A Beginner’s Guide to DSG Airsoft Guns

If you’re prone to cruising airsoft forums in your spare time, chances are you’ve probably come across a thread (or dozen) discussing DSG airsoft builds. 

With videos of DSG builds demonstrating sky-high rates of fire on the field, they often capture the attention and interest of players looking to take the next step in their airsoft journey.

Unfortunately, DSG builds can also be quite a challenging project to take on for the average airsoft player.

If you’re curious about DSG airsoft guns and wonder if it might be worth your time and  money to modify your existing AEG, then read on as we explore this high-firing build. 

What is a DSG Airsoft Gun?

A DSG (Dual Sector Gear) airsoft gun is an AEG airsoft gun of some kind whose gearbox has been modified to replace the sector gear with one that sports teeth on both sides of the gear.

picture showing dsg airsoft gear

These builds stand in contrast to typical airsoft gearboxes that use what are called single sector gears, which only contain a strip of teeth on one half of its body, such as seen in the image below. 

picture showing a single sector gear in an airsoft gearbox

Very basically, single sector gears typically can only fire one BB per gear cycle (turn), while DSGs, which have two sets of teeth (that is, a strip of teeth on each half of its body), can fire two BBs per gear cycle, in effect doubling the gun’s rate of fire. 

In theory, an airsoft rifle delivering a stock 25 RPS might see 50+ RPS if converted to a DSG setup. 

It is important to note that DSG airsoft guns are a custom build and, for reasons we will explore later, aren’t readily sold by airsoft manufacturers. 

How They Work

A DSG gear typically has fewer teeth on each side of its body compared to a single sector gear, which means it draws the piston back only about half way before releasing it. 

For example, if a typical single sector gear has a row of 16 teeth, a dual sector gear might have 8 teeth on one side and another 8 on the opposite side. 

Because it sports a second pair of teeth on the opposite side of the gear, it then repeats this action a lot faster than a single sector gear, which would have to complete a full rotation before engaging the piston again.

What this means is that a DSG setup will give an airsoft gun a much faster cycle rate, with the piston being drawn back more frequently and having to travel a shorter distance overall.  

This cycle rate can be seen in the animation below.

Compare this to an animation showing a traditional gearbox with a single section gear and the difference becomes very noticeable.

In other words, we can say that DSG builds essentially work by short stroking an AEG airsoft gun’s piston and doubling the piston strokes per cycle with the second pair of teeth.

This is where they tend to differ from most other short stroke builds, which tend to focus on removing teeth from a single sector gear and only have one action per cycle. 

If you guessed that all this might have some kind of negative effect on an airsoft gun’s performance, you’d be right. 

Drawing the piston back only partially can increase RPS/RPM, but will also ultimately lower compression, leading to a loss of power (among other issues ) unless a variety of rather extensive modifications are made to the system. 

Why don’t all AEG gearboxes come with Dual Sector Gears?

Because they engage and release a piston more frequently, DSGs typically tend to put more strain and stress on an airsoft gearbox than a single sector gear might otherwise. 

As a result, a DSG setup can reduce the lifespan of a gearbox’s stock component parts, which effectively reduces the airsoft gun’s lifespan altogether for most users (if it doesn’t suffer catastrophic failure from the start, that is). 

While the promise of doubling a gun’s RPS is an attractive one, airsoft gun manufacturers always need to balance performance with reliability or they won’t be in business very long. 

While a factory could, in theory, build airsoft guns to handle the increased rate of fire of a DSG gear setup, the use of reinforced components, altered gearing, shorter barrels and more would dramatically increase the costs (and retail price) of what is effectively a niche product. 

Why Are DSG Airsoft Guns Considered Hard to Build?

If you’ve visited an airsoft forum in recent years you might have seen various users warning others not to attempt a DSG build until they’ve had some experience at custom airsoft builds. 

Unlike most other arguments in airsoft forums and communities, this isn’t just something that veteran players say to troll or gatekeep new airsofters. 

Building a DSG airsoft gun is actually something that requires a fair bit of technical expertise and the potential for it going catastrophically wrong makes it something that is generally recommended as a project for beginners or even seasoned airsofters. 

This is because DSG builds require opening and messing around with the gearing of an AEG to a significant extent, replacing a key gear with a one that the manufacturers never really intended to be installed. 

Much like an expensive mechanical watch, messing around with one part can have a knock on effect on all the others, meaning the whole system has to be retuned, reconfigured and properly balanced with appropriate parts for the whole thing to work properly. 

