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Binary Triggers Explained

Do you like to shoot your semiautomatic firearms rapidly? What if we told you that a particular type of semiautomatic trigger contains technology to allow even faster shooting? Binary triggers are a groundbreaking firearms accessory allowing just that, faster semiautomatic firing. Several manufacturers make binary triggers to fit many modern semiautomatic firearms on the market. While some guns come from the factory with binary triggers installed, folks usually insert them as an aftermarket accessory. 

What is a Binary Trigger?

Binary triggers are semiautomatic triggers that feature two modes of firing, semiautomatic and binary. The semiautomatic setting in a binary trigger is just like any other semiautomatic trigger. When someone shoots a firearm in semiautomatic, a single round fires for each pull of the trigger.  

The secondary mode in a binary trigger is the binary setting. In binary mode, one round fires when the shooter pulls the trigger and another round fires when the trigger is released. If you aren’t interested in shooting binary that day but have a binary trigger, there’s no need to worry. You can simply move the selector to semiautomatic mode and avoid binary altogether. 

Fostech Echo AR Trigger.

How do Binary Triggers Work?

When one pulls the trigger in the semiautomatic mode, the sear drops to release the hammer which strikes the firing pin. After firing, the hammer recocks, and the disconnector holds the trigger in the rearward position (preventing automatic fire). When the trigger is released, the disconnector releases the hammer and the sear catches the hammer. At this point, the trigger is ready to fire again. 

The root of binary is bi, meaning two. Binary triggers use two sears and give two shots for two trigger movements. After firing, the hammer recocks and the disconnector grabs the hammer to restrict automatic fire. Before the trigger is released, a secondary sear grabs the hammer. When the trigger is released, the second sear drops to release the hammer to fire the next round. If the trigger is in binary mode, and the shooter does not want the release to result in a second shot, they can switch back to the semiautomatic setting. 

Fostech Echo Sport AR Trigger. The Echo Sport uses an external paddle to select echo (binary) mode verses using the selector.

Are Binary Triggers Legal?

As of this publication, yes binary triggers are legal according to the Bureau of Alcohol Tobacco and Firearms (BATF). This yes answer counts on the Federal level, however, make sure to check your state and local laws. Because each trigger movement in binary mode is distinct and results in only one shot per trigger movement, binary still counts as semiautomatic. In fully automatic firearms, multiple rounds fire with a single trigger pull and the firearm continues to fire until the ammunition is gone or the trigger is released. 

Franklin Armory AR Binary Trigger.

What are Uses for a Binary Trigger?

Binary triggers have several uses other than good old fashioned fun at the range. The binary trigger offers real benefits in a competitive shooting environment. In addition to shot placement, speed is the second most important factor in competition shooting. For competitions that allow binary triggers, they are a considerable advantage due to how many shots one can make in such a short amount of time.

Home defense is another excellent use for binary triggers. Defensive shootings happen very quickly and usually, only involve a few shots. One must take those shots very rapidly and binary mode increases the firepower since each motion of the trigger results in a bullet fired. 

Franklin Armory HK Style Roller Delayed Blowback Binary Trigger.

Who Makes Binary Triggers?

Franklin Armory coined the term binary trigger, and due to their popularity, it is nearly an industry-wide term for similar two-mode semiautomatic triggers. In addition to binary AR triggers, Franklin Armory also makes binary triggers for CZ Evo Scorpions, AKs, H&K G3 type rifles and the Bushmaster ACR. Another company by the name of Fostech makes binary-type triggers for ARs as well. Both brands’ products are proven and reliable to sling plenty of lead downrange. 

Franklin Armory CZ Evo Scorpion Binary Trigger.trigger


Through intelligent engineering, binary triggers now offer a more flexible shooting experience. Depending on the needs of the shooter, semiautomatic mode is available; then one can switch to binary mode for increased capabilities. If you are ready to shoot faster, take a look at our binary trigger options from Franklin Armory and Fostech.

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