identification - What are these shell case markings? - History

I have this shell case which was handed down in my family. We know very little about it and wondered if anyone can help identify the markings. I would be very grateful for any assistance.

Shell case marks - Arms and other weapons - The Great War (1914-1918) Forum

Shell identification - Other Equipment - The Great War (1914-1918) Forum

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Artillery shell cases, fuzes, primers and tubes. – Stephen Taylor, WW2 Relic Hunter

military - Can anyone tell me anything about the markings on these shell casings? - History Stack Exchange

identification - What are these shell case markings? - History Stack Exchange

Shell Identification / Story Authenticity - Arms and other weapons - The Great War (1914-1918) Forum

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Forensic firearm examination - Wikipedia

Large calibre markings (The Western Front Museum)

WW2 German, Soviet, Allied militaria, uniforms, awards, weapons history. War relics forum