I’ve seen printed loads for the 375 Weatherby 260 grain at 2900fps.
I have a 375 H&H AI which has a small amount of case capacity greater than the Weatherby, I would not likely try to get to 3,000 FPS with my 26” barreled rifle.
I can only imagine what pressure you’d need to get to 3,000 FPS and with a 260 grain bullet out of a 375 H&H.
I would not do it and I’d not recommend it!

I prefer classic.
Semper Fi
I used to run with the hare. Now I'm envious of the tortoise and I do my own stunts but rarely intentionally