I stand to be corrected if that is the case although I have never seen any 400gr loadings advertised in catalogues or books such as Ludwig Olson's "Mauser Bolt Rifles" which covers the field for the original loadings of RWS and DWM. I also spent a year in Germany and a lot of time with a hunting friend who had a vast collection of firearms, ammunition and catalogues in all the German calibres. Naturally i spent a lot of time looking over everything he had. It was he who gave me components for my .404, not the least a quantity of original RWS 347gr flat nose soft points which shoot very well in my .404.

The question I would have as I put in my earlier post is that the spec COAL for the 10.75x68 means a 400gr bullet would have to be seated very deep, impinging on the already limited powder space for the smallish cartridge case (small to bullet weight and diameter)or seated out to the extent that with the usual blunt nose of FMJ or soft nose bullets I could see difficulties arising with the throat or leade not being long enough. There is just such a difference between the 347gr and 400gr bullets. I have not come across any 400gr .423" bullets that did not have the crimping cannelure set for the .404 COAL so again if 400gr bullets were manufactured specially for the 10.75x68, I would imagine they would have a cannelure specifically set for that cartridge?

The bullet weight for 347grs should be shown as 22.5grams or 26grams for the 401gr bullet on any German manufactured ammo box for the 10.75x68. Can you confirm the gram weights?

I have loaded up a dummy 10.75x68 case with a 400gr bullet crimped at the cannelure and it sure looks a better cartridge that the original with it's stubby little bullet but of course making one such cartridge and getting it to fit an original 10.75x68 Mauser might be different.