if the action is the same size and I fully think it is - as the ZKK602 - the .460 Weatherby is entirely possible if you want to be stuck with that case size. Would the .375 Ultra Mag be larger?

A person who I knew back in the 70's bought a .375 ZKK 602 BRNO - pulled the .375 barrel never fired (I bought it for $100.00 to re-barrel my .358 NMag.BRNO602)

He then had the action barreled up in .500 Barnes Supreme (on the blown-out .460 case), action work done and bolt opened up. It kicked too much for me - something like 120gr. of IMR3031 with a 600gr. Barnes IIRC - spun me around like a weather-cock. THAT part I well remember.
1/2 hour later, after recovering from that one shot, I went back to shooting my now .375H&H ZKK 602 and it felt like a triple deuce, compared to that bloody .50.