Dogger: A while back I killed a nifty 5x5 Bull Elk here in SW Montana with the 140 grain Nosler Partitions from my 280 Remington Rifle.
One shot through the heart/lungs and six seconds later that Elk was down and still.
I am not bragging but I am sure that Bull was 400 yards away - at least. No time for digging out the "range-finder" on that sub-zero morning.
Good luck on your Elk Hunt.
Come to think of it my customized pre-64 Winchester Model 70 in 280 Remington (25" barrel) has a Browns Precision stock on it.
Enjoy the Hunt with your son.
Hold into the wind
VarmintGuy