GGI REVIEW: GHK's gas blowback AK74U (in progress)

[GBBNut]

Hello boys and girls! Here's a look at one of the most anticipated modern gas blow back airsoft rifles of the year! GHK's gas blowback AK74U! For those of you going WTF?! Here's the basics: the talented technicians at GHK managed to stuff gas blowback internals into a DBoy/Kalash metal AK and feed it with a self-contained gas magazine. For those of you out there who were looking for a modern gas blow back AK - here it is! This fantastic toy is distributed worldwide by RA Tech.






Field Stripping
Disassembling the GHK gas blow back AK74U couldn't get any easier. For those of you who are familiar with the real AK47 this part will be a breeze.

Helpful Tip: Always start by removing the magazine and check to make sure that your airsoft gun is safe and the barrel is clear.

Open up the top cover to gain access to the internals. Push the op rod forward, rotating it to either side, then removing it by pulling it rearward. It may be necessary to push the rubber insert forward so that there is enough room for the op rod.

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Next, remove the rubber insert. It's a large block of solid rubber pressed into place at the rear of the receiver. If you're encountering some difficult removing this part, just tip it forward and then it should come out.

[GBBNut]

Removing the bolt and bolt carrier assembly is nearly identical to the real AK. Just take hold of the charging handle and slide it to the rear. Remember to place the selector on semi or auto otherwise the bolt carrier assembly won't be able to travel back far enough. Once the rails on the sides of the bolt carrier assembly line up with the gap in the receiver, remove it and set it aside.

And that's all there is to it. Quick, easy, simple. The GHK stays true to the legacy of the legendary AK47.

[GBBNut]

GGI TV - Test firing the gas blowback AK74U!

[GBBNut]

Here's a quick look at the gas magazine for the GHK gas blowback AK:

Top of the mag.



Main valve (back) and fill valve (bottom)



One thing I noticed was that every time I changed mags the firing pin would push the main valve and release a small amount of gas. Not a big deal but it's something that could be improved upon. Also, there is a definite cool-down issue with these mags. After three or four mag refills you can feel the top of the mag getting colt. That's because of how much green gas this mag can hold. Excessive full auto fire just adds to the cool down effect. Later I'll upload pics of the mag disassembled.

[GBBNut]

The GHK AK uses a hybrid KSC G-series / WA Magna blowback system. It's a KSC front with a WA back and a WA Magna style blowback unit. Oddly enough I was discussing just such a mod for the WA M4 in our GGI Think Tank section. Great minds think alike! To accomplish this, the loading nozzle is a two piece design made out of a thick plastic. The material feels a bit on the cheap side but the thickness more than makes up for the difference. Metal pins hold the entire assembly together.

The following pics show some mods I've already done to the GHK. They are not necessary at all. One of these mods I'm not sure can even be called a mod... Here I've installed a heavily modified charging handle spring from an AEG. It was obvious that the original designers intended for there to be a spring to pull back the loading nozzle (ala WA Magna blowback system). However, there was none to be found when I opened it up so I just installed one myself.

Note: Please do not ask me to go back and take pics of this mod. It was a severe pain in the rear.

Next I opened up the loading nozzle. I was hearing some strange rattling sounds coming from inside so I had to figure out what it was. After I popped out the pin the culprit was clear - a large ball bearing?!?! While it was a crude and effective solution, living up to the true nature of the AK, it just wouldn't due in my gas blowback AK. So I dug up a rocket valve and threw that in there with a stronger valve spring. So far it's holding up pretty well (made the video after these mods).


UPDATE 11/02: Apparently GHK & RA Tech cannot install a KSC rocket valve due to the design patent held by KSC and their OEM manufacturer KWA. So all production AK's must come with the ball bearing instead.

Oh yeah... when performing these mods don't forget to reinstall these screws!

[GBBNut]

Next is the hopup unit. This has been an Achilles heel for both the WA M4 and Inokatsu M4. So how did GHK do? Take a look for yourself.




This hopup unit is designed like an AEG hopup. Instead of forcing BBs into the hopup chamber, they are pushed up into the hopup chamber like AEGs. On the down side, the GHK AK will "drop BBs" whenever you change mags. I haven't tried it out but don't worry, range and accuracy tests are to follow.

[GBBNut]

Here are more detailed photos of the hopup unit. It's a one piece design with a dial that spins nearly 360 degrees - talk about a lot of adjustment! The only improvement I can see is to add "teeth" inside the dial just like the WA M4 design. This would keep the hopup from possibly unwinding in the middle of a game. Other than that this is a great design.

As you've probably noticed, this gas blowback airsoft gun can use AEG hopup buckings and inner barrels. This is a very nice feature for an already impressive product.

[GBBNut]

Here are some extra photos showing other differences between the AEG and the GBB AKs.

The pistol grip


Magwell

[Majorpeaches]

Looks good and thanks for getting a review started. Do you think the sluggish recoil is going to be a problem on all the guns that don't do a mod like the one you did? that would be a big turn-off.

Cant wait to see how it performs

Also, is that video made before or after you did the mod to fix the recoil?