WW2 half track: Questions about crew and ammunition. Can anyone please help me out? TIA

[Nick76S]

WWII M15A1 Half-track questions
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I'm trying to figure out some information on the crew and ammunition of the M15/M15A1 half-track during WW2 for the US Army.

[This T/O&E](https://imgur.com/GiD3IeB) from 11/17/1944 is for an AAA AW SP (Anti-Aircraft Artillery / Automatic Weapons / Self-Propelled) battery.

The M15A1 is assigned to the Automatic Weapons Squad (yellow column) and has a crew of 7 according to it and other online sources agree on the crew #.

* 1 Sergeant (Section Leader)
* 1 Corporal (Squad Leader)
* 3 PFC/Pvt (Cannoneer)
* 2 Tec 5 (Driver and a Gunner)

[This field manual](https://imgur.com/ooZdtah) (FM 4-159) shows the M15 seating layout:

* Driver + Squad Leader (Corporal) in the front seats.
* 2 Cannoneers on either side of the guns.
* 2 gun pointers
* 1 lead adjuster (Gunner)
* Squad Leader, Gunner, and Driver matches in both documents.

However, the T/O&E has 3 cannoneers and the FM has 2, so one of the cannoneers was a gun pointer? Also, where is the Sergeant (Section Leader)?

Did the corporal or the sergeant take on a gunner's duty? The corporal's MOS is actually the same as the lead adjuster (Gunner), so was he in one of the seats? If so, which one would be more likely? I'm trying to find out where the "Gunner" from the T/O&E would be seated, if not in the "Gunner" position in the FM then where?

In [this Wiki picture](https://upload.wikimedia.org/wikipedia/ ... kinawa.jpg) it shows the 7 crew with 2 of them looking out. The T/O&E says the driver was assigned the M1 Thompson/M3 Grease gun, but I thought it was usually the Sergeant that had it. Can't identify the ranks from the picture, but there are 7 people and a driver + 2 NCO, so one of them has to be on the gun.

Also as an aside, in the role of AAA AW SP in the European theater after D-Day, would the M15 be using [HE-T M54A1](https://imgur.com/TBAbMhS) exclusively in its 37mm M1 or would they also use [APC-T M59A1](https://imgur.com/BLNiy3T)? I know the anti-tank guns would have switched to be Bofors or something larger by then, so was the APC-T used at all for AAA purposes then?