Unfinished bronze bolts are bronze bolts before feathers are added. 10 unfinished bronze bolts can be smithed from a bronze bar, granting 12.5 Smithing experience and requiring a Smithing level of 3.
To finish unfinished bronze bolts, a player must add feathers. Attaching feathers to each bolt requires a Fletching level of 9 and 1 feather, granting .5 Fletching experience per bolt.