Ammunition, or ammo, is a game mechanic present in Pandemic's Star Wars: Battlefront and Star Wars: Battlefront II as well as Rebellion's Star Wars: Battlefront: Renegade Squadron and Star Wars: Battlefront: Elite Squadron that determines how much a weapon can be fired or used. All weapons rely on ammunition and it can be regained by picking up Ammunition Boxes or standing next to an Ammo Droid. Running out of ammo for a weapon means that the weapon cannot be used until more ammunition is regained. Some weapons, such as Lightsabers used by Heroes and Villains, have infinite ammo.
The amount of ammunition a weapon has is displayed next to the weapon's icon. Blaster-like weapons often have a lot of ammo, such as the Clone Trooper's DC-15 Blaster Rifle. These weapons fire in "clips" because of their high ammo capacity. Depleting a clip, the amount of which various from unit to unit, forces the player to reload, momentarily preventing them from using the weapon. For special weapons and gadgets, such as Mines or Detpacks, their "ammo" is the amount of times they can be used.
Standing near Ammo Droids or eliminating enemies and picking up the red-colored canisters left behind by them simultaneously replenishes all of the player's weapon ammo. For example, if the player were to pick up one Ammo Box while playing as a Stormtrooper, the player's E-11 Blaster Rifle would increase in ammunition as well as the amount of Thermal Detonators they could use.
Each weapon has a maximum amount of ammunition that it can hold, preventing the player from possibly accruing an exorbitant amount of Thermal Detonators.
Some weapons have unlimited ammo, such as Lightsabers. Other weapons, such as the Blaster Pistol for the Rebel Pilot, still have to reload despite having infinite ammo. The Clone Commander's Z-6 Chaingun has infinite ammo but builds up heat instead of having to reload.
Players can simulate having infinite ammo on weapons that do not have infinite ammo by standing next to an Ammo Droid and using that weapon. The Ammo Droid will instantly replenish the used ammo, but at the cost of the player constantly having to stand next to it, which is an often predictable and vulnerable location.