You start with less ammo (3 clips I believe), and you only auto heal up to 50% health. To revive to 100%, you need to have a health pack in your inventory. To get a health pack, you either need to be given one by a medic, who has infinite health packs, or you need to pick one up from a flag base, which has ammo and health stations.
The system is more complicated, but it's honestly a welcome change. It makes the game feel more tactical, less arcadey, and promotes teamwork more.
2 magazines for the STG44 and you can pick up a third magazine from a support or ammo cache. ---