Found by me today. Never seen one before. Please help if you know something about it. You can see: SMI 936.
Societa Metallurgica Italiana, Campo Tizzoro, Italy 1936
This cartridge was used in various carbine and rifle versions of the Italian Carcano, as well as several light machine guns. In the first world war the Revelli heavy machine gun also used this cartridge, but I believe it had been supplanted in the Italian service by weapons chambered for their 8 m/m Breda (popularly called) cartridge. Jack