New action needs a cartridge

[Larryjk]

If you aren't set on the truly big bore, I would recommend the 404 Jeffrey. I just have a thing for that cartridge. They are the equivalent of the 416 Rigby and are now loaded by Hornady to the same velocity of the 416. The bullet is a .423 and available from Hornady and Woodleigh. It is 400 grains in either solid or expanding. It is tapered so it looks like it wants to be improved but it should feed from the box magazine like a greased pig. They were much more popular in Africa than the Rigby until Robert Ruark wrote up the Rigby like it was magic.