Trigger (firearms)
The trigger is a mechanical device found on firearms that initiates the firing sequence. It is typically a lever or button that, when actuated (pulled or pressed), releases the firearm's firing mechanism, allowing the hammer or striker to strike the primer of a cartridge, thus igniting the propellant and firing the projectile.
The trigger mechanism is a crucial component of firearm safety and function. Its design and operation directly impact the ease of firing the weapon, as well as its susceptibility to accidental discharge. Various trigger types exist, including:
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Single-action: In a single-action trigger, the hammer must be manually cocked before the trigger can be pulled to release it. This requires two distinct actions to fire the firearm.
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Double-action: In a double-action trigger, pulling the trigger performs both the cocking of the hammer and the release of the hammer, requiring only one action to fire the firearm.
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Single-action/double-action (SA/DA): This type of trigger mechanism allows for both single-action and double-action firing modes. The first shot is typically double-action, while subsequent shots are single-action.
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Trigger types also vary by their mechanical function: Many firearms feature different styles of trigger mechanisms, such as those using sear mechanisms, various types of springs, and other components to regulate the release of the firing pin.
The trigger's pull weight (the force required to actuate it) is an important consideration in firearm design and use. Heavier trigger pulls generally contribute to greater safety by reducing the chance of accidental discharge, while lighter pulls can improve accuracy and speed of firing but increase the risk of accidental discharge. Trigger pull characteristics such as take-up (the initial movement before the trigger breaks) and overtravel (movement after the trigger breaks) also contribute to the overall shooting experience and consistency.
Trigger mechanisms are subject to significant legal and regulatory restrictions. Laws concerning trigger designs and modifications vary greatly across jurisdictions, often focusing on the prevention of accidental discharges and the reduction of the risk of misuse. Understanding trigger mechanisms is critical for safe firearm handling, ownership, and operation.