Most of the M18 cartridge cases produced in Canada that I have seen were made under US Ordnance contract and shipped to the US to be loaded with American built shells/projectiles and assembled at US Ordnance Plants.
This one looks like it has a Canadian loading plant/Arsenal ink marking on the base. The ink mark looks like CO/C or possibly GO/C. Does anyone know what loading plant/arsenal those marks are from? I can't find a list of WW2 Canadian loading plants on the web.

This one looks like it has a Canadian loading plant/Arsenal ink marking on the base. The ink mark looks like CO/C or possibly GO/C. Does anyone know what loading plant/arsenal those marks are from? I can't find a list of WW2 Canadian loading plants on the web.
