[Grognard]

Personally, when it comes to ammo, a large segment of the population will be... how shall I say... selfish.

In order to "cause" (ie force) the concept ammo dispensing to be anything but a subject of contention, it should be on a class that has, generally, less a reliance on ammo as its class' theme. It should go to a class, that ussually attracts a type of player, or someone in the mindframe to... be a support class. This way, the ammo will actually be "supplied", instead of greedily keep to themselves.

This leaves out:
MAX - class focus is ammo dependant.
HA - class focus is ammo dependant.
LA - class focus is ammo dependant.

So, candidates are:
INF - class focus is arguably non-ammo dependant, but the focus is often tactically lonewolf, so not a good choice.
MED - class focus is non-ammo dependant, but obviously as healers, they are already a huge target for focus fire. Giving them ammo resupply capability seems over the top, not to mention antithetical. Again, not a good choice.

This leaves my pick: Engineer.

1. Class focus is non-ammo dependant.
2. Support minded players are attracted to this class.
3. Resupply, and repair are not antithetical, rather complimentary.
4. They repair more than just vehicles, so should be interfaced with infantry also.
5. Nanites are already part of their tools, and are easily converted to ammo, too.

We can argue whether to have, or not have, player dispensed ammo at all, in another thread. However, for this thread, given that the mechanism is actually already in the game, and that the developers themselves already said they will likely move it to another class... That is the paradigm I am operating under here.