Markings on bottom of shell casing : r/MilitaryHistory

Large calibre markings (The Western Front Museum)

File:3inchCaseShotMkVDiagram.jpg - Wikipedia

Markings on bottom of shell casing : r/MilitaryHistory

Headstamp - Wikipedia

WW1 Brass shell case - please help to identify - General Ammunition Discussion - International Ammunition Association Web Forum

Help identifying a shell casing from military funeral : r/guns

world war one - What are the markings on this shell casing

What do these markings tell me about this shell casing? I know

The Patriot: How Mark Milley Held the Line - The Atlantic

Navy Fighter Jets in the Red Sea Are Sporting Houthi Drone Kill

Armaments & Innovations - The Navy's 'Supershells' Naval History Magazine - February 2015 Volume 29, Number 1

Can anyone identify this shell casing? (More info in comments) : r

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

SHELL CASING MARKINGS - Arms and other weapons - The Great War

WW1 Photos & Info.