Parts of the Bolt
The Bolt is made up of four (4) parts, the shaft, the point, the nock and fletching.
The nock is generally made of plastic and is located on the end of the bolt, to help secure the bolt onto the crossbow string. There are two differing nock types used for both types of crossbows. The compound crossbow requires a half moon nock to better match the initial accelerated speed caused by the cam system.
The recurve crossbow requires a flat nock because of the continual increase in force that is transferred to the bolt once the trigger has been pulled.