KSC AK74M system7two Quick Disassembly Review

In the previous review, I covered the KSC AK74M GBB's appearance, so this time I'll perform a field strip and some light maintenance before reviewing its shooting performance.

Let's get started by disassembling the field strip.

Disassembly (field strip level)

Remove the top cover. To remove it, press the button shown in the picture while removing the cover.

Once the top cover is removed, it will look like the following picture.

The recoil spring is simply fitted in place, so it can be easily removed.

The recoil spring has the following shape. Incidentally, although I don't recommend it, you can achieve full stroke by removing the part where the bolt makes contact.

Next, remove the bolt. You won't be able to remove the bolt unless you cock the hammer, so pull the bolt towards you to cock the hammer.

There's a little trick to it; in the case of this product, the blowback engine nozzle gets caught on the hammer, so you need to push the nozzle a little.

You can remove it by pushing it to the position shown in the next picture.

This will allow you to remove the bolt upwards.

Looking closely at the bolts, the first thing we see is the locking lug.

The male rocking lug is reproduced, but it is made of resin.

Next is the blowback engine.

It contains a fairly large gas seal (the light yellow part). This is what generates the powerful blowback.

If you're interested, I've made a video explaining the operating mechanism of gas blowback guns, so please take a look. It's the same principle if you consider the slide as the bolt.

Finally, here's the tip of the long-stroke piston, a characteristic feature of the AK's operating system.

The real thing gets dirty with soot here because it catches the combustion gases, but this is a gas gun so it stays clean.

The total weight of the bolt was 206g, which is neither heavy nor light—just average. It seems to be slightly lighter, perhaps with an emphasis on ease of operation.

This concludes the introduction to Bolt, and it's quite realistic.

Looking inside the hammer mechanism of the main body, it's quite realistically made.

The hammer is lying down.

Each part is made by sintering and is basically made of iron, so I think it's quite durable. By the way, sintering is a manufacturing method in which iron powder and an adhesive-like substance are mixed, poured into a mold, and then baked to harden.

Compared to casting and forging, sintering offers a much greater degree of freedom in shape, but because it's simply made by solidifying iron powder, its strength is relatively low for an iron product (though sufficient for airsoft guns). Incidentally, the United States excels at sintering, and this manufacturing method has been widely used for internal parts of handguns and other firearms since around 1900.

This manufacturing method is difficult because it requires considerable know-how regarding the components and quantities of iron powder and adhesive (KSC is an expert at this).

Next, I'll introduce the bolts that secure the side mount, but I strongly recommend applying threadlocker to them.

In most cases, it's loose. At worst, the side mount can come off due to the recoil from the blowback while you're playing.

Loctite High Strength 263 Threadlocker
As a precaution, this threadlocker is corrosive to plastics, so it's best to use it only on metal.

Next, we'll remove the handguard. Lift the lever located near the rear sight.

Next, the upper part of the handguard can be removed.

The bolt rod runs through this handguard.

Next, remove the lower handguard. Lift the lever located on the muzzle end of the handguard.

This concludes the field strip level decomposition.

Basic maintenance should be completed with this level of disassembly.

If you need to replace the inner barrel, hop-up packing, etc., you should be able to access them by removing the bolt shown in the following picture (I haven't done it yet).

It is fixed very securely, so there is almost no wobbling of the barrel.

Finally, let's take a look at the hop chamber.

Unusually for KSC, this can be adjusted with a dial without the need for tools. Incidentally, you can access the adjustment by pulling the cocking handle without disassembling it.

Personally, I would have liked to see the female locking lug design, like on gas blowback M4s (but I guess it can't be helped).

Reassembly can be easily done by following the reverse procedure.

In my case, I apply my usual Bellhammer No. 2 grease to the moving and sliding parts, and KSC's silicone oil spray to the hop-up packing and gas route before assembling.

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.

KSC Genuine New Gun Oil 430ml
Any silicone spray will do, but KSC's is convenient because it comes in a large size.

Live-fire performance verification

Now we'll check the actual shooting performance. For reference, this is a completely unmodified unit that has been used quite a bit while undergoing regular maintenance.

The conditions were as follows: gas, HFC-134a, was used to fill the magazine completely, and the surface temperature was set to 22°C (outside temperature was around 20°C).

However, unlike usual, the magazine is covered in resin, so the actual surface temperature of the gas tank is unknown. It is probably lower than the surface temperature of the magazine. Also, because the magazine is covered in resin, it is less affected by the outside temperature, so it seems to be resistant to cold (insulating effect of resin). On the other hand, be aware that it will be difficult to warm up if you try to heat it up.

The ammunition used is S&T 0.2g bio BBs.

This is the initial velocity.

With 0.2g BBs, the muzzle velocity is a very high 88m/s, and as recorded by the chronograph, it maintains this velocity even after 23 consecutive shots, showing very high performance.

Next is the cycle.

It fires approximately 9 rounds per second, which works out to about 540 rounds per minute. This is slightly slower than the 600-650 rounds per minute of a real gun. However, this rate will increase with higher ambient temperatures and decrease with lower temperatures, so please take this as a rough estimate.

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

Next, let's look at fuel efficiency.

First, the weight of an empty magazine and the weight of a magazine full of gas.

I can hardly believe it, but it took about 64g of gas to go inside.

