I've got some old steel jacketed Normas that I would use. Way back when Bob Peterson of Guns & Ammo fame went to Alaska, he used those on both a Brown Bear and a big alaskan moose. The 240 gr. bullet penetrated the moose almost all of the way lenthwise !
Any of the heavier jacket bullets that work well in the .444 should work. Even the 240 gr. stuff.
The 270 gr. Speer ? That's what I have to replace the Norma bullets.
Keep in mind that if you go to a different bullet, the gun's zero may well be quite different. E