Editing Crossbow bolt (section)

=== Shaft ===
The [[arrow#Shaft|shaft]] is the main body of the bolt to which other parts of the bolt are attached. In modern times it is normally made of [[Carbon fiber reinforced polymer|carbon fibre]] or [[aluminium alloy]] (or sometimes both aluminum and carbon fibre are used), and is very lightweight for its [[Strength of materials|strength]]. Shafts come with varying degrees of [[stiffness]] — referred to as the "[[Arrow#Spine|spine]]" of the bolt. The more resistant to bending a bolt is, the more "spine" it is said to have, and a crossbow with higher [[Bow draw|draw]] weight ideally needs to be paired with a heavier bolt point and higher spine specifications. The weight of a shaft is usually in [[Grain (unit)|grain]]s, and product descriptions may provide the total weight in grains, or in [[grains per inch]] (GPI), for which the total weight of shaft can be calculated by multiplying the GPI value with length of shaft in inches.