Which version do you have? The Feather and the Flash have permanently attached buffer tubes so you will need a comspec adjustable stock to fit them. I have never seen a metal adjustable stock however, they are all made of a polymer. If you have one of the metal versions you can swap out the buffer tube for a milspec tube and use any milspec adjustable stock. There isn't much in the way of aluminum there either. If you want to go for a fixed or folding aluminum stock you would need a buffer tube to a 1913 adapter like in the link.
