The only similarities between the Stg-44 and AK-47 are external cosmetics and the fact that they are gas operated. Kalashnikov used the rotating 2 lug bolt design from the M-1 Garand along with a tweaked version of the Garand trigger group. The Stg-44 used a falling block bolt lock system similar to the FN-FAL.
I saw an interview somewhere where he was talking about how brilliant the design of the M-1 was and how it affected his work.
Let’s see. Stg/AK:
Top gas tube - check.
Pistol grip - check.
Detachable mag - check.
Garand:
Top gas tube - No.
Pistol grip - No.
Detachable mag - No.
Sorry no sale. the AK’s basic design was ripped off with German help.
http://transsylvaniaphoenix.blogspot.com/2009/02/michail-kalashnikov-admits-german-help.html