LCT AK74 NV response-enhancing custom build completed.

So, last time we finished adjusting the shims.

We'll continue from where we left off this time.

Greasing and assembling the gearbox

Now that the shim adjustments are complete and the preliminary steps for assembling the gearbox are finished, we'll apply grease to each component.

Basically, I use Bellhammer's extreme pressure grease No. 2 where metal touches metal, and GAW's extreme pressure grease with a brush for other areas.

Bellhammer No. 2 Gold Grease
This is a classic, top-quality grease. No. 2 has the same ingredients as No. 0 but with a higher viscosity. I primarily use it for metal-to-metal connections.

GAW G-GREASE
This is a standard grease. It has a lower viscosity compared to the Bellhammer Gold series, so I use it inside the cylinders of both electric and airsoft guns. It's a bit pricey, but the quantity is large, so in the end, it doesn't feel overpriced.

The following photo shows an example of where to apply the grease. (The brown is Bellhammer and the white is GAW grease.)

Apply grease to each component. An ice-making mold can be used as a tray.

Next are the spring and spring guide. To prevent spring noise, apply Tokyo Marui high-viscosity grease to the entire spring.

I initially intended to use an M100 spring here, but I chickened out and went with an M95 instead. This would later lead to trouble.

Now we'll assemble the gearbox. The following clips will be helpful when assembling the gearbox.

The product is called "MLEmart Airtech Studios GIK Gearbox Installation Kit (Trigger, Anti-Reversal Latch 2-Piece Set) [Compatible with Electric Gun Ver.2 – 9 Gearbox]," but it seems that the trigger part is only compatible with Ver.2.

• Gearbox Installation Kit
This might be useful for those who aren't used to closing the gearbox. You can manage without it, though.

Here's a tip for assembly: LCT springs have long spring guide tabs, so hook the spring and guide onto the gearbox beforehand. The trigger area is very difficult to assemble, so it's easier to first assemble the gearbox without the trigger, then slightly open the gearbox and insert the trigger.

The part circled in red is sandwiched between the gearbox, so be careful not to forget to assemble it. I forgot to assemble it and had to redo it.

The gearbox assembly is now complete.

MOSFET installation and wiring creation

Next, we'll work on the electrical system. First, we'll start with the motor wiring. We'll determine the length of the wires based on the original wiring and cut them accordingly.

By the way, I'll be changing the wiring to 1.25 sq.

I'll attach Eagle Model's gold-plated Faston terminals (type 110) to the cut wires. I'll solder them on just in case.

Next, cover them with heat shrink tubing. Make two of these, one for the positive terminal and one for the negative terminal.

Next, solder the motor wires to the MOSFET. Be careful not to leave the solder on for too long, as the heat can damage the circuit board. The trick is to solder each wire one by one.

Next, connect the signal wire and the wiring going to the battery to the MOSFET and cover it with heat shrink tubing.

Next, we'll create the wiring to connect to the battery. We'll change the connector to a T-type and install a 30A fuse. Also, silicone wire is recommended over Teflon wire for the battery wiring. Teflon is hard, but silicone is soft, making it easier to handle.

For detailed instructions on how to install the MOSFET, please click here.

Next, we'll make crimp connectors to join the wiring that connects the MOSFET to the battery. Make sure to use male and female connectors to avoid mixing up the positive and negative terminals. Then, cover them with the usual heat shrink tubing.

The reason I'm using these crimp connectors this time is that with the AK's fixed stock, the rear wiring is impossible because the connection between the stock and receiver is too narrow for the connector to pass through. So, I have no choice but to run the MOSFET wiring from the receiver side and the battery wiring from the stock side and connect them together.

Similarly, we'll create a crimp connector on the MOSFET side as well.

Now we'll temporarily assemble the gearbox into the receiver and do a test drive. At this point, we'll attach the selector switch components to the gearbox beforehand.

A common mistake people make here is forgetting to install the return spring for the switch's cutoff, otherwise the semi-automatic mode will malfunction, so be careful.

I attached the motor and grip and did a test drive.

By the way, the gearbox won't fit into the receiver unless you put it in before attaching the motor. I was desperately trying to put the gearbox with the motor attached into the receiver, but it was impossible.

