The case shown looks as if it has been run into a 40/82 WIN die,(or other die) in order to “crimp” down the case to hold a Wad, possibly for a Blank Fire case, or an “Industrial Power Blank” used in Railway Bolt-hole Punches…a Tool used to Punch Bolt holes in the web of a Rail (Rotaia) to fit the Fishplates(Joiners) when doing an emergency repair. The type of shellcase ( raised head) fits the time frame for such tools, as these were used well before the introduction of Thermit Welding , as seen in the 1970s and 80s-restructuring of the FS Italia network with continuous-welded heavy rail.
(Thermit process: a Mixture of Magnesium metal, Aluminium metal, and Iron Oxide (Fe2O3) in very fine Powder Form, is packed into a small Furnace over a Clay form around the two ends of the rail to be joined; the mixture is ignited with a Magnesium strip Fuze…the resultant very high temperature causes the Iron oxide to be reduced to Liquid Iron, which runs down and Fusion-welds the pre-heated rail ends together…the Oxygen in the reaction combines with the Magnesium and Aluminium to form their respective oxides. The REACTION RELEASES LARGE AMOUNTS OF HEAT. When the whole thing has solidifed, the Furnace Funnel and the now hardened clay forms are removed, the Weld-mass cleaned up by High speed grinding, and the Joint is done.
Whilst the extra long lenghts of rail are usually joined by Butt Electrical welding in a factory, and the rails delivered in several Hundred metre lengths by a special Train of “rail” wagons, to be fed directly onto the rail bed, the ends of these long segments still have to be joined (to each other, to Switches( deviations etc) or to specially made “isolation Sections” ( specially joined small rail units which have an Insulated Joint for Signal Impulse transmission purposes))
The Thermit process was the basis of a Lot of Incendiary devices used in “Fire-Bombing” raids during WW II , the intense heat developed capable of burning through Sheet metal roofing, and even light masonry, and igniting almost anything combustible.
It could also be a Blank for a US-made Naval Line Throwing Gun They were made from Remington Rolling Blocks or Obsoleted Springfield Trapdoor Musket actions, right up to WW II.