270WSM for plains game?

I have been considering the purchase of a Sako Finnlight chambered in 270 WSM for hunting the mountains of NZ with the view that I would also take this rifle to Africa, but reading the related threads here many suggest that the smaller calibres are unsuitable for the larger species of plains game.
Also in my arsenal are custom rifles that may be more suitable: a Model 70 in 338-06, a remington 700 in 7-08, and a Ruger No.1 in 9.3X64 brenneke.
The first 2 rifles mentioned are unsuitable for climbing around NZ as they are heavy, long barreled rigs (26" & 24" respectively, and around 10lbs). They have been built like this for culling at various ranges, thin whippy barrels are unsuitable for lots of repeat shots in the high temps we have here, I'm sure you'd agree?!
My Ruger No.1 & 338-06 would seem suitable, but my concern would be the availability of ammunition should my handloads not make it to Africa with me.
Your thoughts on my deliberations are welcomed please

Bushmantim,
The 270 WSM will be sufficient for all our plains game in Africa. In fact all the rifles you mentioned will do just fine. Most important thing is shot placement though. The 270 is a very popular choice to local hunter in South Africa and will take down anything on a plains game package. With regards to the other rifles, I dont think you really have to worry about the weights , since we dont really do a lot of walking in the spot and stalk methods.I would recommend premium bullets for your trip and time well spent on the rifle range. Hope I have answered your questions.

Kind Regards
Marius Goosen

Thanks for your reply Marius.
When you mention premium bullets, do you have any brands and styles in mind? I tend to use Woodleigh bullets here, but I'm obviously open to advice

The Woodleighs are highly rated here in South Africa and will get job done on plains game. Any of the premium brands like your Woodleighs, Barnes, Nosler's will work.
See you around,
Cheers