Match the caliber with the game. 30'06 with 180gr+ is sufficient. Sure, a perfect shot placement with a 22-250 will take an Elk. Shoot one through the heart and don't hit a rib bone, a 22-250 will take an Elk. But it isn't ethical to use inadequate gear to take an animal. Don't use anything smaller than 30 caliber 180gr at 2800+ fps on Elk. Yes, 7mm using 175gr would be OK also. Using a 257/270 on Elk is just dumb.
