The 7RM is definitely a step up from a 270.
If you are looking at a dedicated elk hunting rifle look at the 300 mag or 300rum.
With the same velocity the 270 shoots a 140-150, the 7RM a 160, and the 300 a 190-210.
That being said a 300 isn't going to drop elk on the spot without perfect shot placement any better than a 270...the elk will probably go a lot shorter distance though and leave a blood trail.
That being said I usually hunt elk with a 270WSM.