Diameter at web and at base are not the same per this drawing:

Base = .468"
Web = .465"

These dimensions differ slightly from the Municion.org spec's, as do diameters of bullet and case neck at mouth:

Case neck at mouth (outside dimension) - .380"
Projectile diameter at case mouth - .357"

Link to 'site: LoadData.com

This one lists rim diameter as .468", base diameter .464", neck .381" bullet diameter .358" jacketed, .359" cast: Gunboards

Reloading for the 9X56 is discussed here: AfricaHunting