Sometimes games tend to ignore the real and/or practical divisions in ammo types. In the case of non-specific ammo, all or some of the ammo found in the game is compatible with guns which in real life would have no business sharing ammunition. Often this concept allows the makers of the game to reduce the ammunition variety and/or allow more practical gameplay by sharing some weapons' ammunition.
The most obvious case of this would be in Team Fortress 2,
where the Heavy
character, holding a large Gatling gun will receive additional ammo for his weapon from a flamethrower left on the ground. It's this concept of interoperability between obviously different ammunition that shows in specific games one type of ammo can fit all.
The other example is the universal ammo, where all the weapons which use ammo have same ammo supply and allow the player to fire any weapon as long as there is ammo left in this main pool. Tron 2.0
and Deus Ex: Invisible War
are obvious examples of this, since a weapon can fire rockets, shells, arrows, disks and anything by using the said supply. The greatest inconvenience of this system is when one gun runs out of ammo, all of the others run out of ammo as well. The other rule of universal ammo is that sometimes a more powerful weapon will pull more ammo from the pool on a per shot basis than a less powerful one.
The ammo box / bag is an item that refills ammo for all weapons even if they use different ammunition, games like Team Fortress
, Serious Sam
and some other games use this kind of item. This can be practical in a way since we have to collect only one item to refill everything or almost everything. This doesn't necessarily exclude the option to have specific ammo supplies, but can simplify the process.