Just speaking personally, I think the 6.5G is a autoloader round. I.E. for an AR15.
Again, just speaking personally, I wouldn't chamber a bolt action for it.
If I was shopping for a 6.5 round to put in a bolt, I would be looking at the new 6.5
Creedmore, the 6.5x47 or a 260 Rem. You could always go back to the 6.5x55, but if
this is a new gun, then the modern rounds might be a better bet.
You can read up on those last the here.
http://demigodllc.com/articles/6.5-shootout-260-6.5x47-6.5-creedmoor/
As for the life of the 6.5 G for the AR, I would say it is going to get some tough competition from
people necking down the .30 AR to 6.5. That said, given the limitations of bolt thrust on the AR rifle,
I wouldn't think that you will see much difference in energy between the respective rounds. The 6.5 G
also allows double stack mags that the 30 AR won't.