Rather than selling, I think you need to find yourself another elk hunt and employ this rifle as you'd intended. If you were so committed to an elk hunt that it merited its own custom rifle...

There's a lesson here for everyone, particularly to those who now can afford just one rifle: "Buy ENOUGH gun, but not TOO MUCH gun". The latter I see violated the most. All too often I've seen it advocated in gun rags and on these boards to purchase way more rifle than the intended quarry requires, as if anything below it were somehow "inferior".

My rules and categorizations are pretty simple:

Varmints/Pests: .22LR is ENOUGH, just about anything else will do

Varmints/Furbearers: .22 Hornet is ENOUGH, above .243 is TOO MUCH

Deer/Pronghorn: .243 is ENOUGH, above .30-06 is TOO MUCH

Elk/Moose: 7mm-08 is ENOUGH, above .338 is TOO MUCH

Obviously, there are some overlaps and underlaps. You want to hunt both deer and elk? Your minimum should be 7mm-08, but you don't need anything bigger than .30-06.

IMO - the .300 Magnums, and anything above .30-06 for that matter, are niche calibers, great for elk and moose but not much else that most of us will ever be able to afford to do (Alaskan bear hunt, African plains hunt, etc.). Unless you can afford a varmint rifle AND a deer rifle AND an elk rifle, one would be wise to steer away from them.