AMMO RESUPPLY
Low ammo is not a problem in shorter scens, and squads will help each other out during play by sharing bullets if some guys run out.
Also the manual says units will automatically help themselves to any spare ammo in a halftrack/ truck if they're simply near it, they don't have to board it, but what they take will be fairly random.
But if you want to choose exactly what ammo to take, you have to board the halftrack/truck as below to get the popup list so you can choose exactly what you want them to take.
(The 66mm rounds are the HE Rifle Grenades, while the AT rounds are listed with the Zook rounds and zook launcher)
A 9-man squad (circled) and a halftrack-
The squad has got 707 rounds of M2 rifle ammo
I order them to area-fire into the ground for a few turns, and their rounds deplete to 456-
Selecting the halftrack shows it's carrying all kinds of spare ammo including M2 rifle rounds
So I run the squad back to board the halftrack, and hit 'Acquire'-
and a popup appears, so I select 8050 M2 rifle rounds-
and the squads stats show they've now got enough bullets to start WW3 and can get back in the war-
and the halftracks ammo readout now shows there are no more M2 rifle rounds on board, but it has some for M1 Carbines-