RE: 7x57 for caribou, Bear, and Moose
7x57 worked for Bell and others because they knew enough to use the "proper" bullet for the intended job. It will still work today if you match the bullet to the game. For moose and bigger game i'd NOT use less than a 160 grain bullet.
I killed some big caribou with a 7x57 useing 175 grain Speer mag tips. They worked very well. I used the heavy bullet because there was Brown Bears around where i hunted.
Drilling Man