You're a bit off-target. All dwarves have to be assigned specific equipment to pick up--being assigned actual stacks of bolts is expected (and necessary). The real question is why the dwarf is unable to collect the stacks of bolts that were assigned. You can use the stocks screen (assuming you've set up a bookkeeper) to track down the problematic bolts in an attempt to resolve the issue; they might be outside of a burrow, locked in a forbidden quiver, carried by another dwarf, etc. Alternatively, you could make specific ammunition for your dwarf using "rare" materials (e.g. bismuth bronze), and set the ammo assignments appropriately to prevent the problematic bolt stacks from being assigned.
Hmm, so in my fort:
- No burrows defined
- One ammo stockpile
- No military dwarves using ranged weapons yet, so no one else should be moving ammo around
I have this repeatable behavior:
- Hunter shows idle, has crossbow & quiver but no bolts, military ammo screen shows bolts assigned. (I am not home right now, can't check the stocks menu. I do have a bookkeeper @ full precision.)
- Toggling hunting didn't help--turn it off, let him put equipment back, toggle on, he gets crossbow & quiver but not bolts.
- Clearing hunter ammo from military ammo screen & re-adding it doesn't help by itself; hunter still shows idle. I tried waiting a good while, still idle.
- Toggling hunting off after clearing the ammo, then toggling back on, did help. (I didn't have to wait for him to put equipment away, just to start heading off to the stockpile to do so, then turned hunting back on.)
- He gets his bolts and goes and hunts
- When he runs out of bolts, this whole thing repeats. Won't get new bolts until I clear the military ammo screen & re-add bolts for hunters, and also toggle hunting off on him til he starts to put equipment away, then toggle back on. At which point he will go hunt until the new set of bolts runs out, then this whole thing repeats again.