"This isn’t to say that the sturmgewehr StG-44 didn’t make an impression on the Soviets: It’s difficult to imagine an enemy small arm that had as much impact on Soviet small arms design as the StG-44, but put into context the weapon represents more the proving out of a pre-existing idea than the introduction of something completely new."
They look similar, but the operating principle is significantly different. The STG-44 did have a huge impact on the Soviets, they learned a lot from it but operationally but not technically. Mikhail Kalashnikov took the concept, but the AK is not a modification of the STG-44 mechanically. That's a common misconception.
It's literally just a coincidence. The AK uses a totally different operating mechanism. The only similarity is the banana mag but that's just the reality of the cartridge dimensions.
Had a little known designer ripped off the STG44 the Soviets would not have adopted it in 1947. They would have laughed at it.
Not really. The bolt locks differently, but it uses a bolt carrier, gas piston, and buffer spring like an AK.
That said, the easiest way to dismiss the idea that an AK47 is a copy of the STG44 is to look at some of the gas operated rifles that preceded it in the Soviet Union, like the SKS, SVT-38, and AVS-36. Except the rotating bolt, they already had all the features of the AK in the 30's, and the rotating bolt is the one thing the STG44 doesn't have.
https://www.thefirearmblog.com/blog/2016/10/22/no-germans-di...