Darick: I own both calibers you are considering.
I have not killed an Elk yet with my 338 Federal so won't comment on it.
I have though killed a nifty 5x5 Bull Elk with my custom 280 Remington. I was Hunting Mule Deer at the time but an Elk opportunity came up and I mortified that Bull with a Nosler 140 grain Partition.
IF... I were specifically Hunting Bull Elk with the 280 Remington I would definitely use 160 grain Nosler Partitions in peppy loads!
I have killed other Bull Elk with the 7m/m Remington Magnum and these 160 grain Nosler Partitions.
Best of luck to you on your Montana Hunt.
Hold into the wind
VarmintGuy
