[Part of my MMO Design Folder]
A minor detail that is often overlooked.
During the early days of MMO's (at least the first few I played), ammunition was always something tracked by the game. These days it seems ammunition is in such abundance that MMO's no longer track them. You have a gun? You can fire it. You have a bow? You can shoot it. Foreeeever.
I can see why they might have done it though. If ammo is an item then there are probably different versions of it, like fire, exploding, poison, etc. Then people will want to be able to craft it AND the various versions which will probably eventually lead to the "why does 1 plank of wood = 10 arrows or one chair" argument. Then players that focus on ammo dependent weapons will ask for ammo pouches, because it's unfair that their inventory slots (or weight restrictions) are taken up by bullets.
Instead, they change it into weapon skills - like in Guildwars 2 a thief can use a bouncy arrow or an arrow that poisons the area. Those options are available as long as he holds a bow and has unlocked those skills. If games really don't want to track ammo usage then perhaps they should make use of the Gamma World method more. For those who don't know what it is, it goes like this:
Ammunition: Bullets are a limited resource that you must use sparingly. In the D&D Gamma World game, ammunition is abstract: You either have ammo, or you don’t. If you do, you can use ammunition to fire any weapon you have that requires ammunition. If you don’t, you can’t.
If you use ammunition only once in an encounter: You are managing your ammo reserves carefully. At the end of the encounter, you still have ammunition.
If you use ammunition more than once in an encounter: You’re going whole hog—you might as well rock ‘n’ roll, because at the end of the encounter, you are out of ammo. You must acquire more before you can use a weapon that requires ammunition again (if you borrow some from an ally, then that ally is out of ammo.) Your Game Master determines when you find more ammo.
That design is more built around the scarcity of supplies in that game world and helping the players from doing much book keeping, but slightly modified I think it would suit any MMO and ammo would still be "a thing" players would need to care about. How I would translate it into a game is as follows:
Generic "Ammo" items need to be carried in your pack to use ranged weapons. It takes up one slot if we're using the slot mechanic for inventory, and should be reasonably expensive.
Each "ammo" box has a cool-down timer. Every time you fire it fills x% of the gauge (depending on the weapon). As long as you don't fire then the timer cools down back to 0. Stay calm and collected and in the green, and you can fire forever - but if your gauge gets over 100% then the timer turns red.
If you are on the red cool-down timer, that means you're not being careful with your ammo. You can go nuts and fire as much as you want for the next minute or two as the timer cools down. After which the ammo items are depleted and destroyed from your inventory.
What do you think? Is this a good idea or too much hassle? Should ammo instead go back to being tracked individually or do you feel that having an unlimited supply makes for a more enjoyable gaming experience?