The OP said the shots would be 300 yards max. That's unrealistic in many elk hunting situations. I like the extra reach of a 300 magnum. My rifle is a 300 WBY. When I hunt with my 300, I've never said, "I wish I had a lesser caliber."
I killed a 370 score elk with a .300 Wby, 180 gr. Partition. And, you're right, I sure didn't feel overgunned...
That combo did the job without a problem.
I have a great .375 H&H that's not heavy and a great shooter. Just for grins, I'd consider working up a load and trying it on elk.
Why not... May try it on WT's and hogs next fall. Just 'cause...
DF