I haven't used the .270 as much as the 7x57, mostly with 150-160 grain bullets, which works pretty much like the .270. Am goingf again in May, with the same 7x57 and probably some different bullets in the 150 class. The PH I am going with is originally from Zimbabwe (born and raised there back when it was Rhodesia), but moved to RSA in 2000. He saw the 7x57 on my sheet and e-mailed me enthusiastically. It is the only cartridge he has used on plains game for many years, except for the odd .375 on eland, mostly with 150-grain bullets. He is now about 60 and has shot piles and piles of various animals with it. His is stocked by Purdey, I believe, where one of his sons works.
Anyway, a good .270 bullet in the right place will obviously do the job.
Make sure to get a picture of your PH's Purdey stocked rifle for your article about the 7x57 in Africa
