The bullet only went 5-7 feet because he was using an AK 74 not a 47. Most people have no idea what an AK 74 is so it was easier to list it as what everyone thinks it was. The 74 uses a smaller round like an M 16 and gets its punch the same way, by tumbling when the round hits the body. If you go back you can see that very clearly in one of the slow motion shots that the round is going sideways towards the end.