The Firearm Blog has an interesting article refuting common arguments trying to support the idea that Germans, not Russians designed AK-47
Part 1: http://www.thefirearmblog.com/blog/2016/10/22/no-germans-didnt-design-ak-47-kalashnikov-conspiracy-theories-refute-part-1/
Part 2: http://www.thefirearmblog.com/blog/2016/10/23/kalashnikov-conspiracy-theories-refute-part-2-schmeisser-vs-mikhtim/
It's a topic that probably will be debated for a long time, as some won't accept that it is possible to have competitor's or other's design influencing. Maybe decades from now, people will talk about Glock vs other guns that have similar features.
From: The Firearm Blog