I was just called by a friend and asked if I knew anyone interested in a H&K bolt action chambered in "475 Magnum". I know about the 375 but can't find anything with the other designation... Is there such a thing as a 475 mag that is not a wildcat?

Ignorance may be bliss, but I find it frustrating, especially when it is my own...

There is certainly a 475 in the lists of old British double rifle cartridges, that's certain. Maybe that is what he means?

Then there's the Wildey Magnum. And I think they may be a 475 G & A lurking somewhere?

475 A&M (Atkinson & Marquart Rifle Co. of Prescott, AZ, 1958) is an old wildcat that a lot of wild claims were made about. It could never live up to those claims, but, it being a 460 Weatherby necked up to .475 caliber, it is powerful enough.
It has lesser case capacity than the 470 Mbogo, of Dave Estergaard in the late 1990's, a .416 Rigby blowout.

The .475 Ackley Magnum and .475 OKH are similar to the later 470 Capstick, .375 H&H blowouts.

Something very interesting is the .475 LTD (Lott-Tanner Dinosaur) of Jack Lott reported first in the 1972 Guns & Ammo Annual.
That is a .577 Nitro Express necked down with rim turned flush and extractor-groove cut for bolt action.
A lott like a .475/.505 Gibbs.

or 475 royale -- 505 gibbs, .475 bullet

I think so, a 475 A&M ! I saw one rifle of this caliber in the gun digest of 1960 , the first and the last !

H&K bolt action?

There's a .465 H&H. Might he be thinking of that?

LWD