Either is fine but I'd take the 7mm as my primary.

I've used, and observed the use of, the 7mm to harvest elk between from 180 (on the mountain) out to 500 (wide open valley) yards. My preferred bullets are 160gr Nosler Partitions (similar to the A-frame), and 160gr Accubonds. I've been forced to use 150gr bullets of lighter construction back when ammo and reloading supplies were hard to find and was seriously unimpressed with their performance. The 160gr NP and Accubond have always worked very well.

I'd be confident in the 270 if I knew there was no chance I'd have to take a longer shoot, say past 400 yards. Believe me though, when you pull a bullet out of something hit at 400+ yards, you realize the drastic difference in rifle-bullet performance at point blank vs. extended range. From my experience on with elk, I want to bring the most rifle I think I can carry all day in the mountains (slogging through 14 inches of powdery snow) in a caliber I think most efficiently retains energy for reliable expansion and deep penetration at any range I might shot. My personal current threshold on elk is 500 yards, and to that range I think the 7mm holds the advantage over the .270.

If I had the money to build an ideal elk rifle I'd opt for a light weight, accurized, 338 RUM or 338 Edge, (maybe even something in the .375 category), with a brake so that I could deliver even more energy for expansion and penetration at those 400+ ranges, where even our standard magnum chamberings start near the edge of their terminal performance threshold on elk.

Right now though I'd strongly advise you take your 7mm as your primary and your .270 as your backup unless your 7mm is too heavy to carry in elk hunting conditions or has some sort of accuracy problem.