I prefer 600 yards max for deer in the 308. I would also take a shot on an elk or moose IF and only IF conditions were perfect including very still air and a perfect broadside double lung shot. If you put a bullet of adequete size and construction through both lungs and have enough velocity for it to reliably expand, either will expire. The key here is getting enough velocity to open the bullet properly. It is easy to get AMAX's and such to open at low speeds but these style of bullets are not muscular enough to do the job on moose or elk. You will need an ACCUBOND, Partition or similar to do the job.
You can get away with alot more with a bigger magnum such as less wind drift (less margin of error) and plenty of velocity to open bullets downtown. A 308 is really limited in its abilities to cleanly kill elk and moose downtown, but with the right conditions and the right load, it can be done.