I think most of the countries that made .303 kept with the (z) convention when using modern nitro powders. For example I have some S/A R1 M3z
that is not cordite.
The British loaded cordite for ever, denoting the change with the (z) suffix. I've had RG (Radway Green) from the late 50's that is still cordite.
Allan Quatermain: “Automatic rifles. Who in God's name has automatic rifles”?
Elderly Hunter: “That's dashed unsporting. Probably Belgium.”