My First WWII Casing (4inch), ID?

[Bullet]

Hello all,

This is my first WWII Casing, it has a few marking on it 1943 / 4 Inch being the most obvious but as for the rest I'm not sure. I've seen online pictures 4 inch casings but none with the notched crimping at the tip.

Any help is muchly appreciated.

[spartanwarrior]

QF 4-inch naval gun Mk XIX? possibly

[Bullet]

Yes! It looks to be exactly that, the markings appear to show IV, XII, and XIX Guns. Any idea what M.E.C 161. Would the casing normally be marked with the Ships Identification?