WP

I'm not sure if this is true for all quivers or not; the Ultimate Quiver is the only one I've ever used. I started with a pack weight of 272. I bought 600 bolts at the Resource Stone and my weight became 332. I added the bolts into the quiver and my pack weight became 372. The quiver added on 40 stones of weight for the same amount of items. I was planning on carrying the bolts in there to reduce my main pack clutter + I also wasn't sure if we received the Lower Ammo Cost if the ammo wasn't in the quiver.

And there's more. I tried adding the bolts to the quiver from the ground, without ever having had them in my main backpack. Long story short, every time you do that it permanently reduces the overall weight of your backpack by 1 stone and it is repeatable.