Why a 6.5 Grendel in a bolt action?

[BjornF16]

Here is a comparison of the Savage .308 and 7.62x39 DBMs. (Top is .308)

I can place the .308 DBM into my Grendel, and the 7.62x39 DBM will fit into my Savage .308 rifle. The .308 would not hold multiple Grendel rounds without modification.