A late 19th century cartridge used in NSW (Australia) Police Alexander Henry Carbines. I have seen it described as 2 1/2" or 2 5/16".
There are apparently two variations of this cartridge (cup and cannelure differences).
The only IAA Journal mention is in issue 384 Jul/Aug 1995 with a label and limited details along with a query.
Does anyone have more insight into this cartridge or pics of the two variations?