For general hunting 100-300 yard shots with confidence that you could make a clean kill in most shot opportunities.
I have used a .308 Winchester, .30-06 and .338 Win mag to do the described tasks. A .308 or .270 Winchester with 150's would make fine minimums.
Though I don't shoot one, I have three hunting buddies who have used .270 Winchesters to take many elk.
