Do you hate loud and screechy AEGs? Maybe it’s time to shim your gearbox! 😄

Shimming your gearbox is one of the most important maintenance tasks for your replica. A well-shimmed gearbox runs smoother, quieter, and lasts longer.

For beginners, shimming can feel intimidating, but with patience and the right approach, it’s completely doable.

In this guide, we’ll walk you through step by step how to shim your gearbox, starting from the bevel gear, and what you’ll need.

Tools & Materials

• A disassembled gearbox
   
• Shims (1 set is usually enough for one replica)
   
• Screwdriver or hex set (depending on your gearbox screws)
   
• Isopropyl alcohol + cloths
   
• AEG gear grease
   

Preparation

For disassembling your gearbox and removing the piston, cylinder, and small parts, there’s plenty of information on YouTube. This varies per brand and type of AEG.

Tip: search for

“[Your brand] AEG gearbox disassembly” – The Tube is your friend. 😉

After disassembly, clean the gears and gearbox shells thoroughly with isopropyl alcohol and a cloth, removing all grease and dirt.

Preparation

For disassembling your gearbox and removing the piston, cylinder, and small parts, there’s plenty of information on YouTube. This varies per brand and type of AEG.

Tip: search for

“[Your brand] AEG gearbox disassembly” – The Tube is your friend. 😉

After disassembly, clean the gears and gearbox shells thoroughly with isopropyl alcohol and a cloth, removing all grease and dirt.

Step 1: Bevel Gear (The Heart of Your Gearbox)

The bevel gear has direct contact with the motor, so the height alignment with the motor pinion is crucial.

How to start:

1. Begin with 1 shim under the bevel gear.
    
   • Preferably a slightly thicker shim as a starting point.
      
2. Place the bevel gear in the lower shell of the gearbox.
    
3. Slide the motor/pinion in place (see photo) and check the height.
    

What to watch for:

• The bevel gear must contact the motor pinion properly.
   
• Too low → the gear shaft tilts.
   
• Too high → poor contact, noise, and extra wear.
   

Goal: the bevel gear spins smoothly, straight, and engages correctly with the motor pinion.

Step 2: Spur & Sector Gears (Bottom Shim)

Once the bevel gear is aligned, we adjust the bottom of the spur and sector gears.

Objective:

• Gears must not scrape the shell
   
• Gears must engage correctly with each other
   
• Gears must not sit too high
   

How to do it:

• Place the spur and sector gears in the lower shell
   
• Shim the bottom until they sit freely without rubbing
   
• Check by rotating them by hand
   

Tip: adjust one gear at a time to avoid confusion.

Step 3: Top Shim (Finishing Touch)

Next, adjust the top of the gears relative to the upper shell.

Steps:

1. Place the upper shell without top shims.
    
2. Use three screws (for V2 gearboxes) to apply even pressure on the gears.
    

Measure clearance:

Add shims:

• Unscrew the shell
   
• Place top shims of the appropriate thickness
   
• Repeat until there is a tiny bit of play
   

Guideline: about 0.1 mm play. Gears must spin freely but not wobble.

Tip: start with thin shims and take your time!

Spin Check

Once all gears are shimmed, do a spin check:

• Rotate the gears via the cylinder opening
   
• They should spin freely and smoothly without scraping

  Step 4: Lubricate the Gears

  Apply a small amount of AEG gear grease to all gear teeth:

• Too much grease → extra friction
   
• A thin layer → less wear, quieter gearbox

• Step 5: Reassemble the Gearbox

  Reinstall all parts:

• Piston + piston head
   
• Cylinder + cylinder head
   
• Nozzle / tappet plate
   
• Trigger parts
•  
• Spring + spring guide
   

• Check while tightening screws that the gears still spin smoothly.

  Step 6: Test Your AEG

• Reinstall the gearbox in your AEG
   
• Test on semi-auto
   
• Listen for noise and check smoothness
   

• A well-shimmed gearbox is immediately noticeable:

• Quieter
   
• Less rattling
   
• Smoother and tighter operation

Done! 🎉

✅ Congratulations! Your AEG is now shimmed starting from the bevel gear, ready for a smoother, quieter shooting experience.

