Minimum Elk Caliber. what do you think it is.

[6mm Remington]

6mm Remington one shot 30 yards with 100 gr. Partition. Entered right shoulder and exited just in front of the left shoulder on the other side. Staggered a few feet and I shot him one more time and he went down. He was dead on his feet but didn't know it.

6mm Remington one shot at 350 yards with a 90 gr. Nosler E-tip. Entered tight behind the rightr shoulder and exited the center of the left shoulder. She staggered 20 yards and went down.

 

[Frequently Banned Troll]

25-06 100gr Barnes TSX right down the gullet and he didn’t go anywhere.

 

[Frequently Banned Troll]

These would work just fine if needed, proper bullet placement requires as with all bullets. Both 62 grains going roughly 3kfps from muzzle. This would be my minimum

 

[mtmuley]

 

[Berger230Otm]

Always, the answer seems to be the annoying "It depends on"
Is your elk a bull or a cow?
What angle are you shooting at?
What's the range?
For me 27 - 33 caliber
if my rifle shoots them well and I can get in close I prefer light to medium weight monolithics. If monolithics won't shoot i try mid-weight bonded. Last option if nothing else works, heavy for caliber cup and core.
My go to load is Barnes 150 ttsx in my 300 Win Mag chrono'd at 3075 fps (I know it's slow but it's about the best accuracy I get and it tames the recoil quite a bit) For the data curious: @7,000' altitude, 20 degree temperature and 50 % humidity that bullet is still above 2000 fps.

 

[Berger230Otm]

For the minimum I'd go with a 270 and 130 grain monolithic if I was just told here's an Elk tag and I didn't know anything about the hunt.