Holmes, You are almost right about the cartridge. Here are the facts from Krieghoffs website.
---------------------------------------------------------------------

Rimmed Cartridge .500/.416 Nitro Express (3 1/4").
Because the ideal combination for dangerous game is a big bore double rifle chambered for a rimmed cartridge, Krieghoff has joined forces with WR Ammunition Company (Wolfgang Romey), the world renowned German specialist in big bore ammunition, to develop a new flanged cartridge - the .500/.416 Nitro Express (3 1/4").
The designation says it all. It is a 3 1/4" .500 caliber case and a .416 bullet - components which are popular throughout the world and readily available everywhere.

The ballistics are perfect for the use on dangerous game, similar to the famed .416 Rigby, but with the supreme advantage of a flanged cartridge.

The .500/.416 N.E. (3 1/4") provides:

Reliable extraction.
Simple construction using readily available components.
Maximum effectiveness with moderate pressure. Velocity and
energy are similar to the belted .416 calibers, such as the .416 Rigby.

These characteristics combined with its high energy and flat trajectory suggest that the .500/.416 N.E. (3 1/4") is itself destined to become a 'classic' member of the big bore cartridge family.

-----------------------------------------------------------------------

I tried out the balance of a couple of different guns and the Blaser was outstanding. I will post pictures as soon as I get it. There has been some complains at the saftey which goes back to safe when the gun is broken but since I have the same on my Drilling I don't think that is a problem even in dangerous situations, Everything has to do with practising.