8x57 is a great elk caliber. It has a quite a bit more reach and a lot more knock-down power than the 30-40, and is not a powder hog like some calibers I could mention. Plus you can put a scope on a Mauser. I use the Krag 'cause I like it, and I like the history it calls up. And it will put an elk down if you do your part.
jn