I have no idea. I'd imagine that perhaps 400nitroexpress could give you better insight if it has been done. For sheer case capacity I'd imagine you would be up near the 577/500 Mag NE case capacity. I also have no idea on what ballistics or pressures would be for your desired ballistics.

On my own project I decided to listen to the voices of reason and build another 9.3x74r. I haven't given up on the idea of the 375 variant however or perhaps my own version of the 400 NE using a .408 bullet diameter. That would just be the 9.3 case basically straightend out. I think I'll just make myself 2 or 3 monoblocks and make myself other barrel sets for the same action.

Bill