While there are different kinds of assault rifles, AK 47 or Automatic Kalashnikov and SKS or Samozaryadnyi Karabin Sistemi Simonova are two popular examples. Although both are Russian made assault rifles, there are certain differences between the two. One of the major differences between the two is the fact that both were first designed by different individuals.
The design of AK 47 was done by Mikhail T Kalashnikov, while the design of SKS was done by Sergei Gavrilovich Simonov. SKS is the older of the two as it was the first to be designed, while AK 47 was first designed in 1947, which is three years after SKS was designed.
The under folding metal shoulder stash of AK 47 and its selective fire capability are two major features of AK 47, whereas SKS can only fire in semi-automatic. The selective fire capability of AK 47 makes it a better choice for combats.