john, I've read a couple ofarticles wherepeople used them on moose in Maine with great success.
For Alaskan moose I'd probably try & keep the range pretty short, but wouldn't back away there either.
I'm going to guess you'll loose60-100 fps with the shorter barrel. Personaly, I like a long barrel my self, just feels better & I've never felt that other 2" was in the way.
If you weren't getting the performance you desired you could always have it rechambered to 375 JDJ for a reasonable price.