I have not handloaded and fired a singel shot with the rifle. The cartridges fired so far has been suplied by Westley Richards after inspecting the gun.

I have however tried to chamber a factory loaded case after using a .318WR siezer die and because it was to disformed after firing it would not chamber.

I got the book you mention and assumed the disformed brass was because there where much more variations in chamber tolerances from rifle to rifle when it was made than now. This asumption was made as there has been none of the typical pressure signs like stuck brass or cratered primers.

You seem to have a lot of knowledge, so I will contact you further on pm if you dont mind:)