I've taken big game (not Moose) with both the .300 and .338 Winchesters. I've used a 7mm Rem mag (1) and a .358 STA(3) for Moose. My British Columbia outfitter/guide chose hands downs the .300 Winchester for all his wilderness hunting. Why?, because the 300 had at extended ranges what the 'o6 had at the muzzle (remember also he lives in Grizzly country). I would choose it because of versatiliy. Your a handloader, so load it down to what others consider perfect (though not entirly true) for your cause, the '06. Want more power, load it up, with the bullet of your choice, to its true potential. Want pure boredom, get a good 180 gr bullet and watch things fall at all sane and some not so sane ranges. Some may feel the Big Magnum is to heavy or unwielding for hunting, I don't, but then again that wasn't the question. Your Moose "may" be taken in close, while your elk and deer can be taken at longer ranges. Exactly what the 300 Win is good for. A load I,ve "worked down" to take Wis and Mich Whiteails consists of a 165gr Hornady behind 53gr of IMR 4320, Fed215 primer for 2519 fps. That would be fired in my Winchester M70 Super Grade with 26" barrel, agian versatiliy. Enjoy your hunt, for a new rifle AND Moose. CRASH87