270 Win and 270 WSM are pretty close ..I don't think there is 100 fps difference with the 130 grain bullet provided they both have 24" barrels. Plenty of Elk are killed with 270's every year although it would not be my first preference for that purpose. You can expect 2950-3000 with a 160 grain bullet in the 7 Rem mag and that will work although you may not see a noticeable if any increase in killing power over the 270's when used on Elk. I like the Sako 75 SS and think its a wise choice . I also own Remington BDL SS and like them as well in fact I just purchased one in 7 Rem mag. I don't think you can go wrong with either choice in rifles. I would also suggest a 7 WSM but your going to go Winchester or Browning in that chambering.