+1 to this... I guess the first model of AK came out before the WWII and was not really tested in the combat. AK47, which is still widely in use, was launched after the WWII, in the end of 40's and is a much superior model.
Now, having had quite some exposure to AK47, I can assure you that it is the finest machine gun I have seen and precision is not bad at all. With tracer bullets you can see the same precision even after 4-5 rounds. Failing rate after 20 rounds is significantly high though.