world war one - What was this 1917 shell casing used for

Bought this shell from an antique store. Would like to know the history behind it, as in what it was used for? (The casing is about 16 and 1/2 inches in length)

Polte WWI 75mm Shell Casing - General Ammunition Discussion - International Ammunition Association Web Forum

World WAR 1 Trench Art Shell Casing Bullet Leaves Hammered Carved 1917 Paris, France - Canada

military - What kind of rifle used this shell case? - History Stack Exchange

Ww1 Brass Shell - Canada

Large calibre markings (The Western Front Museum)

Pair of WW1 British Brass Artillery Shells Dated 1917 For Sale at 1stDibs 1917 artillery shell, antique artillery shell for sale, ww1 shells for sale

First world war artillery shells hi-res stock photography and images - Alamy

1917 75 Mm Ww1 Mortar Shell Casing

Brass shell casing - 1917 - General Ammunition Discussion - International Ammunition Association Web Forum

1917 75 Mm Ww1 Mortar Shell Casing

Decoration from Destruction: the First World War Trench Art of Sapper Pearl

1917 Shell - Canada

Militaria : A collection of three German WWI artillery shell casings, comprising two 10cm Kanone 17

Shell (projectile) - Wikipedia