In the previous post, we finally decided on the specifications for the gearbox.
This time, we'll install the gearbox, whose specifications have been finalized, into the receiver and assemble the hop-up system.
*This article aims to provide educational explanations from a mechanical engineering perspective regarding the safe hobby use of airsoft guns.
This does not promote acts of violence, the use of weapons, weapon modification, practical evaluation, or violation of laws and regulations.
Lower receiver assembly
I'll finish the gearbox.
One important point to note about overseas-made gearbox ver2 is that it has a simulated bolt stop function, so be sure to install it properly.
We'll be reassembling it in the reverse order of disassembly, as previously explained, but there are a few tricks to it, so I'll explain them in detail.
Insert the gearbox into the lower receiver.
Next, attach the grip and motor.
Push in the floating rear pin.
Next, install the magazine catch. Insert the magazine catch, then install the spring and the magazine release button.
Press the mag release button while tightening the magazine catch.
Next, we'll assemble the slightly complicated pseudo-bolt release mechanism.
Here's a little trick: First, press down on the part attached to the gearbox.
While holding this down, assemble the bolt release lever and hook the tip of the bolt release lever's bar onto a component of the gearbox.
Next, insert the retaining clip into the bolt release lever.
Finally, drive in the pins to finish. Please note that the pins have a specific orientation.
Next, we'll assemble the buffer tube.
Route the wiring as shown in the picture and place the swivel on top.
Next, temporarily assemble the buffer tube and loosen the ring at the base.
Next, use a long Phillips screwdriver to tighten the bolt at the back of the buffer tube.
This step is quite difficult, so a sturdy Phillips head screwdriver will come in handy.
Vessel long driver
You can choose the length on the Amazon product page. 300mm is recommended.
We'll conclude it like this.
Finally, tighten the ring at the base of the buffer tube, and you're done.
Multi-tool for M4 series
It's a no-name brand and quite bulky, but I highly recommend it because of its durability and ease of use.
This completes the lower receiver.
Next, we'll assemble the hop chamber.
Hop chamber assembly
I'm using a high-end hop-up chamber, specifically the MAXX HOP chamber, which offers excellent performance.
Details about this chamber are available here.
Before assembling the chamber, we'll modify the inner barrel. We'll use the original barrel, but we'll slightly modify the shape of the hop-up window.
First, the original hop-up window.
It's a standard hop window, but I modify it to make it smoother so that the hops descend more easily.
Processed products.
Use a rotary tool to smooth out the edges.
Dremel High-Speed Rotary 4000
This is my go-to rotary tool that I always use. Having this expands the possibilities of your DIY projects. There are two popular models, the 3000 and the 4000, but I recommend the 4000 because it comes with a set of tools and has more power.
If you're interested in processing, please refer to the information I've previously shared.
Next, we'll install the Maple Leaf hop packing that was originally attached to this product.
First, apply Tokyo Marui high-viscosity grease to the barrel, avoiding the hop-up window.
Next, carefully install the hop packing, and you're done.
Next, let's look at the hop chamber.
The included hop-up button has a nice curved shape, so I'll use that as is.
The hop-up seemed to be pressed down a little too little, so I adjusted it by attaching a piece of heat-shrink tubing to the lever with adhesive.
Sorry the photo is blurry.
This is completed.
Assemble the barrel according to the instructions and check the hop-up adjustment.
Hop MAX.
It's coming down in a nice, straight line, so it's okay.
Next, we'll install it into the upper receiver and check for any looseness.
There was no wobbling and the fit was fine, so it's finished.
Incidentally, although it doesn't affect performance, applying Bellhammer grease to the part of the upper receiver shown in the next photo will make the bolt release mechanism move more smoothly.
Next, we'll fine-tune the settings for the FCU Leviathan.
FCU Leviathan Initial Setup
From here, we'll determine the settings for the FCU Leviathan.
The rotation detection for the selector and sector gear has been changed to an optical system, so we will proceed with calibration.
Selector position setting
Connect the FCU to the app and let the FCU remember the selector's position information.
Next, tap the area marked with a red circle on the screen.
Tapping will take you to the next screen.
If you proceed, you will be taken to the next screen.
When you switch to Safe mode on the screen shown in the picture above, the reflectivity of the light will likely be displayed. Since Safe mode is the black part of the selector's sticker, the reflectivity will be low, and it will say 26% is OK.
Setting the selector to "Semi" will transition to the next screen.
The display shows that the reflectivity is 53% at the cicada's position. The cicada is located on the mottled part of the selector's sticker, so a reflectivity of 53% is correct.
Finally, check the full auto mode.
The sticker for the full position on the selector is pure white, so the reflectivity is 86%, which is OK.
There is approximately a 30% difference in reflectivity at each position, so we can switch between them reliably, and that concludes this process.
Sector gear detection settings
Next, we will perform calibration of the sector gear detection.
Tap the red circle on the next screen.
Tapping will take you to the next screen.
If you fire just one shot in semi-automatic mode, you'll get the following data.
This likely allows you to select the detection range for each sector and the points to detect.
If you want to stop immediately upon detection, move the point to the left; otherwise, move it to the right.
For now, I've placed it in the middle.
The sensor's light intensity can be adjusted. Surprisingly, increasing the intensity doesn't necessarily increase the detection range, so find the optimal setting.
This completes the basic setup.
From here, the process involves finding settings that suit your own usage environment, which I will explain in the next installment.
If you're interested, please join me.
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