These weapons, except for wands, are equippable by hunters, rogues, and warriors in their ranged weapon slot. Wands can be used by mages, priests, and warlocks in their ranged weapon slot. No ranged weapon requires ammo, and they do not need any sort of recharge to continue working.
Except for wands, all ranged weapons have a short-range limitation in that they cannot be used on enemies in melee range.
Bows, guns, and crossbows require the Shoot ability, whereas thrown weapons require the Thrown ability. These two abilities are not interchangeable even though the ranged slot can accommodate both equally well. This means that if you equip a thrown weapon after having had a shooting weapon, you will have to switch to the Thrown ability (often bound to an Action Bar), instead of the Shoot ability.
Mentioned in contrast to melee weapons.