Both rifles will take down a moose. If weight is an issue, go with the lighter one.

Take the one you shoot the best and that you have the most confidence in. One that you know will survive the abuse airlines inflict and will still shoot true after being bounced around a boat/ATV through the snow, mud and rain for 3 days straight and you've just dragged it through a black spruce swamp to cut off a big bull before he gets in the water.

I promise you the last thing you'll be thinking at that moment is

"Gee, am I ever glad I saved 3lbs of weight"

I don't know what's on you packing list...but I'd send it to your outfitter and let him tell you what to bring and what to leave.

Some things that you might be able to do without:

"Extra" ammo. 20-25 rds should be plenty - how many shots are you really going to take up there.

Shooting sticks, bipod, tripod etc... (you can make them from willows once you're there)

Booze (did I really just say that?)

Extra knives

A reliable rifle would be pretty high on the "NEED" list and work everything else around it.

long time alaskan hunter here, take the ultra mag, it is the longest range hardest hitting off the shelf rifle available, on the last hour of the last day when you need the extra umf to deliver, its the one, i have regreted it both times i put it in the safe and grabbed a light gun, never again
chad

i agree with saskie, use the rifle you feel most confident with

I agree with replies. I currently am contracting in Savannah but my home is 27 miles NE of Fairbanks and I normally go every year. The lightest rifle I hunt with is a Weatherby 300 mag. I have a Ruger No.1 in 375 H&H mag that I use sometimes. I figure if I only have one shot I want to drop what I hit. I use an .06 for caribou. My wife bought me a Ruger .338 mag that I haven't used yet, mainly becasue it is SS and I prefer blue. When I get back I will wrap the barrel in camo tape. Should do the trick.
Kirk