I've taken two Moose with a .308 180 grain. I don't know if it is fact or fiction but they seem to be more fragile than Deer, Moose seem to go into shock easier. Both went down in a pile, both were head on shots (or nearly head on), both were head up, low neck from the front. bullet ended up going through or very near the Heart.
Having said that, the trend seems to be higher velocities and smaller bullets. I don't really buy into that philosophy. I prefer big holes, a bullet that expands well and bruises as little meat as possible.