This is a video of the gearbox being tested.

LCT AK74NV Electric Custom Gearbox Test Run

At first, I tried to run the wiring with the stock still attached, but it didn't work.

Don't be lazy; it's definitely better to remove the stock.

Also, pay attention to the position of the selector gear. I assembled it incorrectly and ended up with a very dangerous situation where the safety was in full-auto mode.

That concludes the main unit.

Chamber assembly

I'll take a quick look at the chamber before disassembling it.

It's a pretty standard, so-called AK-type chamber. Just remove the screws and barrel lock and take it apart quickly.

Next up is the LAYLAX Delta Strike barrel that I'll be assembling. It's a loose-type barrel with an inner diameter of 6.20mm.

　　

The hop-up window is quite long. The hop-up packing mounting part is made of resin and kept coming loose, so I glued it in place with super glue.

Next is the hop-up packing. This time, we'll be installing Airsoft97's "Neko Nade Long-Hanging Packing." Hop-up packing is a slick type with no protrusions.

Attach the bucking to the chamber.

The hop-up rubber is extremely long and thick. In the case of the LCT, no modification was necessary on the chamber side.

Next, we'll assemble the packing. As usual, apply Tokyo Marui high-viscosity grease to everything except the hop-up window, install the packing, and wrap it with sealing tape.

Next, assemble it into the chamber and check the hop-up setting. The left is hop-up 0 and the right is hop-up maximal.

I feel like it's lacking a bit of protrusion.

I assembled it and tested its firing performance, but the amount of air expelled was insufficient for the barrel, and the muzzle velocity didn't even reach 90 m/s.

Even if I increase the hop-up, the initial velocity doesn't decrease, but it doesn't increase either.

I no longer had the energy to open the gearbox, so I gave up on the high velocity and decided to use the stock inner barrel and a Miyagawa Rubber long-range middle-strength 60 rubber that I had lying around.

Upon investigation, the original inner barrel appears to be a tight barrel with an inner diameter of 6.02mm. I checked for bending, but it was fine.

Looking back, I think the reason for the low initial velocity in the high-flow setup wasn't just the amount of air being discharged, but probably also that the hop-up's pressure was too weak, resulting in low initial velocity. Adding a rubber sheet to the slick packing or increasing the pressure of the rubber might have resulted in a higher flow rate.

I also suspect that changing the spring from an M100 to an M95 because I was worried about exceeding the initial velocity limit might be the cause. It's not that the parts are faulty. Probably.

I've decided to use the stock inner barrel, so I'll do some modifications. The tip is just cut off, so I'll taper it and round the hop-up window so the hop-up can descend more easily.

Before processing

After processing

Next up are gaskets from Miyagawa Rubber.

Attach this in the same way as before and check how much the hop-up protrusion is lowered.

It's looking good. Centering the gasket is a real pain with this type of gasket, but I've finally gotten the hang of it.

I feel like everything else is fine as it is now.

To give you a little advertisement, I think it's a very good gasket if you assemble it properly in the center.

The airtight seal is good, and the gasket opening is neither too wide nor too narrow, almost identical to Tokyo Marui's. The downsides are that centering it is difficult, and because the outer diameter is slightly larger to maintain airtightness, assembly can be tight depending on the chamber.

Next time, I'll do a comparison of ballistics with different packings (I've actually done this, and it's described in the ballistics verification section of this article).

Now we just need to assemble the exterior and we're done.

Live-fire performance measurement

Finally, it's time for the usual live-fire performance test.

The conditions are the same as always: ET-1 REDLINE 1200mAh 7.4V battery used with a storage voltage of 7.65V, Tokyo Marui bio BBs 0.2g, and hop-up set to 0.

It's looking good. I achieved my usual target of under 95 m/s with 0.2g of BBs.

After measuring several shots in semi-automatic mode, the variation was ±0.25 m/s, the lowest I've ever seen. Is it because the barrel is longer? Or did I somehow manage to assemble it in a miraculous way? I'm not sure.

Next is the cycle.

It's looking good. With a full charge, it should be able to fire around 20 rounds per second.

If you're interested, please also check out my review of the chronograph.

