Gunpowder residue

I am simply a shell,
A bullet casing.
I expel my insides,
Leaving gunpowder residue at my lips.
And the bullet drives splinters out of wood,
Cracks into plaster.
Until all that is left,
All to show I was once full is the stark emptiness of the shell,
And the indent my insides made in the closest wall.

I am simply a shell,
A bullet casing.
Less full,
Less of me.
But I am less full.
And I am less of me.

I am simply a shell,
A bullet casing.
My model stays the same,
But the substance is gone.
The shot rings for a while,
It reverberates and clings to the ears.
“This is the last shot” it says,
But the dust settles and I am still a shell.
Simply a bullet casing.
For the next round,
And probably the one after that.