Next is the weight of the magazine after firing 42 rounds in a random sequence.

I used about 12g of BBs over 42 shots. This works out to about 0.285g per shot. Considering it's a long gun with a long stroke, I was surprised by its fuel efficiency.

I fired about 42 more rounds.

I lost about 11g after 42 shots.

I continued firing until it stopped working, and it fired a total of three and a half magazines' worth of rounds, which is quite impressive performance (about 147 rounds).

Next is a video of actual firing. After firing about three magazines, the magazine is switched to dry-fire mode.

KSC AK74M Gas Blowback Semi-automatic

KSC AK74M Gas Blowback Full

It's moving around quite energetically. The noise is incredibly loud, which really adds to the atmosphere.

Incidentally, the trigger pull has a nice weight to it, but it's not a two-stage trigger. However, you can feel where the sear drops.

This video shows the AK rifle in operation with its removable cover removed to help understand its mechanism. It's quite dangerous, so be careful if you try to imitate this.

KSC AK74M Gas Blowback Full Field Strip Operated

I'm so satisfied with its performance that, unusually for me, I haven't done any customization at all. If I were to change anything, it would probably just be to lower the muzzle velocity, which is a bit too high (by just slightly trimming the flow valve spring).

It's quite well done.

I haven't used it recently, so my memory is a bit hazy, but I think it had a low trajectory up to about 40m, then rose from there, reaching its peak around 45m.

Unfortunately, the indoor field in Yamanashi, Ajito, has closed down. At the Gas Blowback Guys Festival there, I was so unstoppable that I had to put it away in the afternoon because the trajectory was so good (there weren't many long gas blowback guns back then).

I had a ballistics test done at Yanex at the end of July 2021.

The conditions were an outside temperature of around 32°C, a full tank of gas, and G&G Bio 0.2g BBs, resulting in an initial velocity of 96 m/s. The trajectory was terrible, like a Sawamura Award-winning curveball that couldn't even get a strike, making it completely unusable.

The cause was that the hop-up packing had completely deteriorated due to age. I will be replacing the hop-up packing soon. Incidentally, considering that it's performing this well after more than 5 years of ownership, I think it's quite durable.

As a bonus, here's a comparison with the LCT electric AK74NV.

This is a comparison of the electric AK74NV from LCT, a company known for its high-quality AK rifles, with the AK74NV in terms of appearance.

Other side

Both are similarly well-made.

One of the biggest differences in appearance is that most of the LCT's exterior is made of iron, so the texture and weight are quite different from the KSC.

Another significant difference is the grip shape; KSC's gas blowback model has a much thinner grip.

By the way, since I don't own any Russian optical equipment, I've mounted a C-MORE type red dot sight from UFC, which I think is similar.

The site picture will be at the perfect height if you apply a mask at a moderate height, like this:

- No-brand AK side mount QD type
My unit didn't require any adjustment, but some units might need it.

- No-brand C-MORE type dot sight
My own is from UFC, and since UFC is the distributor in Yutani, I think it's pretty much the same as the unbranded products sold to the general public.

Summary

This product is from around 2012, but it's very well made, and I don't think it's inferior to recent gas blowback pistols in terms of performance or appearance.

The appearance is quite good, and the shooting performance is so good that there's really nothing to modify. If I were to do anything, the only thing I can think of is replacing the old hop-up packing with a new one.

I've owned and used this for over 5 years without any problems. There are no gas leaks due to aging or frequent jams due to nozzle deformation. However, there are a few screws that loosen due to vibration, and the hop-up valve is completely dead.

I have absolutely no idea what kind of performance Tokyo Marui's upcoming AKM will have, but I don't think KSC's AK will be inferior (I think Tokyo Marui's will have pretty good shooting performance).

Surprisingly, the prices are also quite competitive; Marui's is priced at 65,780 yen (including tax) at the time of writing, while KSC's is 54,800 yen (including tax), making KSC's seem like a better deal.

However, the single biggest drawback is the magazine, which is expensive at 8,690 yen including tax, and weighs nearly 850g when fully equipped. I own about four of them, three of which are in pouches, and that alone weighs 2.4kg, which is about the same weight as carrying three gas blowback handguns. This weight, surprisingly, contributes to fatigue.

I don't know the exact price of Tokyo Marui's magazines at the time of writing, but since their M4 magazines were relatively inexpensive at around 4,000 yen, I assume they'll be around the same price.

The AK74M and AKM are actually different models and don't compete with each other, but if you're simply looking for a gas blowback AK, I hope you'll consider KSC's options and refer to this article.

By the way, I like the shape of the AK74 series, so I'm holding off on buying Tokyo Marui's AKM.

That concludes my introduction to KSC's AK74M GBB, even though it's a bit late.

It was discovered that the hop packing was worn out, so next time I will show you how to replace the hop packing.

KSC AK74M Gas Blowback System 7 Two
KSC has been doing quite well lately, and they've re-released some items. I recommend them.

KSC AK74 series magazines
Since these items often disappear from the market, I recommend securing them while you still can.

KSC AKS74U Gas Blowback System 7two
This is a short model of the KSC AK74 featured in this article, with almost identical performance and structure. It's what's commonly known as a Krinkov.

KSC KTR-03 Gas Blowback System 7two
This is a KSC AK74 Tactical Model. I believe its structure and performance are the same as the AK74m.