Thanks Matthew. Where I'm from, sawed-off shotguns, as we call them, are illegal. I meant sod off shotgun as a false analogy to "sod off", an infelicitous and vulgar way to tell someone to go away. With a shotgun.
I'm picturing it as a movie that's a combination of Saw and Shaun of the Dead--I can see Shaun at his favorite pub, the Winchester, where he has to tell Jigsaw's victims to sod off because it's his turn to play pub games. Ooh! We could call him Sawn of the Dead.