I do have a steel 75mm case but I got that from an American destroyer 35+ years ago when it visited the Bunbury port don't remember how I got from the crew to remove it off the ship but here it sits in my room.
The stencils on the bottom are practically illegible although the one on the side of the case says "Electrically Primed".

30three ran AMS through what codes I have no hits RCS may have a bigger list than I but the shell case looks in really nice condition good catch.