If Caribou are factored in as about the same as Mule Deer, Id have to say .243W is a MOST EXCELLENT round to get 'er done out to 300 yards.
The range restriction is sorta self imposed, but some fellas do well way beyond that.
Here in the Arctic its consitterd an all around cartridge.Muskox, Caribou, Wolves, Moose, Black Bears and in a pinch, a Brown or Polar with little difficulty.
The .243W's (and the .22-250) are the favorites of Seal hunters, because its extreamly hard to judge range on ice, and its flat shooing qualitys are a big help there.
My wife has a Ruger M77 with a fixed 6 Luopold, and its been doing the job for 15 years now.
Formerly I used a Remington M700 ADL with the stock shaped to my use, sans cheek and comb, with a shortend pull and a slimmed front end. On the open sites, I removed the front bead and made it a blade, and then leved the rear site into a straight across plain with a notch....
Open sites and a carry all day weight, I plyed my trade on hundreds of Caribou, a few Moose, a dozen or more Black Bears and some Muskox ,in the 5-6 years I had it.
I used Remington 100 grain Coreloks, exclusivly, and the performance was Awsome!
I still miss that rifle.....