The stuff isn't forbidden or owned? The dwarves can get to it? You have free dwarves with item hauling enabled? The dwarves can get to the destination stockpile? The stuff isn't on fire? (I think the dwarves no longer try to pick up stuff that is on fire.) The stuff doesn't have a monster sitting on it, scaring dwarves away? Do the stockpiles have weapons and armour, of all types, qualities and materials enabled?
I can't really think of anything else it could be.
Nope. Yup. I have 52 idlers, about 15 -dedicated- to hauling. Yes, its 1 Z-Level above, up the stairs. No it's not a fire. No monsters in my barracks. No, each is specified, easier to forbid the stuff I don't want them wearing.
Uhh.. I think I found the problem. Some leather shields (Shh, I made them on purpose.) were in the leather armour bin. Though I still don't know what the problem was with the bolts, my only marksmen ran all the way downstairs (3 Z-levels) got one stack and went up the to range until they were all gone. >_> Ahh well, thanks for the help!