Like others have posted, its hard to beat a .30-06.
I bought my first centerfire rifle when I still lived in Colorado back in 1967, and it was a .30-06. For about 10 years I didn't have any problem keeping my freezer full of deer, elk, and antelope meat. Back then I loaded it with 150 gr Hornady Spire point bullets for deer and antelope and 180 gr Sierra GameKing bullets for elk, but with the concurrent seasons, either bullet worked fine for deer or elk.
In 1978 I had my .30-06 rechambered to .30 Gibbs, just because I thought the Gibbs case looked really cool. My .30 Gibbs upped the .30-06 velocities a couple of hundred fps, and for the next 20 or so years 180 gr Nosler Partition bullets from it kept my freezers full of elk, moose, caribou, and Mountain goat meat.
I currently have 3 Weatherby Vanguards, a .300 Wby, a .308 Win, and a .223. All shoot moa with my handloads, and if I was considering a new .30-06, I would probably get it in a Vanguard.
The question was asked "How's the 257 perform on elk?" I've mever shot a .257 Wby, but since 1978 my deer and antleope rifle has been my .257 Ackley. It would not be my first choice for an elk hunt, but one year a 117 gr Sierra GameKing bullet from it literally dropped my second best 6x6 bull elk in his tracks. I also had another friend that shot several elk with his .25-06. A .25 caliber bullet put in the right spot will certainly kill a bull elk.
