Bolt or dart throwers are huge crossbows that shoot a spear-sized missile. They are so large that they are mounted on their own stand, often with wheels so they can be pivoted easily A crew of two or more is required to wind back the powerful torsion arms and position the huge bolt ready for firing. On the whole, these weapons are nowhere near as large or cumbersome as stone throwers and cannons.

Bolt throwers are fired in the Shooting phase along with other missile weapons. To fire a bolt thrower it must first be turned on the spot so that it points towards its intended victim. The bolt travels straight forward and (hopefully) hits the first target in its path. In a unit of troops this will always be a regular trooper. Only if there are no rank-and-file troops in the first rank hit by the bolt will it be necessary to randomize which model in the front rank is hit.

To determine whether the bolt strikes its target, roll a D6 to hit using the crew's BS in the same way as bow shots, crossbows, and other missile weapons. The usual modifiers apply, except no penalty is imposed for turning the machine, as it is designed to be used in this way. See the Shooting section for details.

If a hit is scored work our damage as described below. If the shot misses then the bolt hits the ground or sails into the air and comes down harmlessly somewhere else.