Airsoft G.I G4 Blowback series airsoft gun review:

I purchased the G4-A2 Sand Hog. Although there are many different models, they are all basically the same, due to the fact that the gun is a G&G Combat Machine Blowback M4. The only differences between the different models is the length, sights, color, and rail system (either "SOCOM GEAR Officially License Daniel Defense RIS", or "Rail interface system" not specified by ASGI).

NOTE: This review will be very similar to Hydra's Combat Machine review.

The G&G Combat Machine:
The G&G "CM" is a "sportline" of G&G. You may think of sportline as similar to a JG or Echo 1 because of Classic Army's poor performing and built sportlines. The G&G is a great built, great performing airsoft gun, unlike CA's sportlines. For more in dept reviewing of this gun, read on.

First impressions:
My first impression is "Meh" only because it came in a slip off cardboard box, with the gun itself in a flimsy plastic mold, no padding, foam, or even cardboard cushioning the gun. Once I got past the packaging I saw the gun and my thoughts went from "Meh" to "Wow!” in an instant. This gun is a perfect weight for me at roughly 10 lbs and looks magnificent. Without the orange tip it would be easily mistaken for a real gun. The gun came with a 450 round, metal high cap, flip up sights (depending what model you get) and a Noveske KX3 flashider (again, depending what model you get).





Externals:
The body is made up of a strong, durable, nylon body. The body is lighter than aluminum but stronger then metals such as "pot metal" found on most low-end guns. Although the body is very nice there is one flaw. There is very unsightly seem lines around the body (see below picture) The [non-functioning] bolt catch, magazine release, charging handle, dust cover, trigger, selector switch, trigger guard, forward assist, buffer tube, RIS, flip up sights, and outer barrel are ALL metal. The dust cover and forward assist seem to be made of a different, more silvery metal as the rest of the metal parts.



The RIS (Socom Gear Daniel Defense) Is filled with trademarks. Even on the inside there is accurate trades. It is also a free float rail system, which is very cool.




The flip up sights that came with my gun seem to be made by two different manufactures. From my observations the front sight seems to be the "B-2 front flip up sight" and the rear sight seems to be the "D-boy flip up rear sight" In addition to this strangeness, they are not the same sights as the picture depicts on ASGI's web site. I have one complaint about the sights and that is, the latch that holds down the rear sight falls out frequently. I simply just took it out for good because I do not have an optic to attach to my gun thus have no need for the sights to be flipped down.




The crane stock is like any crane stock. It is nice and durable and fits the battery nice, although there was a bit of wobble, but nothing some electrical tape can't fix.


Everything else does not need any explanation because it functions just like any M4 without any problems and looks great too!

Magazine- I would like to say one thing about the magazine. The little hole in the magazine where the magazine catch "catches it" seems to be a bit too small for the catch to fit in perfectly. What I did was took off the metal casing of the magazine and took a small file to the hole until it fit perfectly. An easy fix. In addition the magazine feeds great, although every 50 or so bbs it skips one or two, no big deal, just get some mid-caps and the problem will disappear.




Internals:

Hop up- The hop-up unit is constructed of a grey plastic, but seems so be hard enough to not be damaged by normal use. It has one trademark on it witch says "G&G SR-16". Inside the hop-up unit there is a lime green bucking witch it properly lubed, something you don't normally see. The barrel is made out of aluminum and seems to be of nice quality. For performance, read on...

Gear box- The gear box in this gun is a version 2, just like any other M4 variant. Although it is a V2, there are some differences because of the blow back feature. This includes a retaining clip on the top of the gear box as well as the blow back mech. The disassembly of this can be found here:

http://www.airsoftgiforum.com/viewtopic.php?f=12&t=8876

Be aware that the retaining clip is on very tight. After opening the gear box I took a look inside and it is just like any other gear box besides the anti-reversal latch, it is not like a normal AR latch., but instead has two latches, one keeps the gears from reversing, and the other keeps the latch in place. But other than that, same ol' gear box. The stock shim job was decent, but when re-shimming, I had to take out more shims then I needed to put in. The proper shim job raised the rate of fire 2-5 more bbs per second. The lube job was horrid, loose grease where it wasn't supposed to be and hardly any where it needed to be. The proper re-lubing probably helped the ROF as well. I was impressed with the overall gear boxes' quality. The quality and precision of every part was impressive. Only the cylinder head seemed to be made of a little lesser quality plastic then the rest of the parts inside. Speaking of the cylinder, the cylinder and piston assembly makes very good compression. The cylinder is different than regular cylinders. There is a small hole toward the front of the cylinder which has to be lined up with the blow back mech. If you take yours apart, you will see, it is not anything complicated. Finally the trigger mech. once installed into the gun it sticks sometimes when pulled, this can be annoying, but fear not, the vibrations of the gear box knock it out of place again so you don't have to worry about unintentionally spraying all over the field when your finger isn't even on the trigger! This can be fixed by lightly sanding where the two pieces make contact (NOT THE METAL CONDUCTIVE CONTACTS) and then adding some lube very lightly, you could also just get a new trigger mech. if you would like.


This is the complete gearbox, as you can see all the parts stay nicely in place, even under tension from the spring

These are all the parts that make up the cylinder and piston assembly. Piston/head, Cylinder/head, tappet plate, air nozzle, spring, and spring guide.

These are the gears and the odd AR latch. They seem to be of good quality and also made with precision. Enough said.

AR latch.

AR latch in place inside the gearbox. As you can see that piece screwed into the shell keeps the AR latch in place. You can also see here that the bushings are made of copper or brass, sort of strange knowing both of those metals aren't very hard. One good thing though is that they are big, which means you can replace them with ball bearing bushings.

Close up of the cylinder head.

Close up of the piston/head.

How the Blowback works- Bear with me through the text, the video below will explain everything… The blow back uses air from the cylinder pushed into another cylinder through a hole, to push on a piston, which pushes back on the piston rod, which finally pulls the bolt back. In order to disassemble this mech. please watch the video linked below. This video will explain the mech. as well as give step by step instructions on how to get it apart.

In my opinion the blowback mech isn't anything special, although it does work flawlessly and gives the gun that little bit of extra realism.

http://www.youtube.com/watch?v=O9_2xfdKzVw

Performance:


Accuracy- The accuracy with the stock hop-up unit is quite nice. At roughly ~100 ft. I am getting about 5-10 inch grouping, an easy hit. At about ~150 ft. the groupings get larger and any farther than that the bbs start to fall or curve to one side. I installed a Madbull bucking and the groupings got a lot tighter and I was able to reach longer distances. Overall the stock accuracy was impressive, especially for a $200 gun.

FPS/ROF- ASGI clocked my gun at about 400 FPS, in my opinion this is a bit too much for a assault rifle. I dropped in a M100 spring and am now getting ~330-350 FPS, perfect for me. The stock ROF was unimpressive at about 8-10 bbs/sec. From the help of "Audacity" I have calculated that with a fully charged 9.6v battery, and a properly shimmed gear box I am getting ~ 13-15bbs/sec. As you can tell the stock motor isn't the best, If you want higher RoF you can get a better motor.

Conclusion:


For the price you are paying you get very nice set of externals as well as a great set of internals. A few things could be a bit nicer, but everything can be easy fixed without playing over $50 or so. I would recommend this gun to anyone who is on a $300ish budget and want a great looking, and performing gun.

If you have any questions just PM me or send me a message on my Youtube channel: www.youtube.com/STORMairsoftRevies

This post has been edited by hydralover: Mar 11 2010, 10:45 PM