Trigger (firearms)

A trigger is a small lever.

You push it with your finger. It lets out a lot of energy. This can make a tool or a gun work.

Inside, a spring holds a lot of power. The trigger lets that power go. This makes a metal part swing forward.

This part hits a small pin. That pin hits a tiny spark. The spark starts a small blast. This blast pushes a piece out.

Some triggers are simple. They only do one job. Other triggers do two jobs. They can even cock the part for you.

Triggers can be shaped many ways. Some look like buttons. Others look like a bar to squeeze. It is a very smart part.

A trigger is a part that starts a machine. It can be a lever for a gun. It can also be a switch for a power tool.

A trigger works by letting out stored power. Inside, a spring holds energy. The trigger releases a part called a sear. The sear holds back a hammer or a striker. A hammer is a metal part that swings like a mallet. A striker is a pin that is pushed by a spring.

When the trigger is pulled, three steps happen. First is the takeup. This is the movement before the sear moves. Next is the break. This is when the resistance suddenly drops. Finally, there is overtravel. This is the movement after the part is released.

Some triggers do one job. These are called single-action triggers. They only release the hammer. Other triggers do two jobs. These are called double-action triggers. They cock the hammer and release it. This can happen in one pull.

A trigger is a mechanism that starts a machine. It can be part of a firearm, an airgun, or even a crossbow. The word also describes a switch for other things like power tools or traps.

Most triggers use a small lever called a trigger blade. A finger presses this blade to release a lot of stored energy. This tiny bit of movement leads to a much larger action. It is the starting point for everything the device does.

To understand how it works, we must look at the internal steps. A trigger works by releasing a part called a sear. The sear holds back a spring that has stored elastic energy.

There are two main ways to strike the cartridge. A hammer is a metal part that swings forward like a mallet. A striker is a pin that is pushed directly by a spring. When the sear is released, the hammer or striker hits a primer to start the shot.

When you pull a trigger, you feel three distinct mechanical stages. The first stage is called takeup, or pretravel. This is the movement of the trigger before the sear actually moves.

The second stage is the break. This is when the resistance suddenly drops as the sear releases. The final stage is overtravel. This is the extra movement that happens after the part has already been released.

Triggers are often grouped by how many jobs they do. A single-action trigger only performs one function. It only releases the hammer or striker. For this to work, the user must cock the weapon by a separate way.

A double-action trigger does two jobs at once. It both cocks the hammer and releases it in one single motion. Some modern pistols use a hybrid design that does both.

People use different triggers depending on what they are doing. Single-stage triggers are popular for hunting because they have no resistance during the takeup. Two-stage triggers are popular for competition rifles. These are often called pressure triggers. They have a light resistance during the takeup, followed by a much heavier resistance during the break. This allows a shooter to ease into the pull carefully.

{ "text": "A trigger is a mechanism used to actuate a ranged weapon or device. This includes firearms, airguns, crossbows, and spearguns. The term also describes switches that initiate other tools, such as power tools or traps.

At its core, a trigger allows a small amount of energy to release a much larger amount of energy. While people often use the word to describe the visible trigger blade, it technically refers to the entire trigger group. This group contains all the internal parts that work together to start the firing process.\n\nTo understand how a firearm fires, we must look at the internal chain of events. The process begins when a user applies force to the trigger. This force moves the trigger to release a component called the sear. The sear is the interface that holds the hammer or striker under tension.

Once the sear is disengaged, the stored elastic energy in a mainspring is released. This energy is transmitted through an intermediate mechanism to a striking device. This device then hits the cartridge primer, which contains shock-sensitive compounds like lead styphnate. The resulting spark ignites the propellant powder, discharging the projectile.\n\nThere are two primary types of striking mechanisms used in this process. The first is a hammer, which is a pivoting metallic component. When released, it swings forward like a mallet hitting a chisel to strike a firing pin. The second type is a striker, which is essentially a firing pin loaded directly to a spring. A striker eliminates the need for a separate hammer because it moves forward along its own axis. Both methods rely on the sudden transfer of kinetic energy to ignite the cartridge.\n\nWhen a person pulls a trigger, they experience three distinct mechanical stages. The first stage is known as takeup, or pretravel. This is the movement of the trigger before the sear begins to move.

The second stage is the break. This occurs when the sear reaches its release point and the felt resistance suddenly decreases. The third stage is overtravel. This is the residual movement of the trigger after the sear has already released. Overtravel can be important for accuracy, especially in firearms with long barrels or heavy trigger weights.\n\nTriggers are often categorized by how they feel during these stages. Single-stage triggers, or direct triggers, have no discernible resistance during the takeup. They only encounter resistance at the very end, often called \"the wall.\" These are popular for hunting. Two-stage triggers, or pressure triggers, are common in competition rifles. These have a light resistance during takeup, followed by a much heavier resistance during the break. This allows a shooter to \"ease into\" the pull to maintain accuracy.\n\nThe amount of force required to overcome the sear during the break is called the trigger weight. This weight is measured using various units, such as newtons in SI units or pounds and ounces in US customary units. A slow, heavy trigger break is sometimes called a \"creep,\" which is often viewed as an unfavorable feature. Conversely, some shooters prefer a \"crisp\" break, which features a heavier weight and very little movement.

Controlling these forces is vital for preventing unwanted shakes at the instant of firing.\n\nTriggers are also classified by their \"action," or the number of functions they perform. A single-action (SA) trigger performs only one task: releasing the hammer or striker. In these systems, the user must cock the weapon through a separate action. This design was common in 19th-century revolvers like the Colt Model 1873 Single Action Army. In contrast, a double-action (DAO) trigger must both cock and release the hammer in one continuous motion. This requires more force because the trigger must perform two jobs for every single shot.\n\nModern firearms often use hybrid designs known as DA/SA. These pistols function in double-action mode for the first shot, allowing the weapon to be carried safely with a lowered hammer. After the first shot, the slide automatically recocks the hammer, and subsequent shots are fired in single-action mode. This evolution began in the late 1930s with models like the Walther P38. These systems combine the safety of a double-action start with the lighter pull of a single-action finish.", "media": [ "File:Trigger mechanism bf 1923.jpg", "File:Thompson submachine gun Firecontrols.jpg", "File:MG 34 trigger RCR Museum noBG.jpg" ] }