Fragment bolts are untradeable bolts fletched from bronze bolts and ascension fragments. They require 60 Fletching, and give 5 XP per 10 bolts made. Each action makes 15 sets of bolts, for a total of 150 fragment bolts per action.
Against Ascended, they are roughly equal to level 80 bolts. Against anything else, they are level 50. Damage is calculated starting as if the bolts were simply bronze, then adding a random amount approximately 460 (or up to 720 damage against Ascended) to each hit. This makes the hits lower than expected from level 80 ammo, but they're more consistent.
They require level 50 Ranged to use. They are single-use and are not retrieved by Ava's devices. Fragment bolts are not kept on death.