300 Win Mag for hunting moose at range

I want to get into longer range (than I am used to) shooting but wanted a caliber that can comfortably take moose at 700+ yards, I have often heard that 300 win mag is overkill and that 308 or 6.5 Creedmore is better but I don't think these people are considering moose. is 300 win mag overkill? what other calibers would be suitable? I want something relatively common for availability (I live in Alaska).