
375 h&h, 35 Whelen being my top pick, as well as 338 with a heavy bullet, 45-70, 3006 308 303 and even 30 30 I would however opt for at least a 180gr plus in the 3006, 180 in the 308 and 170 in 303, the slower and heavier the round the less deflection it will have but even the 375 or 45 7- with a heavy bullet still deflects it just deflects slightly less over distance. (Keep in mind defelction increases over distance, in my opinion shots through a little bit of obstruction should only be taken if the quarry it up against such twigs(25 -30 yards behind it is to far.....deflection increases and you stand the chance of hitting your quarry in a less than desiarable area of the body) But the slow traveling heavy rounds will give you a more true flight should you hit any little sticks or twigs. I need to add that taking a shot and thinking you will be busting through brush is a novel and foolish idea.
When you get into mountaineous terrain which kudu also love you are most likely to be confronted with a 150 - 300 yeard shot, here all the flat shooting 30's and there bigger buddies come into action, (once again I have shot 300 + with my 375 but let's be honest that is not its application)
Here your 7mm 300 super duper ultra short ported mag is perfect it holds velocity down range and has a reasonably flat trajectory (keeping in m ind that a trajectory can never be flat on this planet as gravity works on it the moment it leaves your barrel, it just keeps on falling for longer....;-) I have also shot many Kudu with my 22-250 but lets be honest it's not ideal, I would reccomend a 30 to any hunter that askes me this question the rest can be sorted with bullet weight, granted that it has satisfying accuracy.
I take my 375 anywhere but I know the rate of bullet drop and that works for me it is always good to know trajectories, on the other hand one could always invest in a 375 h&h stick a 270gr bullet in its throat and you have a plains game gun as well as a dangerous game rifle perfect for hunting africa, as a trophy hunter.
You know what screw that just buy a 375
My best always
PS I am slightly biast when it comes to the larger calibers....did you notice! ;-)