Would have 12gr. more capacity than the .300 H&H as that is what the .375 Ruger compared to the .375H&H has. This would quite likely put it about identical to the .300 WTBY, or between the .300 Win, Mag and .300 WTBY.
What about the .30 Nosler?
http://www.30nosler.com/

I find the claim of superiority over the .30 WTBY interesting as the Nosler book itself, lists 210gr. in WTBY as 3,008 and 3,038fps for top loads with the 210gr. bullet, which are identical or slightly higher than what they list for their .30 Nosler. Their add in the link shows differently, though. They must have hired CNN to do the add for them. lol.