A double action (DA) trigger is a firearm mechanism that performs two actions with a single pull of the trigger: cocking the hammer and releasing the hammer to fire the round. This contrasts with single-action (SA) triggers, where the hammer must be cocked manually before the trigger is pulled to fire. Understanding the nuances of DA triggers is crucial for anyone interested in firearms, especially those considering purchasing a handgun or revolver.
How a Double Action Trigger Works
The mechanism behind a DA trigger involves a complex interplay of internal parts. When the trigger is pulled, the first part of the pull cycles the mechanism, cocking the hammer. This requires significantly more force than the second part of the trigger pull, which releases the hammer to strike the firing pin and ignite the cartridge. This two-stage pull is a defining characteristic of the double action system.
Think of it like this: Imagine winding a clock (cocking the hammer) and then pressing a button to release the spring (releasing the hammer to fire). Both actions are accomplished in one continuous trigger pull.
Advantages of Double Action Triggers
- Enhanced Safety: The heavier initial trigger pull acts as a built-in safety measure, requiring more force to initiate the firing sequence, reducing the likelihood of accidental discharges.
- Simplified Operation: The "ready-to-fire" state is readily achievable without manual manipulation of the hammer. This simplifies the process for new shooters and reduces the need for extra steps in a high-stress situation.
- Concealed Carry: The added safety and simplified operation make DA firearms popular choices for concealed carry. The hammer remains safely tucked away, lowering the chances of snagging on clothing.
- Reliability: DA triggers are generally considered more reliable than SA triggers, as they are less prone to malfunctions stemming from incomplete cocking or hammer drop.
Disadvantages of Double Action Triggers
- Heavier Trigger Pull: The longer, heavier trigger pull can affect accuracy and speed, especially for those unaccustomed to the mechanism. This can be particularly challenging during rapid fire or in self-defense scenarios.
- Longer Trigger Reset: The reset time, the distance the trigger needs to travel back after firing before it can be pulled again, is typically longer than in SA triggers. This can slow down the rate of fire.
- Less Precise: The heavier and longer pull can contribute to less precise shot placement, making it more challenging to achieve consistent accuracy.
Double Action Only (DAO) vs. Double Action/Single Action (DA/SA)
It's important to distinguish between two common types of double-action mechanisms:
Double Action Only (DAO): Every shot fired is a double action shot. The hammer is automatically cocked after each shot, but it remains hidden and never remains fully cocked.
Double Action/Single Action (DA/SA): The first shot is double action; the subsequent shots are single action, provided the hammer is manually cocked after the first shot (or through the operation of a decocker). This hybrid system allows for a lighter trigger pull after the first shot, increasing accuracy in follow-up shots.
Conclusion
Double action triggers represent a significant advancement in firearm technology. While they offer undeniable advantages in terms of safety and ease of use, they also present some drawbacks related to trigger pull weight and precision. Understanding these trade-offs is crucial in choosing the right firearm for your needs and skill level. Ultimately, the best type of trigger for you will depend on your individual preferences, shooting style, and intended use.
