Grandson hit a doe behind the right shoulder at abut 125 yards Saturday evening. Problem is the deer was quartering toward him so he only got a piece of one lung and ALL the stomach. Deer ran less than 100 yards with little blood trail and toppled over. Fortunately, they were able to mark the fall in the 5' tall CRP grass or recovery would have been impossible. The bullet isn't at fault for the placement and it did a lot of damage with at least 18" of penetration. Ammo used was Federal MSR 123(?) grain. We didn't have the opportunity to test the Hornady 123 SST which I would expect to be a bit more violent in expansion. Maybe next year.
From my perspective, the 6.5Grendel is an adequate 150-200 yards deer round. I still prefer the 6.8 SPC based on the simple fact that I've found the 6.8 to be more generous in regards to the ammo choices. Our 6.8's seem to shoot anything from 90-115 grains with similar accuracy while the 6.5 G appears to be mostly a "one trick pony" with accuracy all over the board except for it's "preferred" ammo.
I'll probably buy a 6.5G bolt action if I can find one within the next year simply because it's nearly impossible to find a 6.8 in a light, compact package suitable for the kid use.