Cartridge for double rifles. As can be seen in other British sporting cartridges, the .400 is a bit confusing, because this cartridge is not based on any existing .400″ case.
On p.50-51 of BRITISH SPORTING RIFLE CARTRIDGES by Bill Fleming, he makes a distinction between the 400/350 Nitro Express 2¾” and the 350 No. 2 Rigby. The case dimensions are given on p. 212, but for all practical purposes, the dimensions are the same. The differences between the two are too small to qualify this as two different calibers. The biggest variation between the two is .009” in the rim diameter on the maximum dimensions. Interesting however, is on p. 251 which shows the box codes. On all the specimens under the 350 No. 2, the only bullet weight is given as 225gr. This is also the same distinguishing feature on the loadings on p.50, whereas the 400/350 NE. is listed with a 310gr. loading except for one with a 288gr. loading by Roth.
Notice the long “dash” on the last two specimens
This is the 225gr. loading as listed by Fleming for the 350 Rigby No.2
The 350 Rigby No.2 is a seperate loading for the 400/350 and is not a seperate caliber.