Sounds like the .470 Capstick would have also been a good choice for you

(I don’t get why it’s not more popular?)
Krish, a fellow member here did offer one, but I ended up buying a factory new CZ550 receiver he had with a 416 Rigby bolt face. I knew in my heart that it wanted to be a 450 Rigby when it grew up.
Kenny Jarrett is building my rifle, and he, along with the Rigby Co. developed the 450 Rigby. Kenny worked out the reamers, dies and built the first rifle in this caliber. The drawings for the cartridge were provided to Kenny by Paul Roberts, who owned Rigby at the time.
I asked Kenny about the 450 Rigbys performance on game, and he spent the next 30 minutes describing his hunting experience in Africa with it. It archived total penetration on all broadside shots, including brain shots on Elephant. In his words, there is a noticeable difference between the 458 Win, and the 450 Rigby.
I also talked briefly with Craig Boddington at the SCI this year about the rifle Kenny was building for me. His opinion is that all Dangerous Game responds to higher power levels, IF the shooter can handle the recoil, IF the bullet is adequate for the higher velocity, and IF that bullet is placed where it needs to go. He has a very favorable opinion of the 450 Rigby for Dangerous Game.
This is my PH Christo Van Dewnter, owner of Alpha Pride Safari's and one of his rental rifles is a factory CZ550 in 450 Rigby. I've discussed DG hunting with him at length and when I asked him specifically about the added power level of the Rigby his response was yes, there was clearly a difference on game. With the Swift A-Frame or the Barnes X, he believes it to be a true stomper on Dangerous Game.
The problem with many rifles, especially the Weatherby's is rifle weight vs power level. The factory Weatherby MKV in 460 is listed on their website as 9.5 pounds. It should weigh at least a pound heavier, and an added 2 pounds would make recoil less severe. The problem is most of us don't want to carry an 11pound rifle very far if we don't have to.
Which brings us to this ...
My 450 Rigby rifle currently under construction. With the Swaro Z8i it will weigh over 11 pounds. Will it be the finest Dangerous Game rifle in Africa? Can it cure all the faults of the 460 Weatherby and MKV rifle combination as
@grand veneur stated in his post? I believe it will. Stay tuned for future hunt reports.