world war one - What's this 1917 shell casing, more exactly

I've been gifted this vase that is obviously made out of a large shell casing. It has 'MARZ 1917' stamped on the bottom, plus other less understandable markings: 'St', 'G', '36', 'HL 25'. I'm attac

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world war one - What's this 1917 shell casing, more exactly? - History Stack Exchange

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