What was the composition of a US Half-Track Unit during the Korean War?

Question

For some reason I remembered a conversation with my grandfather that I had at least 25 years ago. I knew he had been in Korea with the US Army and I asked what every young kid asks at some point: "Grandpa...what...what did you do?" The question I wanted the answer for was "what was your job?" I think it was taken as "what did you do to the enemy?"

He replied with, "I was a First Sargeant on a quad-50 Half-Track." He made a reference to airplanes which, I assumed at the time (and still do), was something to do with shooting them down. I don't know what else a half-track crew would have to do with airplanes if not that. But that was it. I remember sensing from his tone and short reply that it was not a topic to discuss further and we left it at that. To this day, nobody in our family knows what he did, where he was, or how long he was there. We do know that he hated the boat rides each way because he didn't know how to swim.

Now, the quad-50 halftrack was loved by the infantry and earned a nickname: Meat Chopper. You can guess why the infantry loved it and how it earned that name. So, knowing that, I can infer that he could have seen some action. None of it he would be eager to recollect, I'm sure.

My questions are:

1. what was the composition if a half-track unit in the early 1950s?
2. what were the numbers of officers and enlisted men in the units?
3. where would these units most likely have been sent?
4. which units would be so equipped (unit numbers, etc)?

There are really four questions here but I think they can all be part of a single answer.

Answer 1

The "quad-50 half-track" would have been an M16 anti-aircraft half-track. As such, he will presumably have served with an anti-aircraft unit; these seem to have been the only units employing these.

All of the eight US divisions had an automatic-weapons AAA battalion attached (originally just a single company in some cases, but later scaled up). A number of other battalions were sent to Korea in support roles - in total, there were eight divisional battalions and six independent ones. However, per that source, only the divisional battalion seem to have used the M16; the independent battalions may have used towed quad-mounts instead.

I have not been able to confirm the table of organisation for a Korean War battalion, but I believe it was the same as the organisation used late in World War II. If so, there is an overview of the battalion structure here (39 officers + 796 men, 16x multiple-mount .50" and 16x 40mm), plus a breakdown for the headquarters battery and the four gun batteries, although the second document seems a little confusingly laid out. A battery would have had six officers and 172 men.

The doctrinal manual setting out how these units should be used was FM 44-2 - again, unless this had been replaced by 1950. As you note, in Korea they were frequently used for ground support; chapter 8 (p. 93) sets out how this was expected to work.