kids these days!
there is no factual information that the german stg series or the mp series of assault rifles infuenced the soviet design of the kalashnikov.
the biggest influence that can be factually documented is the german group that was surrounded by russian troops and on the verge of annihilation.
the germans, in a daring airdrop operation, supplied the encircled unit with a quantity of the haenel/rheinmetal mp-44, 7.92x33 kurz (pistol patrone) assault rifles.
the germans managed to shoot their way out of the situation using their superior firepower...and very likely some good tactics and better luck.
needless to say, the lesson was not lost on the communists commanders...or front line soldiers for that matter!
remember, the russian round is called the "m-43". it was accepted for service in 1943 and in development years prior to that. the intermediate power cartridge was not a concept new to the russians.
in 1913-1916, the federov avtomat was the world's first assault rifle. it fired what was then considered an intermediate power cartridge...the 6.5x50.5 japanese ammunition.