Art, the ideal here is a one shot kill. If you can't make a good shot, you're not supposed to shoot at all. Indeed, big game hunters are required by law to search for wounded animals, including wounded game that wanders onto someone else's private property. If you fail to do your best to track down the animal and put it out of its misery (and "they" can prove it), you could lose your hunting permit for the next few years.
I've never heard of anyone shooting a moose in the head. Moose like most other game is shot through heart/lungs. I am not arguing for or against the use of specific calibers. My opinion on this or any other matter is just as irrelevant as Wildalaska's.
I'm just reporting the fact that a lot of people in my neighbourhood shoot a lot of moose and that many of them do it without magnum calibers.
Art, if your American moose have horns, they are indeed different from ours. Scandinavian moose have antlers.
We don't have what you call elk (wapiti deer). The confusion is probably caused by linguistics. The Norwegian name for the animal is "elg", in Swedish it's "älg", in German "Elch", the scientific name is Alces alces. The English name for the animal is elk. Since they don't have this animal in England, I assume that the first Englishman to see a wapiti deer in America said "This must be the elk I've heard stories about". Then the name stuck, and when someone who knew the difference discovered that there were "real" elk in America, it was too late, and someone came up with the name moose. Aha, I looked it up: The word moose comes from Algonquian. Anyway, elk in "UK English" is not the same animal as elk in "American English".
Scandinavian moose is the Alces alces. There are probably small differences from the American one, but it is basically the same animal. Our moose can have two types of antlers, both palmate and cervine, but it's still the same animal. I looked up the size to make sure: Norwegian bull moose can reach weights of 600 kg with a possibility of extremely large individuals reaching 800. In most cases they are much smaller, though.
I stole this from the 'net: