Anything from a .270, 30-06, 7mm, .300 and .338 will work. I watched my buddy drop a 50 inch moose last year with 1 shot from his .270 (not .270 WSM). As is always mentioned, shot placement is key.

I have shot all my bull elk with a 7mm, but this year have decided to upgrade to a .338 WM. Although my 7mm worked fine, through my experience with hunting partners and my own research I have found the .338 isideal for elk......if you can handle the recoil. Besides, I have a draw for bull moose in northen Alberta this year and decided that a .338 would be nice moose medicine.

The very lightest I would suggest would be a 30-06, but if you think you might be into some longer shots (300 yards plus) I would start with the 7mm and go up from there depending on what you are comfortable with.

Good luck in your decision and remember, the research and shopping part is half the fun.