I was not certain that the .300 WSM or the .300 Rem SAUM case could be reamed for a Encore barrel, as their outside diameters are quite large, and once fitted would allow safe working pressures on thinner than normal chamber walls.
I guess the best way to go with such brass is to is to reduce the cartridge lengh enough (set-back the shoulder) that the volume of powder being burned will be used up close to the time the .416 bullet exits the bore. With these new brass cases available from several ammo companies, and all the new powders available to us nowadays, wild-catting using the right dies should give one just the ticket for large game animals...