[Vaquero]

It's certainly pushing a heavier bullet then either a 30-06 or .308 so I would imagine that the powder capacity is greater then either of those cartridges.

it is not.

those heavy bullets cannot maintain the velocity for more than short ranges....

and my preferences are for M1 Garands, 1903
springfields and Trapdoor Springfields....nice big cases...
but if I was going into battle I would defer to at least a .308 size case for weight and volume carrying ability.

Now if I really wanted to carry a .50....it would be a semi-auto Barrett in .50BMG....now that's a rifle....

[Durus]

The total case capacity for a .50 beowulf is 70.3 grains while the total capacity of the .308 is 56 grains. That being said there isn't much dispute that the .308 has much better long range ballistics.

If I were going into battle and no considerations were taken in account(such as availability) other then sheer performance and weight it would be the 6.5 grendel. It can do anything the .308 can do and you can carry more of it.

The .50 BMG is one heck of a round and the Barrett company makes some fine rifles. So many guns...so little money.