I was thinking of the books I read years ago about USAF pilots who had to fly over North Korea and the dangers the faced. The only kit I’ve seen is the old Dragon one with three people around a small machine gun position. But I haven’t been able to find even information on what they had that could challenge the jet aircraft of that era.
Put a barrage zone of flak over a known target, and the laws of probability take over. Priority targets such as bridges, airfields, dams, etc. would be surrounded by AAA sites, some with radar controlled guns. Everything from 12.7mm heavy machine guns, up to 85mm or 100mm AAA of Soviet manufacture. Go in low, and you’re in the envelope of light automatic weapons up to 57mm. Go in high, and the heavy caliber stuff is the AAA of choice.
Doing some research I found that the ZPU-1 was used during the Korean War. Trouble is, the only maker of it I’ve seen is Meng as part of the 1990’s gun truck series. I do not know if that model of ZPU-1 is the same as the 1950’s version or not.