Yeah, interesting stuff.
Graeme Wright mentions in his (first) book that the 350 No 2 was just a light loading of the 400-350 and that it shot a 225 grainer at about 2400 fps for a pressure of about 18.5 tons.
If that pressure is correct it makes you wonder how you could ever approach 2625 fps in that case!

Then there is the mention of that other cartridge, the 350 Rigby FLANGED MAGNUM!

400, if you have the time, check out a post I did some time back on page 2 of this forum titled Mystery 350 Rigby.

I'd be keen to hear your opinion and comments.