I'm thinking the ole H&H is pretty forgiving. RL-15 has been the standard forever.
I'd look at the burn rate chart, see what was close and what I could find. 4320 is discontinued, but should work if you could find some. 4064, LVR, CFE-223, Pw Pro 2000 LR (which some say is the same as CFE-223), H-380, Vv n-140, Norma 203B.
Big Game is pretty close and a great one in a number of rounds. I've heard it works in the .375 H&H. Haven't tried it in mine, yet.
Edited to add, of course, Varget would work. I save mine for specific loads, would use something else in my .375.
Last edited by Dirtfarmer; 01/19/21.