there was a time back in the 60s when Field and Stream and Outdoor Life touted the .257 Roberts as an Elk rifle.
It is one. I shot my first elk with it in 1984 using a Winchester XTR Featherweight...
Then a Pronghorn...
I used it for many other deer and elk over the years, but then graduated to a .30-06, .35 Whelen, and now think that the .30-06 Ackley Improved is just fine. 180gr Nosler Partitions or Ballistic Tips are bullets are my go-to.
When hunting elk, you never know if you're going to get a shot at 300 yards, or at 30 yards.
This bull was taken at 30 yds. and was basically point-shot from the hip as it ran by in the brush.
This Elk was 300+ yards and on a hillside...
This moose was only 70 yards away...
All were taken with one shot and using a .30 cal 180-grain bullet.
Now, I'm not saying nothing else will work. Not at all. My brother recently switched to the 6.5 PRC using a 147gr bullet. My stepdad went down to the 6.5 Creedmoor. My brother gets giggles from shooting .5 moa at 600 yards. My step-dad has a bad neck and shoulder and the 6.5 CM makes hunting tolerable. Both are still killing animals.
There are just so many variables in elk hunting that saying one caliber is the "best" shows a lack of experience. I have settled on a .30 cal bullet at 180grs going around 2700-2800 fps as the most versatile and effective. But that's me. I know that it kills things and is not too punishing to shoot. Others may find a smaller bullet going faster to be better. And it may be. I just tend to not get too excited in caliber discussions when it comes to hunting.
Some may say that shooting an elk at 269yds with a .257 Roberts with a 120gr Nosler Partition was foolish, but it worked. The man that gave me that rifle and loaded that ammo was my father, and I'm willing to bet that he has hunted more species of big game on more continents that anyone on this forum. He knew how accurate I was and that a well placed shot would drop an elk. It did. He then loaded up some 117gr bullets for the antelope hunt and those worked as well. I always trusted his recommendations for calibers and big game. He gave me my .30-06 Ackley Improved and said it is the only caliber I would need for hunting in Idaho. So far, so good.