Airsoft is a versatile sport, and when starting out, you have many choices in replica types. But which system suits you and your playstyle?
In this blog, we explain the differences between AEG, GAS, CO₂, and Spring replicas.

What type of player are you?

Before diving into the technical details, think about how you play.

• Beginner / casual skirmisher: you want a reliable, easy-to-use replica.
• All-round: you play strategically on all types of fields: CQB, open fields, Milsims.
• CQB (Close Quarters Battle): fast, compact guns with good handling.
• Milsimer: realistic replication, accuracy, and upgrade potential are important.

The technology:

AEG:
AEGs, or Automatic Electric Guns, are the most popular choice for both beginners and experienced players. They are reliable, easy to maintain, and perform well in all weather conditions. Upgrade options are plentiful, from simple pressurization upgrades (Hop-Up) to a full HPA (High Pressure Air) conversion.

Advantages:

• Consistent performance
• Magazine capacity
• Easy maintenance
• Many models and upgrades

Disadvantages:

• Slightly less “realistic”
• Motor noise

Gas replicas:
Gas replicas use green gas, propane, or other gases to fire BBs. They replicate the recoil realistically and are often the choice for advanced players or those who value realism.

Advantages:

• Realistic feel and recoil
• Fast semi-auto response

Disadvantages:

• Less consistent in cold weather
• Requires maintenance and gas refills
• Magazine capacity
• Higher running costs

CO₂ replicas:
CO₂ replicas use small cartridges (12g) that are stable in various temperatures. Often, revolvers and NBB (Non-Blowback) replicas are CO₂-powered, and some gas replicas can also use CO₂ magazines (often referred to as “Dual Powered”).

Advantages:

• Less temperature-sensitive than gas
• Strong, consistent shots

Disadvantages:

• CO₂ can be more expensive
• Some models have stronger recoil
• Often higher FPS / Joule

Spring replicas:
Spring replicas are powered by a manually cocked spring. This system is most popular for bolt-action snipers and pump shotguns.

Advantages:

• Simple to use
• Higher FPS / Joule
• More precise shot pattern (snipers)

Disadvantages:

• Cocking the spring requires physical effort
• Less variety

Conclusion and advice

Airsoft offers a suitable replica type for every playstyle. The best choice depends on your experience, playstyle, and personal preferences.

• Beginners or casual players are best off starting with an AEG, reliable and easy to use.

• Players who value realism and recoil may choose gas replicas, ideal for semi-auto shooting and realistic gameplay.

• Those looking for consistent performance in different temperatures or powerful shots should consider a CO₂ replica.

• Bolt-action snipers and pump shotgun enthusiasts benefit most from spring replicas, simple, powerful, and precise.

Advice:
Think carefully about how you play and what matters most to you: reliability, realism, power, or precision. Choose a system that fits your playstyle and consider maintenance, running costs, and upgrade options. This way, you’ll get the most out of your airsoft experience.

What is a red dot?

A red dot is an optic that projects or reflects an aiming point onto a lens, without any zoom (1x).

There are two main types:

• Reflex sights
• Holographic (Holo) sights

Reflex vs Holo

The difference lies in how the aiming point is displayed.

Reflex sight

A reflex sight uses LED diodes that reflect the aiming point through a lens to your eye. Simple, effective, and usually affordable.

In airsoft, almost all red dots are reflex sights, even if some look like a holographic sight (think “EOTech lookalikes”).

Advantages:

• Cheap
• Lightweight
• Long battery life
• Many shapes and sizes
• Compact and easy to mount

Disadvantages:

• Aiming point can distort with astigmatism
• Sometimes hard to see in bright sunlight (cheaper models)
• Lens may have reflections or color shifts
• Aiming point “floats” on the glass

Holographic (Holo) sight

A holo sight uses a laser to project a hologram of the aiming point onto the lens. More complex system and more expensive, but very accurate.

