Being a newbie to Rokslide I hope I don't offend anyone, but .007" is not going to make any discernable difference to the elk if shooting quality bullets in both cartridges. When choosing which rifle to take between your two options, the headstamp on your brass is probably the most meaningless variable to your decision.
You should take the rifle that you shoot the best in FIELD POSITIONS, which is not always the one that shoots the best on the bench. Which rifle balances better in standing, sitting, and kneeling positon? Only you can decide that. Once you figure that out you will have your answer. With the two rifles you mention, balance and field handling will trump terminal ballistic gack and a pound or so of weight. If you truly feel you shoot them equally and they both balance the same, then take the lighter rifle. You won't kill anything if you can't put the bullet where it needs to go.
There's not a nickle difference between the 270 and 7mag with terminal performance with todays bullet choices, particularly if you're comparing a Partition to an Accubond. Both work well!