Guide to Binary Triggers in Airsoft

While most airsofters are likely familiar with select fire and burst modes and the fun that these can bring to a game, perhaps fewer are familiar with binary triggers.

Somewhat controversial in airsoft, binary triggers have been around for a few years and, love them or hate them, they do serve a purpose and can provide a good deal of flexibility and function to airsoft guns.

If you’re currently wondering about binary triggers and want to learn a little more about them and their potential use on the field, then read on as we dive into this curious airsoft function.

What Is A Binary Trigger In Airsoft?

Inspired by binary triggers in the real steel world, and something that has been around in the paintball world for some time, airsoft binary triggers are a deliberate modification of a gun’s fire selection/trigger function that provides a greater rate of fire.

In effect, a binary trigger function allows an airsoft gun to fire twice with each trigger pull, once when the trigger is pulled and again once it returns to its default position.

Diagram of binary trigger airsoft function

Like burst mode functions, binary triggers generally rely on a programmable MOSFET/Electronic Trigger Unit (ETU), a little computer board that essentially “reads” the trigger and gearbox and issues instructions accordingly.

Unlike burst mode, a binary trigger function can be used when an airsoft gun is set to semi-automatic, and unlike DSGs it doesn’t require much in the way of physical modification to the gearbox.

In many cases it can, of course, also be an option for other fire select modes (such as burst or auto), which allows an airsoft gun to release two streams of BBs with each pull, although due to the massive volley of fire this would produce this tends to be less commonly used in the real world.

What Are The Benefits Of An Airsoft Binary Trigger?

Rate of Fire

The main benefit of a binary trigger in airsoft is to increase a gun’s potential rate of fire.

In particular, it means that users who are restricted to semi only can effectively send more BBs down range than they would normally be able to without doing a ton of gearbox work.

It is also a function that can be especially attractive to those who have guns with heavier or otherwise less responsive triggers and who struggle to keep up with opponents wielding speedier AEGs or HPA rigs. 

In fact, on a good build with a responsive trigger set up (and with a quick trigger-fingered user), a binary trigger build can conceivably have a higher rate of fire than some cheaper full auto airsoft rifles, something that can be an amusing surprise on the field. 

Increased Control Compared To Auto

Although having a double shot does increase the ROF on an airsoft gun, a binary trigger does have another, somewhat more practical, benefit. 

On semi, it gives the user more control over their shots on the field compared to a burst of full auto. 

Binary triggers are a known quantity – users know that with every trigger pull their gun will fire off two BBs and they know with a good degree of certainty when that will happen.

This is in contrast to relying on full automatic fire, which tends to spam BBs downfield with a trigger pull. 

The total quantity can vary depending on a few conditions, but in general the ROF roughly relates to how long a user keeps their trigger depressed.

Increased likelihood to hit a target compared to a single shot 

As a binary trigger fires off a second shot when the trigger returns, users can be more confident that if they miss with the first shot they can get them with the second, which tends to follow up pretty quickly compared to a traditional single shot trigger. 

Relatively easy to add

Binary trigger functions are an increasingly common feature of higher-quality MOSFET/ETU combos now, usually featured alongside other trigger mods such as burst modes, hair trigger, sensitivity adjustment and so on.

As a result, making your gun binary trigger-capable is simply a matter of adding or swapping MOSFETs with a model that has a binary function pre-installed.

close up picture of a gate titan mosfet with binary trigger function set into an airsoft gearbox

Compared to adding a DSG, which often involves shaving or replacing a key gear in an AEG gearbox, replacing or adding a MOSFET is a pretty simple and elementary modification.

What Are Some Of The Potential Downsides?

Binary triggers may be frowned upon or even banned from fields

Many airsoft fields specifically ban binary triggers as they tend to violate rate of fire restrictions, even if the gun is set to semi-auto, and tend to see them as a safety risk as they can increase the risk of accidental discharge incidents. 

Some fields may even ban guns with binary trigger functionality completely (even if they are included stock in a brand new gun) and may ban a user completely for trying to sneak one in.

May cause a little more wear and tear

Binary trigger functions allow an airsoft gun on semi to fire twice per pull. 

Doing so can increase the strain on certain internal components compared to a traditional single shot (or even a burst of automatic), and those who frequently use a binary function may see slightly greater wear on their gun’s cutoff lever, motor, gear lever and more.

