I was thinking of going with a .300 win mag, but also considering a .300 RUM, as well as a 7mm rem mag. My main concerns are being able to shoot it accurately due to the recoil and that the bullet has enough energy to take down an elk at long range.
There are lots of good muzzle brakes out there, my 300AX drives a 200gr accubond 3340fps. It wears a Pain Killer brake and is second to my 243win in lightest recoiling rifle I have but boy is it loud!!! I would make it a point to get a good brake just for the sake of 1. Taming recoil and 2. Being able to spot your shot.