IME, which is pretty limited, moose are not all that difficult to kill.
My Dad has shot 3 shiras, all with a 300 winchester and 180 partitions, all one shot each at moderate range (120ish yards).
My Brother has killed on Shiras, also with a 300 and 180 partitions, one shot.
I've shot 2 shiras and 1 Alaska/Yukon. Shot one shiras with .338 and 200 grain ballistic tip, one shot. Shot one shiras with a 7 RM and 160 accubond, one shot. Killed the Alaska/Yukon with 7 RM and 160 partition one shot.
I wouldn't hesitate to shoot a moose with a .243 and 100 grain partition. A good friend of mine killed a cow in Montana with a 100 grain sierra from a .243, one shot.
Any decent cup and core bullet from a .30 caliber at reasonable velocity (2800ish) will work just fine, any controlled expansion bullet, probably even better.
No reason to over-think things.
Will probably kill my 3rd shiras moose this year with either my 7 RM and 160 accubond or perhaps my late grandfathers 300 WM (since both my Dad and Brother have killed moose with it, would be cool if we all shot one with the same rifle).