I just checked Winfer's book and you're correct, thanks. I picked this up yesterday at the auction.

According to Atkin, Grant and Lang, it was built Nov 26, 1902 as a 360 Cordite Rifle for A.H. Morris. The cost was 12 pounds.

I have an Evans double rifle in 400/360 and I love the cartridge.

I'll report more when I receive it.