[Cobra64]

There's no such thing as a "bullet casing."

It's a "cartridge CASE."

Casings are for sausage links and salami.

[TexasGator]

“There’s no such thing as a “bullet casing.”

You better send that to Guns and Ammo ...

http://www.gunsandammo.com/gun-culture/9-misused-gun-terms/