I read about this the other day off The Firearm Blog.  This is the Mountain View Machine’ Pack-Rifle. This rifle weighs .97 pounds.  Less than a pound, and fires a .22 LR round. 

It can mount a laser and a scope, and can add a fishing pole accessory that allows you to fish with it too. 

Giving that is sells for $425 is pretty awesome considering you can hunt and fish with it, and it is less than a pound in weight.  I have never needed a pack rifle, but I think this could be useful.

Original Article: The 1 Pound Pack-Rifle (And Fishing Pole!) – The Firearm Blog