As I was looking into an AAA acting like regular unit as most as possible, except for targeting aircraft, I found this interesting post in my Quora account:
It was one of these:
That’s a 20mm autocannon on its trailer. You could either take the gun off and sit it on the ground or the back of a truck:
…or you could just keep it on the trailer and manhandle it. Obviously it was towed by a vehicle most of the time though. It’s called a Flak 30 or Flak 38 2cm gun.
It’s an automatic weapon firing about 5 high explosive 20mm rounds at you per second. 20-round box magazine. It can easily reach out and tag you from several hundred metres away. So yes, if someone points it at you you’re going to experience at best a very emotional moment in your life, at worst you’re going to get disassembled.
Technically you’re supposed to shoot down aeroplanes with it, and it does an ok job of that, but the Germans loved it to bits for infantry support too. They were the most-produced German gun of the war, reliable, punchy, manoeuvrable and available.