A trigger is the user-operated component of a firearm that starts the sequence leading to a shot. When the shooter exerts force on the trigger, internal parts release or activate the firing mechanism so a primer ignites a cartridge. Although often thought of as the small lever under the finger, the trigger is an assembly of parts and design choices that strongly affect safety and accuracy.
Basic parts and operation
A trigger typically connects to sears, hammers, firing pins or strikers inside the action. Pulling the trigger transfers motion through these linkages to release stored energy from a spring or hammer. Designers vary the geometry to control travel, break, and reset. For general background see additional reference or examples of finger interfaces at index-finger controls.
Common types
- Single-action: Trigger performs one function — releasing a cocked hammer or striker.
- Double-action: Trigger both cocks and releases the hammer or striker; may be double-action-only or combined with single-action capability.
- Striker-fired: Modern pistols use a striker mechanism with a consistent trigger pull.
- Two-stage and set triggers: Provide a light second break or a very light pull for precision shooting.
Manufacturers tune pull weight, travel, and reset to suit purpose: defensive, competition, or hunting. Terms such as "take-up," "creep," and "reset" describe how the trigger feels during use.
Safety, history and maintenance
Triggers are integral to safety systems. Many firearms include trigger safeties, transfer bars, or internal blocks to prevent accidental discharge if dropped. Historically, trigger mechanisms evolved from simple matchlocks and flintlocks to modern, repeatable designs that prioritize both reliability and controllability. Regular inspection, cleaning, and professional gunsmithing keep trigger assemblies functioning correctly and safely.