Ok not sure if a limited ammo mode is still planned but I think that it would be a good concept for hardcore mode players. as you can't realistically put one death games in this game.
So here are my ideas for limited ammo mode
first off add a backpack slot for all game modes, with this also limit people from going over 100% carry weight with out a pack.
Here are ideas for packs
light back pack
looks: team colored

limit: +50 carry weight
ammo: +2 mags/clips/loads (two reloads), +1 LMG mag, +0 micro gun, flasher, and standard MGL reloads.
RP cost: 5 RP respawn
Heavy backpack
looks: team colored

limit: +100 carry weight
ammo: +6 mags (most standard) +2 LMG mags, +1 microgun, flasher, and MGL reload
RP cost: 20 no respawn
AMMO PACK
looks:

limit: +0 carry weight
AMMO: +30 mags, +20 LMG mags, +10 migrogun, flasher and MGL reloads
RP cost: 200 rare no respawn
Note the backpacks would give a ammo boosts on top of standard ammo, and with out them a player can not carry more then 100% max weight. with them the standard backpack inaccuracy is active over 100% carry weight.
Now for the ammo part.
for this to work, there would need to be ammo crates and resupply vehicles and items that the PLAYER AND AI uses.
first off all players and AI would be limited to 4 mags/reloads of their main weapon, and 8 mags for any side arm pistol. Though backpacks and reload points will not reload the pistol a player would need to use an armory for that.
To reload their ammo supply the player will need to use (space) a ammo crate, by default these would use modified versions of the grenade crate textures, and all AI will go to them when out, a long with this, the armories and stashes would resupply ammo as well as player placed ammo points and a special supply vehicle.
PLAYER/ AI placed ammo crates
image:

info: reloads ammo to all that use it, has infinite uses but be warned when destroyed it will explode.
AMMO SUPPLY TRUCK
image

info: this would be a low health objective truck filled with ammo crates, unlike player and map placed supplies which have to be used, this will passively resupply all soldiers in an area, but be warned if it is destroyed you spawn with out spare mags, and must use a supply point to get your spare mags. But rejoice it does have a standard LMG of the faction on it, and can defend its self with about 1.6 (160) health.