Call your .460 Weatherby a '.460 Weatherby Tropical or Light', download to 2350fps or there abouts & get under the supposed 10K Joule cut off.
If they can play funny buggers then why can't you?
Still no joy, shorten the chamber to 2.5" & there you have a .460 A-Square Short, still capable of pushing a 500gn bullet at over 2400fps.
Options I suppose!