It just does not matter that much.
I'm not going to lose any sleep over it. If circumstances left me with only my 30-40 Krag,I'd get by. It has a bolt peep. Its a great cartridge for cast bullets.
I'm not scared of 200 yds.
6.5 Creedmoor? 6.5x55 ? in a 98 Mauser strength rifle, its a shade of grey. Same with 7x57. 308 ? 30-06? 8x57? Shades of grey.
270 or 280? Both great.
I made my 257 AI to suit me. I've done most of my hunting with it. It carries easy. I shoot it at least as well as I shoot anything. I've never carried it elk hunting. I have better suited elk rifles. But if it was my only rifle elk season,I'd use it,no problem.
Which rifle/cartridge I carry I might change up for nothing more than fun.
I've missed a few pronghorn seasons lately. Killed enough of them,I guess.
But last time I took one,it was with the 1903A4 Springfield I counterfeited. 2.5 X Lyman Alaskan . 30-06....165 gr Ballistic Tip. Just over 200 yds. Boom,whop! Flop. I'd use it on anything.
In my PO Ackley book,there was a cartridge (By Warren Page?) called the "260 AAR" Its simply a 6.5 version of the 257 AI. If I ever rebarrel my .257,I think I'd choose that. With the bullet selection..that might be the one.
That would move it up a bit for elk use.
I've been in Colorado since 1966. It has its own terrain and weather,which influence hunting style.
Frankly,my boots and sox are at least as important as "Which rifle?" I hunt walking.