Where are you going moose hunting? Why do you need to shoot 3-400 yards? Most moose, even in the western US are shot close, 200 yards or less. I think either would work. Which do you shoot better? I like the Whelen myself. Just couldn't do the 7mm because everyone else did. Sneak close, blow the heart and lungs out and you'll have moose meat.
Dr Fatguy