Pierre,
Thank you for allowing me to stir the pot a bit.
Your book does put all others on the subject to shame.
First edition quickly sold out?
So will the second.

Canuck,
Thanks for the additions, suggesting that:
The first barrel is about 15 years old and still going strong after all those annual safaris and shooting contests,
requiring wet towel cooling of barrel.
This cartridge must not be "over bore."
Just more evidence of perfection.

The drawing is correct at www.ammoguide.com demo here:

http://ammoguide.com/?catid=836

.375/404 Jeffery Saeed of 2012, aka .375-2012:

Cartridge brass maximum neck specifications: neck-1 and neck-2 diameters are .405".
Chamber reamer minimum specifications: neck-1 is .409", neck-2 is .408".
Throating then tapers down into the tight CIP-2001 throat of the .375 Weatherby Magnum,
which I have proven capable of excellent accuracy.

The only reamer specification we know of on the reamer used for the
".375/404 Jeffery Saeed Circa 1997" was a diameter of .408".

I am sure the .375-2012 will be a trouble free, smashing success.

Will add my load data at www.ammoguide.com as available.
Please refer to Saeed's load data until then.