I have killed a few elk with Partitions out of my 300 Win Mag. My gun likes 70 grains of IMR4350 (Max according to my Nosler manual so don't start there!) and can shoot MOA with it. I switched from Noslers to Barnes a while back and they too have shown excellent results on big game.
I'm not a huge fan of "standard" cup and core bullets for elk. Elk are big tough creatures, and can travel great distances when wounded. With that said, if all I had was cup and core bullets to hunt with I'd still go, making very sure to choose my shot well.