Internal Review of the G&G Combat Machine / Airsoft GI G4 Series
Hope you enjoy the review, and I hope to write up some more!First Impressions
When I opened the gearbox, there where a few things that caught my attention. The first thing I noticed is the anti reversal latch (ARL), stayed in place very nicely as seen here.
It was not your typical ARL that flings off, or is impossible to keep in place. It is crafted with great precision.
The next thing I noticed was the rack gear (teeth on the piston). The second to last tooth on the piston was absent, as shown in this picture.
This helps with correcting your AOE (angle of engagement). Just this by itself will not correct AOE, however it does make it easier. It also helps prevent premature engagement with the sector gear, a common problem in high rof setups. The polycarbonate used for the piston is very soft, and can strip very easily. If you want to run a setup that is greater then the stock setup, I would recommend you change the piston. When the gun is in it's stock form, the piston will last for a while, but otherwise, I would change it.
The next thing I noticed, that is clearly a fault, is the cylinder port as seen in the picture below.
The picture compares the stock G&G cylinder (blue) to a stock clone MP5 cylinder (brass) which is a Type-2. You can clearly see the port on the G&G cylinder sits further up then the Type-2 cylinder. This will cause a noticeable lose in range, fps, and overall air output. I would definitely change it with a Type-1 cylinder, as that is the proper type for a M4 length barrel. The cylinder itself is very smooth, and gives great compression, provided the other compression components work with it. However it still needs to be replaced as it is the wrong type.
The cylinder head (shown in the following pic), is made of cheap polycarbonate.
It will hold up fine in the stock setup, however it could crack if you run a heavy spring or an aluminum piston/piston head. Padding it will help, although a new head altogether would be best.Further Disassemble and Inspection of the Gearbox
The next gearbox component we see is the air nozzle and tappet plate.
Nothing special about them, just your everyday nozzle and tappet, and they both do their job just fine.
Removing the piston head from the piston body shows that it does not have bearings like the proline, rather a plastic washer.
It is the same type used in the Proline, however the proline also uses bearings, this one does not. This next picture is a forward view of the piston head showing the ports.
As you can see, they have little swirls. It is suppose to help with the compression, however I really don't notice any benefit from them. Something that was a fault in the design, was that there are small ports in the back of the piston head. This lets air escape giving you horrible compression. The fallowing pic shown below, shows you the ports in the back of the piston head.
The compression and air output/efficiency was horrible. The gun was missing a good 30-50fps do to the poor compression. This gun could definitely use some improvement on the compression. A new piston head and cylinder can give you an increase of 30-50fps.
Here we see the spring and spring guide.
The spring is just that, a spring, nothing special or out of the ordinary. The spring guide is non bearing, and solid metal. The quality is decent, about on par with a clone gun.
Removing all of the upper gearbox components, exposes the front end of the gearbox shell as seen below.
I would not consider it "reinforced" though it is built very strong. It will hold up very well for a stock V2 gearbox.
Here we see the gears, which are standard ratio and made of steel. If you look closely, you can see the spur gear has "G&G" stamped onto it.
These gears are not heat treated, and are on par with clone gun gears.
Removing the gears reveals the bushings.
They are made from cheap powdered brass, and can wear down (or in some cases, shatter) very easily. I would definitely replace them. In this particular model (X4-A1) it uses 8mm size bushings. After only a few hundred rounds they are already starting to wear down. Like I said before, I would definitely replace them.
Here we have the cutoff lever and safety.
They are both made from a very soft metal, so the cutoff lever could wear down easily under any setup with a high rof. The safety is also made from a soft metal, however it does not bother me, as safeties do not usually wear out very fast.
Next we have the selector plate. It is made from a decent polycarbonate, nothing out of the ordinary. If you look closely you can see it has "GR16" molded onto the plate.
However, when you compare it to another selector plate, you will notice that it is absent of the metal strip, which is normally used to complete the circuit when moved forward. The picture shown below compares the two types, the G&G (bottom) and the original/normal type (top).
Here we see the trigger contacts and wires.
As you can see, the metal on the back is already connected. This is why the selector plate does not need the metal strip, as the circuit is already half complete (the other half being one pull of the trigger). The contacts and the unit itself are great quality. I've never had a problem with G&G trigger contacts or trigger units.
The wires are very cheap, and very thin, they can short out/burn out very easily. I would definitely replace them if you plan on using anything past a 8.4v or 9.6v.
The motor (shown below, attached to the gearbox, it's a little hard to see) is not very good.
The motor will hold up fine pulling the stock M100 spring, but struggles greatly to pull a M120 or a M130 spring. The rof is not to bad, but definitely lacking, getting around 10rps with a 8.4v battery, and 15rps with 9.6v battery. G&G motors also tend to wear down VERY quickly (only takes a few hundred rounds to burn it out). However the pinion gear on the motor is fantastic! It is made from an incredible strong steel. I have never had any problems at all with G&G pinions, so there's no need to replace the pinion. Hopup and Barrel Components
Now we move onto the hopup and barrel.
The hopup unit itself (shown below, fully assembled) is made from ABS plastic, so heavy usage could break it.
Personally, I have never had any problems with plastic G&G hopup units, however I know a few people who have. It should not be a priority to replace it, though it would be wise to do so eventually.
The bucking (green, shown below, on the left) is very soft, so it will work better at low/normal fps setups.
At the stock fps (about 300 w/ .2g BBs) it gave fantastic results. It gave a very consistent hop, and had no trouble engaging heavy BBs (.28g).
Here we have the barrel.
As you can see, it is not the smoothest nor the most accurate. Having said that, it's definitely better then any other barrel for a gun in it's price range. The groupings it gave are decent. It got about 8-10inch groupings at 130feet with .2g BBs (max range of 150feet). I am not 100% sure of the bore size to this particular barrel, it will vary depending on which model you get. it will either be 6.04mm, or 6.08mm.Final Conclusion and Rating
Overall, it's definitely a good gun compared to other guns in it's price range (mostly clone guns). It does need some work and improvement though... It had some compression problems, replacing those parts will cost you a good $30. The motor struggles to pull an upgraded spring, and if it burns out, a new one will cost you a good $25+. The piston may not be the best, but it is definitely good and will hold it's own on the stock setup. If the wiring burns out, you can buy an aftermarket wire set which will cost you about $20, which is expansive, so I would recommend you just buy the wires at a hardware store, for as little as $10. The bushing are one of the worst things about this gun, and should be replaced. That will cost you about $15-$20.In it's stock form, the overall internal rating for this gun is a 5/10. Once all the kinks are worked out, it gets a solid 8/10.
It's a good gun for the price, though I expected a lot more from G&G. I would recommend it due to the guns externals (I'll get to them in a later review) and if you plan on working out the kinks.
Thank you for reading my review, and I hope this helped you chose what gun you should buy.