And this is, of course, assuming that the model of airsoft AEG you’ve chosen as a base is easy to work on and readily accepts upgraded parts and modifications.

While we won’t dive into the specifics of a build in this article, just to give you an idea of some of the things that might be involved in a DSG build, we’ve outlined just some of the things that need to be considered if you’re starting from a stock, out of the box AEG.

For one thing, a sector gear doesn’t act alone. 

A DSG build will also need to make sure the pinion, bevel and spur gears mesh and can work without ripping apart or breaking, so users have to make sure there’s no soft metal being used in the wrong area. 

Obviously, the piston will have to be looked at, as well, and probably replaced with one that has a durable, full metal rack to prevent stripping (or worse). 

They will also usually require the removal of some teeth and shimming to adjust the angle of engagement. 

Similarly the tappet plates and fin will need to be modified to compensate for the shorter cycle time and prevent feed and loading issues. 

And, of course, users will need a stronger spring than can usually be found on stock airsoft AEGs to compensate for the shorter stroke distance. 

The bearings or bushings, too, will likely have to be replaced with higher quality parts that can handle the increased performance. 

A DSG build will also need a compatible motor with appropriate torque, ideally replacing them with some kind of neodymium or other strong magnet.

If the gun comes with a MOSFET, chances are it will also need to be replaced with one that can handle a DSG build without burning out.

Same with fuses, which are prone to popping with higher torque aftermarket motors. 

Finally, short stroking an AEG means that there will be less air volume in the inner barrel, meaning that users often need to compensate by installing a shorter barrel and making sure they match the cylinder to barrel volume for a given BB weight. 

This, of course, tends to be just the start. 

There is a veritable laundry list of parts that might need to be replaced or modified as the DSG build progresses and a user begins to test its performance, such as nozzles, springs, hop ups and on and on and on. 

And all this is the mechanics of an initial build. 

Users also need to factor in the added weight and inertia that reinforced parts can add to an airsoft gun, and they need to consider what will happen if something breaks and the extra cost and difficulty finding a replacement part. 

Finally, since it is a custom build with different performance characteristics and aftermarket parts all working together, users will probably want to do more periodic maintenance to check that things are holding up as they should. 

Do DSG Builds Help with FPS


DSG builds are meant to improve the rate of fire of an AEG airsoft gun, not its power. 

In fact, without compensating for the shorter piston cycle and air volume, a DSG build can actually dramatically lower FPS. 

Do I Really Need A DSG Airsoft Gun?

Most airsoft players don’t need an dual sector gear airsoft build and probably wouldn’t see much benefit to one in-game. 

To be honest, these days there are a lot of different ways to bump up an AEG’s rate of fire that don’t require an overhaul of its mechanicals. 

Many aftermarket MOSFETs these days come with cycle detection, pre-cocking and other functions that can speed up an airsoft gun’s trigger response quite a bit even on standard gears and ratios. 

Add to that the fact that there are currently a variety of higher-voltage batteries, ETUs and motors on the market, as well as plenty of aftermarket gearboxes with better gearing, all of which can help ROF and are a lot easier to install and maintain than a full DSG build. 

In fact, with today’s technology and aftermarket accessories, it’s not uncommon for users to get excellent rates of fire, 40+ rps in some instances, while still using a single sector gear setup. 

Now, to be sure, this isn’t to say that DSG airsoft guns are a relic of some bygone past. 

Properly configured, they can get a truly insane rate of fire, well over 60 + RPS if done right, and are an excellent exercise in technical skill for those so inclined and who have the time and money to do so. 

Summary Table: DSG Airsoft Guns Pros and Cons

DSG Airsoft Build AdvantagesDSG Airsoft Build Disadvantages
Capable of extremely high rate of fireTakes some skill and knowledge to get right and avoid performance issues
Vastly improved trigger responseCan be expensive – requires a lot of replacement and tuning of other parts
Fun skill challenge for tinkerers and technically inclined airsoftersIncreased stress and strain on parts
Harder and more expensive to maintain in the long run

Bottom Line

Dual Sector Gear builds are a commonly discussed topic on airsoft forums. 

DSG airsoft guns can have their advantages, namely in rate of fire, but their relative difficulty and cost of construction, the increased maintenance they require, and the availability of easier to install aftermarket performance parts, means that beginner and intermediate airsoft players might want to think twice before popping open their gearbox. 

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.