50 Beowulf, 6.5 Grendel and 300 BLK..same powder?

[cruddymutt]

Im working on 3 builds with the calibers listed in title. I see load data for 50 Beo and 300 BLK using Lil Gun powder but I haven't found one for 6.5 Grendel. With components being STILL hard to find is there a powder that I could use that would work for all 3? All 3 rifles are gas operated self loaders and I don't know what projectiles I am going to use yet.
The powders I keep stocked usually is 4896, 4064, and Varget (currently out).

Thanks

[Full Clip]

Maybe 1680?