How To Silence an Airsoft Gun (9 Simple Ways)

Fact: Airsoft guns can go as loud as 95-100 decibels, similar to what a power lawnmower makes. This is why many owners are looking for ways to make their automatic electric guns (AEG) quieter.

Here’s how you can silence your airsoft gun in 9 simple ways:

  1. Insert a wrapped coil into an empty suppressor.
  2. Shim your airsoft gun gearbox.
  3. Use thick gear lubricant.
  4. Make sure that the airgun is sealed well.
  5. Weaken the spring. 
  6. Go for a tighter bore size. 
  7. Use a high-speed ratio gear. 
  8. Drill holes in your piston.
  9. Use a Sorbo pad. 

If you own an airsoft gun and have been looking for a way to silence it, then you’re in the right place. We’ll go over a list of things you can do to make your guns quieter. Let’s get started!

1. Insert a Wrapped Coil Into an Empty Suppressor

If you have a TDS or HV airsoft gun, then this is something you ought to try. It’s easy to do, plus all you need are three things:

  • Foam strip
  • Coil spring
  • Mock suppressor 

Start by rolling the foam strip around the coil spring. Put it inside the buffer, and you’re done!

It’s important to note, however, that foam suppressors are technically illegal in most US states. That’s because they’re good enough to silence REAL guns. 

That said, some states allow such use. You’ll need to pay for a permit and wait for a few months, but you can go ahead and use it. 

So, unless you’re willing to break the law – or live outside the US – you may want to try the other methods here instead. 

Video: How to make your airsoft gun silent

2. Shim Your Airsoft Gun Gearbox

In AEGs, the part that makes the most sound is the gearbox. This mechanical system features motors and gears that transfer electrical to mechanical energy. In other words, it fires your gun.

That said, one of the best ways to silence your gun is to shim the gearbox. 

This process helps optimize the area between the gears and helps limit the space it needs to run seamlessly. 

There are two ways for you to shim your gun. One is the bevel gear method, which I’ll be discussing below.

To do this, you need to:

  1. Take the gears apart. Once you have them in individual pieces, clean every one of them. 
  2. Move the pinion gear. Do this in a way that it comes into contact with the bevel gear. 
  3. Move the bevel gear next. Make sure that it matches with the pinion gear. 
  4. Remove the motor and pistol grip. This will prevent them from getting in the way every time you open and close the gearbox shell. 
  5. Put some screws in the shell. Tighten them with screws. 
  6. Add shims to the bevel gear. You know you’ve added the right amount if the gear spins freely. If it doesn’t slide up and down when the gearbox is closed, then you’re good to go. 
  7. Add shims to the spur gear. You should place these spacers under the flat part of the gear. 
  8. Add shims to the bottom of the spur gear. If you can make two complete rotations with this, you’ve shimmed it up quite well. 
  9. Close the gearbox. Now, you have a ‘quieter’ AEG! 

Tip: If you find it hard to follow the steps above, it’s best to bring your AEG to an airsoft technician instead. 

Benefits of Shimming Your Gun

Shimming, when done correctly, can do more than quiet your gun. It can also offer the following:

  • Gear protection. Shimming helps lessen the friction and straining in the gear parts. As a result, they’re less likely to break or snap. 
  • Improved gearbox life. Shimming prevents unnecessary friction in between gears, thus leading to lesser stress levels on the said parts. While shimming is excellent for your gearbox, it serves your motor the best. It helps transfer the energy more efficiently, thus lessening the chances of motor damage. 
  • Better fire rate. Shimming prevents friction and the energy loss that comes with it. Instead, it’s transferred to your gun, which means you can enjoy an enhanced fire rate. 
  • Longer battery life. Whenever the gun strains, it uses more battery power. Since shimming prevents friction and straining, your AEG won’t take up as much juice. Now, you have a far longer shooting time to enjoy! 

What Happens if You Fail to Shim Your Gun Properly

Shimming should be done with extreme care. This is especially the case if you’re a beginner, given that there are many things you need to do.

If not done properly, your gun may suffer from these consequences:

  • Louder sound. Shimming your gun can make it quieter. But if done the wrong way, it can make it sound louder. That’s because bad shimming can cause the gears to rub with each other more than they should. 
  • Weaker performance. If shimmed incorrectly, your gun won’t be as efficient as it used to be. The friction or incorrectly-placed gears may lead to a slower feet-per-second (FPS) performance.
  • Damaged gear teeth. If you’re not careful, you can end up misaligning the gear teeth. This will strain the parts and eventually break them. 
  • Broken motor. Incorrect shimming will cause the motor to work harder. In the long run, it’ll break down and stop working. 

3. Use Thick Gear Lubricant

Lubricating your gearbox regularly will help improve your AEG’s lifespan. It can help reduce friction that can lead to heating and other damages. 

Add to that, lesser friction means quieter airsoft gun sounds. 

When it comes to lubricating gears, make sure to use the extra-thick kind. It stays on for longer, so it’s more effective in reducing friction – and the sound it makes. 

Here are some tips to follow when lubricating your gearbox:

  • Only lubricate the parts that are moving. There’s no need for you to waste lube on non-moving items.
  • Grease the lowest gear axle and teeth and the sector gear. If you’ve lubed the gears properly, you should see a swirl pattern in between the lower and sector gears.
  • Apply grease on bevel gear teeth as well. 
  • Lubricate the pinion gear teeth if you want.
  • Make sure to lubricate the nozzle if it’s loose or if there’s an air leak in it.