Makes it harder to single tap an opponent

While it’s true that a binary trigger can make follow up shots quite easy if you miss, it’s important to consider what will happen if you do hit your opponent with your first shot and they call a hit.

As a binary trigger will fire again when you release the trigger, you’ll have to either hit your opponent again needlessly (which can be considered bad form) or quickly shift your gun off target, which can be a waste of a BB at best and dangerous at worst.

Given that switching off a binary trigger function can take a little fiddling, which may not be so easy to do in game, this is something you’ll have to think about before heading to the field. 

Why Do Some Airsoft Fields (And Other Users) Dislike Binary Triggers?

Player safety and fair play are usually top of mind for most airsoft fields.

As there is often a great disparity between the average casual airsoft player showing up with, say, their first stock G&G Raider that gets an RPS in the teens and a HPA-packing player who can spam 50 RPS with ease, many fields have started adding rate of fire restrictions in addition to FPS limits. 

In particular, many have begun implementing semi-only rules to level the playing field somewhat.

As a binary trigger can allow a gun to remain in semi-auto while allowing users to potentially nearly double their ROF it can be seen as an unfair advantage and a violation of the spirit of the rule, if not the letter.

And if an ETU supports adding a binary function to burst or auto, it can lead to potentially uncontrolled and even dangerous situations on the field.

As a result, many of these fields have started adding specific rules targeting binary trigger users. 

So Where Can I Use One?

All this isn’t to say that if you have a gun that does have a binary function you’ll never be able to use it.

They can still be used in pretty much any field that doesn’t have a semi-only rule or ROF restrictions, of which there are thankfully still quite a few.

They may also be used in casual games and events, with the agreement of other users, and of course at home or with friends. 

Bottom Line: Are They Worth It?

Although not every user or field operator is a fan of them, binary triggers can be a very useful function on an airsoft gun.

Like burst mode and hair trigger, a binary trigger function can provide an airsoft gun with greater flexibility in function.

They are also generally included as an optional function on many better quality MOSFET/ETUs, which means that they can simply be one of many different interesting possible functions that are included in a component that you might be installing anyway to protect your airsoft gun and increase its functionality on the field. 

And since having the option for a function as fun as a binary is generally a lot better than not, we’d say that having the option to set a binary trigger can be very much worth it, especially if you’re looking for a MOSFET install or upgrade anyway.

One thing we would recommend, however, is to make sure that the ETU they are attached to is relatively easy to program/reprogram as your local fields may change their policies without warning, or you may be invited to a new field for an event or skirmish, and the ability to turn a binary trigger function on or off quickly and easily can be somewhat helpful. 

screenshot of airsoft etu app showing binary trigger option

Some Notable MOSFET/ETUs with Binary Trigger Functions To Check Out

As we’ve mentioned, binary trigger functions are included on many higher MOSFET/ETUs along with other trigger mod functions.

Some models we like can be found below.


One of the best known and reputable companies making MOSFETs and ETUs in airsoft, GATE offers a number of ETUs with binary trigger options at a number of different price points. 

These include their flagship model, the GATE TITAN and their more affordable ASTER. 

Both ETUs can be programmed through a pretty slick and visual app interface, the GATE Control Station, which connects to the ETU via USB or Bluetooth and allows users to make a wide variety of adjustments to their build with very little effort or confusion.

screenshot of gate control center app for airsoft etu

Check out GATE products on Airsoft Station

Jefftron Leviathan

The Jefftron Leviathan is a  programmable ETU that includes a microswitch, CNC trigger, as well as binary trigger mode. 

Although not exactly cheap, the Leviathan is well-built, relatively easy to install and offers users a ton of potential functions aside from binary, including fire selection, fully adjustable burst mode, low battery warning, pre-cocking, and much more. 

Check out the Leviathan on Evike


Perun is known for making high-quality, compact and reliable MOSFET/ETUs for a wide variety of gearboxes and airsoft guns, including those specifically designed to easily fit V2 and V3 gearboxes, P90s, Steyr AUGs, Kriss Vectors and more. 

Most of their product offerings offer binary trigger functions and tend to be pretty affordable on the whole, particularly given their quality and reputation. 

Check out Perun options on Evike

Will Martin – Will has been into airsoft and paintball for well over 10 years, and has done it all – from upgrading and fixing gearboxes as a tech to building custom airsoft loadouts for his friends to supporting off those friends as a DM.