JUNI 1917: The exact month and year the casing was manufactured. This places its production right during the height of the Western Front conflicts, matching the "Arras" battle commemorative engraving on the front.Rh. M.F.: Stands for Rheinische Munitionsfabrik, a prominent German ammunition and munitions factory located in Düsseldorf.St: Stamped near the upper left, this stands for Stark (strengthened). It indicates that the brass walls were structurally reinforced to withstand higher-pressure propellant charges.24: This is a batch, inspection, or factory lot number used for quality control tracking during wartime production.