Advantages:

• Sharp aiming point, even with astigmatism
• Aiming point remains visible even if the lens is damaged
• Fast target acquisition
• Almost no parallax errors

Disadvantages:

• Expensive
• Shorter battery life
• Larger and heavier
• In airsoft, realistic only on high-end replicas

What is parallax?

Parallax is the phenomenon where the aiming point appears to shift if your eye is not exactly in the center of the lens.

A good red dot or holo sight has almost no parallax, so the aiming point stays where it should.

In short: the aiming point doesn’t “jump around” when you look from a different angle.

Real Steel

A red dot labeled “real steel” means it is suitable for actual firearms and can handle recoil.

Do you need that for airsoft?
Not necessarily, but real steel dots are often:

• More robust
• Higher-quality glass and mechanism
• Longer warranty

For airsoft, this is a nice bonus, but not required.

Conclusion

Reflex sights are the most popular and affordable option for airsoft.

Holo sights are more precise and cooler, but more expensive and usually only interesting for high-end replicas.

Pay attention to parallax and whether the optic is durable or real steel-compatible.

In short: for most airsoft players, a good reflex sight is perfectly fine, but those who train seriously or want the real steel experience can consider a holo or real steel-style sight.

Introduction

From the need for a compact rifle for US SOCOM (United States Special Operations Command) and US SOF (United States Special Operations Forces), the Close Quarters Battle Receiver (CQBR) program was born. Lessons learned during the Vietnam War, combined with the changing demands of the Cold War and modern conflicts, showed that operators needed a shorter, more adaptable weapon system than the standard M16 and M4.

This led first to the CQBR M4A1 and later to the now legendary MK18.
The MK18 is not simply a short‑barrel rifle; it is a complete weapons platform. It combines modular rails, mission‑specific accessories, optics, and laser aiming devices, optimized for suppressor use and close‑ to medium‑range engagements. Favored by elite units such as the Navy SEALs and Delta Force, the MK18 has earned its reputation as a feared and respected rifle on the battlefield.

The MK18 in Airsoft

In airsoft, the MK18 offers far more than just “cool factor.” Its modular design makes it one of the easiest platforms to customize and personalize. With excellent ergonomics and endless accessory options, the MK18 suits everyone—from beginner players to hardcore, experienced operators.

No two MK18 replicas are the same on the airsoft field, and that individuality is a big part of its appeal.

 

Things to Look Out For

Despite having plenty of rail space, many beginner MK18 setups quickly become overloaded with accessories. More gear does not automatically mean better performance. For optimal effectiveness, it’s best to follow the K.I.S.S. principle (Keep It Simple, Stupid).

Always consider the environment you are playing in:

• On a CQB field, a magnifier is usually unnecessary.

• On an outdoor field during daytime, a tracer unit may only add extra weight.

Build your setup around function, not appearance.

Must‑Have Accessories

Red Dot Optic

At a minimum, a red dot sight is one of the best upgrades for any airsoft replica. When properly zeroed, it allows for faster target acquisition and improved accuracy.

When choosing a red dot:

• Buy the best quality your budget allows

• Clear glass and long battery life are essential

• Consider warranty and durability

Cheap airsoft optics may look good but often perform poorly—especially in bright sunlight—and tend to break quickly. If possible, choose a real‑steel optic designed for firearms. These offer better clarity, reliability, and easier alignment when adding a magnifier.

Grip or Hand Stop

Your grip choice should match:

• Your hand size

• Your shooting stance

• Your preferred holding style

It should improve control without taking up excessive rail space or interfering with other accessories.

Flashlight and Tracer Unit

For CQB gameplay, a flashlight is almost mandatory. Combined with a tracer unit, it makes target identification and BB tracking much easier. Carefully consider placement for easy activation and keep overall replica length in mind.

Conclusion

Whether you’re building a clone setup of a famous SEAL unit or simply want to dominate on the airsoft field, a well‑configured MK18 is extremely effective. With the right balance of accessories and a focus on practicality, the MK18 is truly OP in airsoft.


Photo Source: https://clonerifles.com/