AEG Internal Parts

About the internal parts inside an airsoft Gearbox

Automatic electric guns are airsoft guns that use a motorized system to fire each shot. A high quality airsoft gun will feature a metal gearbox, also known as a mechbox. This is where all the internal parts responsible for the function of the gun resides. In an AEG, these parts are made to be serviced and replaced when necessary. If you possess enough technical ability and knowledge, you can even upgrade these parts to increase performance or longevity. From the factory, the components inside the mechbox are matched together so that the airsoft gun can perform within specifications. Should you upgrade your own airsoft gun, changing one part may adversely affect another so it is important to understand what each component does before you go about doing that.

To break down what the components do, let us first explain how an AEG works. When the trigger is pulled, an internal switch assembly from within the gun opens a circuit from the battery to the motor. The battery powers this motor which will turn a series of gears inside the mechbox. The gears interact with each other and transfer that torque to pull back and cock a piston. Once the gears have made a revolution the gear that interacts directly with the piston will cause the piston to release. A spring behind the piston body will drive the piston forward. When the The piston then travels down the cylinder and that bit of compressed air exits the gearbox and pushes the BB.

Problems in airsoft gun gearboxes as well as areas that can improved are: compression, electrical, and mechanical. If you want to manipulate or tune your velocity, the parts of the systems you would want to change out are the compression parts. Those parts are the piston body, piston head, cylinder, cylinder head, spring, and spring guide. The parts regarding the mechanical aspects of the mechbox which are responsible for giving you your fire modes and activating the motor when the trigger is pulled are the gears, tappet plate, switch assembly, cutoff lever, selector plate. Lastly, the electrical system is what delivers power to your motor so that would be the plug, wires, motor, and sometimes the fuse or MOSFET if your AEG comes equipped with one.

Common upgrade requests we get will be in regards to range and accuracy as well as rate of fire. We offer tech services to help install these parts in many airsoft guns.

Q & A: 

Q: How do I increase my range and accuracy?
A: Range comes as a byproduct of having a higher velocity. Adding extra power could make your gun shoot farther, though if the gun is inherently inaccurate we would always address accuracy too. Accuracy would be more from the barrel, hopup, and bucking you have more than anything, and would not be part of the mechbox.

Q: How do I increase my rate of fire?
A: The rate of fire can be augmented in numerous ways. The first steps that you can take do not require you to open up the gun or change anything critical. The first ways you can see some changes in this department is to upgrade the motor and the battery you are using. This wakes up the gun substantially and is good enough for most people. Depending on the design of your AEG, a motor swap might be really simple too.

Q: How do I increase trigger response?
A: Upgrading the electrical systems to reduce resistance in your system and perhaps changing your gearing will make a night and day difference. This requires major gearbox teardown and time invested in tuning.