Actually, John C. Garand designed the AK. Look at the FCG, same basic operating principle just layed out differently and simplified. Gas system? Turn the Garand upside down, relocate the port as was done with the M14 and what do ya get? Convert the op rod on a Garand into a bolt carrier, what do ya get? At the time, the Garand was the auto rifle to beat, why not adapt it to your needs? Of course the general layout/profile resembled the German STg43/44, most of the "assault rifles" that came after do too.