[Mazryonh]

Note: I am NOT talking about converting semiautomatic-only firearms to fully automatic ones. I am only concerned with building fully-automatic weaponry from scratch.

If the "AK-47 is the most illegally manufactured assault rifle in the world," then just how difficult is it to manufacture them? Where are these illicit manufacturing facilities located? Just how low-tech can you get before you can't actually make them?

I remember reading how "crisis guns" like the British Sten or the Russian PPS-43 were manufactured with a minimum of high technology, but if they were so easy to make, I'm surprised that more people who want this kind of firepower (such as criminal gangs or insurgent groups) aren't making their own versions of weapons like these. Is it more difficult to make weapons like these than their reputations claim?

Supposedly, resistance groups in Axis territory made their own versions of the Sten in WWII. There are plenty of people now who handload their own cartridges or even manufacture their own bullets, so it can't be too difficult.