Halo K'NEX M7 Caseless SMG Model
This is a K'NEX model (just a model, not a gun) of the M7 Caseless Submachine Gun from Halo, better known as the SMG. It has twin notch sights, rear and fore stock, and a solid barrel. The stock is extended, the way I made it, but I'm thinking about making it collapsible. It should be fairly easy to put in a firing mechanism, but I don't plan on doing that right now. I don't think I'm gonna post instructions because I would have to take it apart. If anyone can dissect it in their minds, go ahead and make an Instructable, but make it a collaboration with me.
M7 Caseless SMG on Halopedia.org
High-Res M7 Caseless SMG