Originally Posted by AK-47
Why are AK type rifles and SKS's always grouped together when they have nothing mechanically in common other than the round they fire? Sure, they are both gas piston operated but so are alot of other semi-auto rifles including some AR's.
Well, you started to answer your own question, but you should have kept going in your head before posting. As Robo said, both are from the same time period and both are Soviet weapons. In addition, both are still imported from similar geographic regions, both rifles are intended for the same purpose (short, mid range fire) and both are commonly desired by modern (similar) of shooters of common taste.
Plus Patrick Sweeney wrote a book tiled "The AK & SKS". What more do you want?