4. Make Sure That the Airgun Is Sealed Well

As the name suggests, AEGs make use of air to shoot. If there are leaks, it won’t shoot as strong as it should. 

Air sealing does more than improving your gun’s muzzle velocity, though. It’s a way for you to silence it as well. 

With a tighter seal, you can replace your current spring with a weaker one. This part is responsible for the metallic twang you hear after firing the gun. 

A loud sound occurs every time the receiver is fired. That’s because the spring causes the gearbox to resonate. 

As such, air sealing your gun allows you to use a weaker spring that makes quieter sounds. 

As for the performance of your AEG, there’s no need to worry. 

Sealing the gun will prevent the air from escaping. Because there’s no wasted air, a weaker spring will work just as well as the stronger one.

Video: The Most Silent Airsoft Gun Ever

AEG Areas To Seal

Before you replace the spring, you need to check and seal these AEG parts first.

Cylinder and Head

Most AEGs have an adequately sealed space between the cylinder and cylinder head. But if you want to be 100% sure, you should try to put your finger on the end of the piston. 

Submerge the piston underwater and slide a finger in to put pressure. If you see bubbles around the edge, then the head isn’t sealed well. 

Should this happen, you can use Teflon tape or RTV silicone to seal the area. 

It’s also good to keep the area between the piston and cylinder sealed. You can do so by placing a #14 O-ring expansion around the area. 

Head and Nozzle

You can check the sealing by putting the air nozzle and firing it close to your finger. You can also use your mouth to blow into the cylinder or put pressure on the piston instead. 

When you do this, there should be no air coming out. If there is, you’ll need to place an air seal nozzle on the area. 

How To Change Your AEG Spring

Here’s a tutorial on how to change your AEG spring for a quieter performance:

  1. Disassemble the gearbox. Do so carefully to avoid the parts from spring out. 
  2. Lift the spring guide. This should help you loosen and remove the spring quickly. 
  3. Remove the old spring. Replace it with a new, weaker one. For example, if your gun has 395-405 FPS, you may go for a spring with 340-360 FPS. You can find the details on different springs here
  4. Reassemble your gearbox carefully. 

5. Weaken the Spring

As mentioned above, your spring’s performance can make your AEG noisier. So apart from downgrading your spring, you can make it quieter by weakening it.

Here are several ways for you to do so:

Compress the Spring

The spring compresses and gradually weakens with regular use. This is what airsoft aficionados call ‘settling down’ or ‘breaking in.’

You can achieve the same effect by keeping the spring compressed or half-fired overnight.

To do so, you need to fire your gun twice in semi-fire before you put it away. 

Make sure to pull on the trigger in a way that compresses the spring without releasing it. You should hear the motor pull the spring out when you do so. 

By compressing your spring, you can reduce the FPS by 20 to 80. The result: a quieter gun! 

Cut the Spring

Use a hacksaw or metal-cutting wheel Dremel to cut the springs. Just be careful because you don’t want the coil flying to your face!

Remember, removing 1-2 coils is enough to decrease the FPS by 20-30. 

Work With Heat Shrink Tubing

Buy three heat-shrink bits measuring at least 10 mm (0.39 in) each. You can easily get this from your neighborhood hardware store.

When doing this, make sure to attach one bit for every third of the spring. This will muffle the vibrations, thus lessening the twang sounds. 

6. Go for a Tighter Bore Size

The tighter the bore is, the higher FPS you’ll produce. 

This technique is similar to the air sealing scenario. Because you have a high FPS at hand, you can trade your current spring for a weaker one. 

You can even compress or cut it, as mentioned above. 

As mentioned, a compressed spring will deliver less stress to the gearbox. As a result, your gun will make a ‘quieter’ squelching sound. 

For best results, go for a bore size ranging from 6.01 to 6.03 mm (0.23 to 0.23 in) . Just make sure to clean it regularly to prevent it from jamming! 

7. Use a High-Speed Ratio Gear

The gear ratio refers to the number of times a bevel needs to spin to complete a cycle. The higher this is, the better your rates of fire. 

Apart from this benefit, a high-speed ratio gear (at least 14:1) is known to produce a faster sound. Of course, the faster the sound is, the less you’ll hear of it. 

High-gear ratios also have a lesser tendency to produce a squelching noise. With these features, this item is sure to give you a quieter shooting experience. 

8. Drill Holes in Your Piston

A lighter piston allows the sector gear to pull back easier, thus leading to faster forward-firing.

Not only will this result in a higher FPS and a quicker cycle, but it can reduce the squelching sounds as well.

To lighten your piston, you can drill it through a process called Swiss cheesing. The tools you need for this are:

  • Dremel Drill 
  • Vice Grip
  • Goggles 
  • Respirator

The steps for Swiss cheesing are as follows:

  1. Put the piston in the vice grip. Don’t clamp on it too hard, or else you will deform it. 
  2. Drill holes in an organized pattern, layer by layer. Make sure that the holes are spaced evenly. Don’t drill too close to the piston rear!
Video: Different upgrade pistons for airsoft AEG

9. Use a Sorbo Pad

Also known as a Sorbothane cylinder head dampener, it can prevent gearbox shell cracking and also help correct the angle of engagement. 

Another good thing about a Sorbo pad is that it can effectively reduce piston stroke noise. This sound is produced when the piston rocks back and forth in the cylinder. 

Because of the pad’s ability to absorb shock, you won’t hear as much noise when you fire your AEG. 

Final Thoughts

There are many ways to silence your airsoft gun. By following the tips above, you don’t have to deal with a lawnmower-sounding AEG from now on.