Unreliable at the Boundary: Analysis of Two Sub-Optimum Crossbow Trigger Designs

Abstract

It is a fundamental principle that any weapon activated by a trigger — whether a crossbow, pistol, rifle, or shotgun — should only fire when the safety is set to the FIRE position, and the trigger is pulled. This study examines two distinct crossbow trigger designs associated with injuries. In the first crossbow, the trigger safety can be unintentionally or intentionally moved to an “intermediate” position (a point on the edge between SAFE and FIRE). This setting creates uncertainty, leading to instances where the crossbow discharges unexpectedly, either during arrow handling or even after sitting idle with no user action. In the second crossbow design, if the bowstring is not drawn with enough force, the safety fails to fully lock in place, resulting in the sear providing inadequate support to the corresponding release component. This creates a hazardous situation, observed to cause unintended discharge and injury to the user without any trigger activation. In both cases, the injuries did not stem from deliberate misuse; instead, the archer was operating the crossbow in a reasonable way that slightly deviated from the manufacturer’s intent.