Hello,
I hope this will help you a bit.
SN 325L RS 16 p
SN: I can't find SN but maybe it is SM? SM: Socit Franaise des Munitions (industrie prive), Issy-les-Moulineaux
325L: lotnumber
RS: Atelier de construction de Rennes, Rennes
17: made in 1917
P: There are three possibilities: 1) Socit Anonyme des Mines et Fonderies de Pontgibaud, Pontgibaud 2) Socit franaise des Mtaux, Couran 3) Etablissements Planche (industrie prive)
MGM 776L 18 BX
MGM: Manufacture Gnrale de Munitions, Bourg-les-Valence
776L: lotnumber
18: made in 1918
BX: Socit Bendix, Clichy
triangle RS L365 14 P
triangle RS: Probably ARS? ARS: Atelier de construction de Rennes, Rennes
365L: lotnumber
14: made in 1914
P: There are three possibilities: 1) Socit Anonyme des Mines et Fonderies de Pontgibaud, Pontgibaud 2) Socit franaise des Mtaux, Couran 3) Etablissements Planche (industrie prive)
Mathias