akpls: "... since I've learned that the 7mm is the minimum caliber that can be used to hunt big game in Namibia. I had planned to use my .257 Roberts on springbok and smaller on my next trip, but it looks like that is out."

I am not sure about that 7mm minimum in Namibia. It may be just a request of the outfitter. My son and I went to Namibia this past August. We took a .264 and a .338. We took kudu, hartebeest, mountain zebra, black wildebeest, gemsbok, warthog and springbok with the .264 loaded with Barnes 140 grain XLC's. The combination was deadly.

I would not hesitate to take my .257 for smaller species.

Oh, and by the way, you can't go wrong with any of those 3 7mm calibers. I personally have a hard time deciding between the 7x57 and the .280. I like and use them both.

The 7x57 would be a good choice. Don't have to worry about bullet depth like on the 08 and is more efficient than the 280. Could shoot anything from coyotes to elk, possibly moose.

I vote for the 7mm SAUM from remington in a 700 Ti. This is a 280 Imp. w/ factory dies & brass ready to go in a light rifle that you didn't have to spend 3 grand to build. Almost a 7Mag w/ less recoil & in a handier size.