Far Cry 2 Edit
An Ammo Pile is a crate with which players can replenish their ammunition.
A typical Ammo Pile consists of three boxes of ammo (a small green container with a handle on it) placed on top a wooden crate. On the crate itself one can generally see the word "ammo" written in stencil. They restore ammo for non-explosive or incendiary-based weaponry available in the game, such as the AK-47 or the Dart Rifle. Strangely, even though individual ammo boxes one finds in other areas restore only one clip per gun each, each ammo box in the pile fully restores the player's ammo.
These can found scattered around the UAC (Unnamed African Country), namely at Safe Houses (if you have properly subverted enough main faction missions), militia checkpoints, towns, Weapon Shops and other places.
If damaged by a bullet or an explosion, an ammo pile will shoot out its contents in all directions, injuring or even killing anyone standing close-by. They will not explode if shot with a Dart Rifle, nor will they explode if the player hits them with a Molotov.
If an ammo pile is found (such as at a militia checkpoint) it will be marked on the player's map. This is most obvious for guard posts, where the icon on the map actually changes from a picture of a guard to three bullets, though it also appears when an ammo pile is found in towns or other marked areas, like Cock-Fights. The ammo pile symbol does not appear at Weapon Shops, since all Weapon Shops have them.
Far Cry 3 Edit
The Ammo Pile returns in Far Cry 3, however it can only be found in single player or co-op. The Map editor lets you place Ammo Piles but they can not be placed for use in multiplayer maps since it violates one of the map publishing restrictions.
Far Cry 4 Edit
Ammo piles also make a return in Far Cry 4, and function similarly to in the previous two games. The difference between the ones in Far Cry 2, and those in Far Cry 3-4, is that they also restore explosives, incendiary (flamethrower) ammo, and even bolts and arrows (for the auto-cross and bow weapons, respectively). They do NOT restore throwables of any sort however (bait, grenades, molotovs, knives). They can be found dotted around the map, as well as at certain locations on missions, and dotted around the roads on the convoy protection side missions. Also unlike in FC2, they only restore a portion of the players ammo (usually around 30-40% of it) for each weapon type, rather than all of it.