Duckslayer89, I have some friends that hunt with Ambush Outfitters every other year. They go up as a group of 6-8 and the success rate is about 50%.
If you look at the pictures of moose harvests the third one down on the left has their group. They have shot moose from 100 - 600 yards.
I don't know if you shoot with a muzzle break but the outfitter does not like them and prefers not to have them on the hunt.