This time, since I didn't do any sector cutting, anything over 21 rounds per second would be dangerous, so this was a success.

For reference, response

This is a semi-automatic video.

LCT AK74 Semi-automatic after customization

This is a fully automatic video.

LCT AK74 fully customized

The cicadas are great because my fingers (as an old man) can't keep up with them.

I haven't measured the noise level, but it seems quite quiet.

If you'd like, please compare it to the product straight out of the box here.

This is completed.

The finished exterior

Finally, I attached GAW's magazine spacer, a side rail I had lying around the house, and a red dot sight, and that was it. For someone like me who isn't used to changing AK magazines, the magazine spacer is incredibly helpful.

The finished product

The grip's color isn't very good, so I'd like to change it later.

LCT LCK74 AK74 NV AEG
I think this is one of the best electric, wooden-stocked AK74s I've ever seen.

Deployment in combat and ballistic testing

As of this writing, the COVID-19 lockdown has finally ended and we've been able to put our equipment into practical use (though it seems like another lockdown to prevent further spread is likely).

I tested it at Yanex's regular meeting, a forest-type outdoor field in Noda City, Chiba Prefecture.

Regarding the initial velocity, I measured it at home with a 0.2g BB to be under 95m/s, but for some reason it was around 97m/s in the field, which surprised me.

First, I adjusted the hop-up at the range using 0.2g BBs. I usually use 0.25g BBs, but I had some 0.2g BBs left over, so I wanted to use them.

With just a slight adjustment of the hop, it achieved the correct hop setting, and it looks like it can handle BBs down to about 0.3g.

From what I could see, the trajectory was straight up to about 40 meters, then it rose up and seemed to drop at around 50 meters or more.

I adjusted the red dot sight to zero it at 40m, and now it's fairly accurate within that range.

We've also compiled a comparison of trajectories based on the different hop-up packing designs and how they're compressed.

It seems like it would go even further with heavier BBs. The muzzle velocity and hop-up adjustment range are sufficient, so I can adjust it. Next time, I'll try it with 0.25g and 0.28g BBs.

I was able to fire around 1500-2000 rounds in total during the game using just one 2000mAh LiPo battery, so it didn't seem to have poor battery life.

The firing cycle was just right, neither too fast nor too slow, as intended. Even in semi-automatic mode, it kept up with my burst firing, so there were no problems.

Also, thanks to my efforts, the firing sound was quiet, and even when I fired at an opponent about 15 meters away, they didn't notice the sound.

Furthermore, the notoriously difficult task of magazine changes with AK-type rifles was significantly improved by GAW's magazine spacer, and I never made any mistakes when changing magazines. It was completely hassle-free.

It turned out nicely, but it does have a drawback: it's heavy and long, making it somewhat difficult to handle.

I used it in a fairly large outdoor area this time, so it worked fine, but it seems like it would be a bit difficult in fields with many intricate structures.

The weight also subtly becomes a factor as you play more games.

But you can overcome those issues with a touch of romance.

Based on my experience using it in actual combat, it turned out quite well, so I'll continue using it as is for a while.

For measuring initial velocity and checking trajectory, white is recommended for better visibility (black is difficult to see). I personally prefer G&G, so I recommend them (they're not as accurate as Tokyo Marui, but they offer good value for money).

G&G Bio-Bullets 0.2g
It's inexpensive and accurate, so I use it for a wide range of purposes, from performance testing to airsoft games. It's been my favorite since it first came to Japan (around 2008). It lasts a long time for a biodegradable product.

G&G Bio-Bullets 0.25g
It's 0.25g. I generally use 0.25g BBs when playing airsoft.

Final specifications and considerations

So, here are the usual final specifications and recipe.

I think the cost was relatively low this time. Around 12,000 yen plus my own labor cost, which is priceless.

This resulted in a responsive, slightly high-cycle rate of 18-20 rounds per second.

While not all individuals will be exactly the same, we hope this can serve as a general guideline.

My impression is that the customization itself was easy, but assembling the exterior parts was difficult because they were stiff and the clearance between each part was too small.

While it might be partly because I'm not personally familiar with AKs, the fastening and fitting of each part was incredibly stiff.

I hope you find this helpful.