I think the 270 WSM is the only one of the new calibers that will survive over the long run. It is a nice package & offers some dandy performance. I have always thought the 7 mm Mag was over-rated, as it has just about nothing over a plain old 270 Win when the 270 is loaded where it was designed to be.
Most of any difference can be accounted for by the longer barrel found on the 7 mm Mags.
Bolt action rifles will just about always be more aaccurate off the shelf than an auto. I had a bolt in 35 Whelen that liked just about everything that I ran through it. I am working with an auto in the same caliber that is a lot more finicky, & never quite as accurate or consistant.
My 2 cents, get a bolt action in 270 WSM, and go hunting for anything in North America. With a good bullet, it will never disappoint you.