8mm French Ordnance revolver headstamp


I have an 8mm French cartridge headstamped “S.F 3 37 I” with the spacing lines in between. Who was the metal supplier “I”? Also, am I correct in thinking that “3” refers to the 3rd quarter of 1937?

Thanks for any info.


I = Société de Métallurgie Franco-Belge à Issy-les-Moulineaux

Some other headstamps


Thanks for that.