Both calibers will work fine. Personally I would choose the .270 over the 7mm-08 any day for any game or hunting. With the .270 you get more energy, higher velocity, more powder capacity, better trajectory and ballistics all around. And Woodleigh offers a 180 grain bullet in their infamous Weldcore bullet line for the .270. Double Tap has a load on their line of ammo with this Woodleigh Weldcore at, 2754 ft.lbs energy, and, 2625 fps velocity. And you honestly dont even need this heavy of a load for moose in a .270, but your friend seems to have an affinity for heavy loads. The sectional density for the 180 gr. .270 would be considerably higher than the 175 gr. load for the 7mm-08 due to the smaller bullet diameter and higher bullet weight, and the higher the sectional density the deeper the penetration. So I see no real advantage at all of a 7mm-08, especially for this purpose, its just going to punch a slightly wider hole in the moose, 7mm-08 (.284 diameter) .270 Winchester (.277 diameter) not a big difference. Plus your friend already has this .270 and I imagine has shot it and gotten to know the gun. So me like many other people have already said on this thread, why would he switch to a gun he is not familiar with? So the cons of switching to 7mm-08 are: Learning a new gun, loss of bullet energy, loss of bullet velocity, loss of sectional density, loss of trajectory and range capability (not that that will matter on a moose hunt), loss of powder capacity, loss of overall ballistics and trajectory in general. Pros of 7mm-08: Slightly bigger caliber (despite weaker ballistics), and short action rifle (at least I would say that is a pro due to my personal preferences).