Mithril bolts (unf) are made by a player with level 53 Smithing using a mithril bar on an anvil. You get 10 mithril bolts(unf) for each mithril bar and gain 50 Smithing experience. At level 54 fletching, you can add feathers to make mithril bolts. Each bolt will grant 5 fletching experience. These are a popular choice when it comes to Smithing experience, with good experience rate at a fair price.
At current Grand Exchange prices, making 10 unfinished bolts out of a Mithril bar will earn the player 166 coins (3.32 coins per XP without bonus XP).
This is also a popular choice for players who are power-levelling Smithing at places such as the Blast Furnace and is considered to be one of the fastest methods of levelling smithing experience in game. As such, it is recommended to use bonus experience to save money due to the medium to high losses incurred. This item saw a drop in prices after the release of the quest Rocking Out. Also, you can buy the mithril ore and coal yourself and smith mithril bars using the blast furnace.A profit can be made making bolts from the bars and adding feathers and then selling them. Also, you can make them into emerald bolts and enchant them for even more money.
Some players choose to buy the bolts unfinished then buy the feathers to add onto them for Fletching experience. They then sell them on the Grand Exchange for highest price usually taking a few gp loss per 10 bolts.