The term rate of fire is used when measuring the frequency at which a firearm can expel a projectile. In most cases, the rate of fire is determined by the skills of the shooter. For example, there is no set rate of fire for a bolt-action rifle—it is a function of the shooter’s ability to cycle the action and pull the trigger. With fully automatic firearms, however, the rate of fire is a measure of the mechanical ability of the firearm to cycle and fire a round multiple times with one press of the trigger. This is measured in rounds per minute.