Maybe it's this one?

Jon Speed in ORIGINAL OBERNDORF SPORTING RIFLES shows a picture of:

"Double Square Bridge Magnum Mauser with 6x scope attached, made up in a 9.3x70mm wildcat cartridge based on a necked-down 10.75x73 mm (.404) case by Berlin gunsmith Ludwig Schiwy, expressly to order for Reichsmarschall Herman Göring. Note the front scope base bypasses the square receiver ring, in favour of a mount on the barrel shank".

Double triggers, adjustable cheekpiece, long barrel {26", 28"?} with sling swivel on the barrel. Family crest engraved on the magazine floorplate.

Not a fan of the man but his taste in this rifle is right on the money. Very workmanlike but tastefully done. Really a fine hunting rifle.