The biggest in the pic is a 23mm AA cannon casing (Iraq should be full of these ones as well). I actually would have had a casing from a 30mm AA cannon as well but I forgot it when setting up the pic because it wasn't in the same place with these smaller ones.

But yeah, those are just some random mementos from my army times. I have an AA training, thus the AA related casings. Posting just a couple of Rambo dvd cases seemed like a boring idea so I thought to spice it up a bit.