I have a browning x-bolt long range hunter in a 300 win mag with a nightforce nx8 scope on it. I like this set up because the glass is really good and it doesn't have much more than recoil than a 6.5 creedmor
I would go with the kifaru straightjacket and their duplex lite frame. The straight jacket seems to be really versatile and you can do a lot more than just a day pack as well