Originally Posted by jpattersonnh
Casings are used to make sausage. Cases or brass are used to make cartridges. A puzzle? Wow! When it comes to things that go BOOM, don't eqaute it to a puzzle. Please.
casings plural of cas·ing (Noun)
1. A cover or shell that protects or encloses something: "a waterproof casing".
cases 3rd person singular present, plural of case
2. A container designed to hold or protect something.
I believe casing would be the best choice based on the definitions.
Also considering the amount of reloading suppliers that call them casings I would say that your attempt at being a smart ass was an epic fail.
Oh by the way its equate, not eqaute.