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Understanding Different Firearm Trigger Types and Actions

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Firearms are intricate machines composed of various components that work together to ensure proper functionality and safety. Among the critical components is the trigger assembly parts, which include the trigger and its associated parts. The trigger plays a vital role in initiating the firing sequence, making it one of the most important elements of any firearm.

Single-action (SA) trigger

The single-action (SA) trigger is one of the earliest and simplest trigger mechanisms. It functions by performing a single action when the trigger is pulled. In SA firearms, the trigger’s only function is to release the hammer or striker, which then impacts the firing pin, igniting the cartridge and firing the weapon. The trigger reset occurs when the shooter releases the trigger fully.

SA triggers are commonly found in classic revolvers and some semi-automatic pistols. Due to their light and consistent trigger pull, SA triggers are favored by precision shooters and enthusiasts who prioritize accuracy.

Double-action (DA) trigger

The double-action (DA) trigger, unlike the single-action trigger, performs two actions when the trigger is pulled. Pulling the trigger both cocks and releases the hammer or striker, leading to the firing of the weapon. The trigger reset occurs when the shooter releases the trigger only partway, allowing the hammer or striker to reset without firing the weapon.

DA triggers are prevalent in revolvers and certain semi-automatic pistols. They are known for their longer and heavier trigger pull, which can be advantageous in certain scenarios as it reduces the likelihood of accidental discharges. However, the longer trigger pull may require more practice for precise shooting.

Single-action/double-action (SA/DA) trigger

The single-action/double-action (SA/DA) trigger combines elements of both single-action and double-action triggers. These firearms allow the shooter to choose between single-action and double-action modes, providing greater versatility. In SA mode, the trigger performs a single action, much like a traditional SA trigger, offering a lighter and crisper pull. However, if the pistol is decocked or the hammer is uncocked, it transitions into DA mode, where the trigger performs the double-action sequence.

The SA/DA trigger is commonly found in semi-automatic pistols used by law enforcement and military personnel. It offers the advantage of a lighter SA pull for the first shot, followed by the option of subsequent shots in DA mode, reducing the need for manual cocking.

Striker-fired trigger

Striker-fired triggers are prevalent in modern semi-automatic pistols. Instead of utilizing a hammer, these pistols use a striker, a spring-loaded firing pin housed within the slide. When the trigger is pulled, it releases the striker, which then impacts the primer of the cartridge, causing the round to fire.

Striker-fired triggers are known for their consistent trigger pull, as they usually have a consistent weight and minimal travel distance. Many concealed carry pistols and duty firearms employ striker-fired mechanisms due to their simple design and enhanced safety features.

Double-action only (DAO) trigger

The double-action only (DAO) trigger is a variation of the DA trigger, wherein the pistol lacks a single-action option. Every trigger pull is in double-action mode, where the trigger performs both cocking and releasing the hammer or striker.

DAO triggers are often found in certain compact and subcompact semi-automatic pistols, especially those designed for concealed carry and self-defence purposes. The longer and heavier trigger pull in DAO pistols helps prevent accidental discharges and can provide added peace of mind for some users.


Understanding the various firearm trigger types and actions is crucial for any responsible gun owner or enthusiast. Each trigger mechanism has its unique advantages and applications, and choosing the right one depends on individual preferences, shooting purposes, and safety considerations.

When handling firearms, always prioritize safety and proper training. Familiarise yourself with the specific trigger mechanisms of your firearms, and practice regularly to become proficient and confident in your shooting abilities. Remember, responsible firearm ownership goes hand-in-hand with continuous education and adherence to local laws and regulations. Stay safe and enjoy the shooting sports responsibly.

Jordan Wayne, a psychology graduate from the University of Hertfordshire, has a keen interest in the fields of mental health, wellness, and lifestyle.

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