Just made an interesting discovery at Eurosatory, after obtaining a couple of catalogues from the Chinese stand.
For some time there have been photos of Chinese Army 25mm automatic cannon on the net, and this has sparked some debate as to which ammo they were using: the old Russian 25x218, the NATO 25x137 or the Oerlikon KBB 25x184. One photo of the ammo I thought was misidentified, in that it looked exactly like the 23x152B Russian, with a sloping shoulder and a belt.
However, one of the catalogues has an illustration of the Chinese 25mm ammo - and it looks just like a scaled-up 23mm! This is the first I’ve heard of a new Chinese cannon cartridge, and is the first new automatic cannon cartridge to enter service since - well, several decades. I need to measure up the drawing precisely when I get home before I can calculate the case length and other dimensions. Fascinating stuff!