Here is some reading:
6.5-284 Cartridge Guide
So far I have only tried H4350, H4831SC, 139 lapua, 142 SMK in a 29 inch krieger barrel.
139 lapua/ H4831sc combo is amazing accurate but didn't perform too well for us on a 575 yard deer last year. It ran about 400 yards into an area that we didn't find before the coyotes got him. No snow, it suct.
I suspect the Amaxes will work much better for that and will be working up a load in a few weeks. I will be working with 140Amax, H4831sc, CCIBR2 primers, Lapua brass. If it shoots bigger than 2 inches at 400, I will then be trying same components with H4350 instead as the powder choice.
H4831 may also work, but I have found H4831sc to work as well or better in the limited cartridges that I have compared it in.
Let us know how you make out.