D-boys M4A1 BI-3681M Full Metal

[S.C.A.R]

Before you start to read this review, please take note that despite I have three years of airsoft experience, this is the first time I write a review about an airsoft gun, so please be fair to me. Thankyou!
Reason why I want to write a review about a gun that somebody had already written: I am a new person to this community but I found out that there’s only one review about this gun by Grady. Grady’s review isn’t bad, but it lacks some information about shooting reports and a look into the internals as well. Also, his grammar isn’t very good. With some gaps left in that particular review I decided to cover it all in my own review of the D-boys M4A1 BI-3681M Full Metal.
BOYI/D BOYS M4A1 Full Metal Version (Bi 3681)
Content Table
Real Steel History
Introduction
First Impression
The Box
The gun (Externals and internals)
Disassembly
Upgrades
Additional Informations
My own weapon upgrade
Future Upgardes
Shooting Report (Range and accuracy test, power test)
Skirmish Report
Evaluation
Additional Information
Pros and Cons Evaluation
Recommendations
Conclusion
Weapons Gallery

Real Steel History
[IMG]C:\Documents and Settings\user\My Documents\My Pictures\Colt M4A1 left hand side.bmp[/IMG]
[IMG]C:\Documents and Settings\user\My Documents\My Pictures\Colt M4A1 right hand side.bmp[/IMG]
First off, before the review, let’s start off with the real steel history.
Now here’s the part which I think most people will find boring on or even skip it, but it is essential in a review.

The Colt company developed various carbine versions of the basic AR-15/M16 rifle since 1970s. These carbines were intended for all markets - military, law enforcement, civilian. US Military (and some other armies, most notably - Israeli Self-Defense Forces) had adopted the Colt CAR-15 Commando and XM-177 carbines during the 1970s and 1980s. But early in 1990s the old idea of replacing the pistols in the hands of the troops with some more effective, shoulder fired weapon, rise again in the heads of the US Military. In fact, this idea can be dated back to the US M1 Carbine of 1941, but good ideas never die. So, in the 1994, US Army adopted the Colt Model 720 selective-fire carbine (basically, a shortened M16A2 rifle), as the US M4 Carbine. This weapon was intended to replace in service some M9 pistols, as well as some aged M3A1 Submachine guns and some M16A2 rifles. New weapon was much more handy and comfortable to carry, than the long M16A2 rifle, so the US Special Operations Command (SOCOM) put its eye on the M4 as a possible universal weapon for all Special Operations community. For this purpose M4 was latter modified with the M16A3-style flat-top receiver with integral Picatinny-type accessory rail instead of the M16A2/M4-type integral carrying handle. This modificatin retained the M4 index. The only difference between the M4A1 and M4 is that its trigger unit of M4A1 is modified to fire full-auto instead of the three shots bursts in M4. Specially for the SOCOM M4A1s US Naval Surface Warfare Center developed a M4 SOPMOD kit, that consisted of the M4A1 carbine equipped with Rail Interface System (RIS) instead of the standard handguards. The kit also includes a variety of the add-on goodies, such as various sights (ACOG 4X telescopic, ACOG Reflex red-dot, detachable back-up open sights), laser pointers (visible and infra-red), detachable sound suppressor (silencer), modified M203 40mm grenade launcher (with shortened barrel and improved sights). The kit also included a detachable front grip and tactical light.
From the first sight, the M4A1 SOPMOD is an ideal Special Operations weapon - handy, flexible, with good firepower. But the latest experience in the Afghanistan showed that the M4 has some flaws. First of all, the shorter barrel commands the lower bullet velocities, and this significantly decreased the effective range of the 5.56mm bullet. Second, the M4 barrel and the forend rapidly overheats. Third, the shortened barrel resulted in the shortened gas system, which works under greater pressures, than in M16A2 rifle. This increases the rate of fire and produces more stress on the moving parts, decreasing the reliability. While adequate as a Personal Defense Weapon for the non-infantry troops (vehicle crews, clerks, staff officers etc), M4A1 is, by some accounts, less than ideal for the Special Operations troops, at least in its present state. The idea of the complete re-arming of the US Army with the M4 as a money-saving measure, also is somewhat dubious.
Technical description.
The M4 carbine differs from the M16A2 rifle only by having a shorter barrel and a telescoped, 4-position buttstock. The M4A1 is a similar modification of the M16A3 rifle, so for general technical description please refer to the M16 article on this site.
Source from http://world.guns.ru/assault/as17-e.htm

Introduction
I decided to buy a rifle that shoots well at automatic and semi as well. Before I bought this AEG my only ‘all-rounder’ was an MP5A2, and it was just a submachine gun. I decided to buy an assault rifle that is still an ‘all-rounder’ and capable of shooting well over 120 ft. At first I was leaning to the Jing Gong AK-47 Tactical, but later on the forums I found the D-boys M4A1 Full Metal. After reading two reviews about it I decided to buy into the American dream, exactly the time when an airsoft gun shop knocked off 10% of its price.

First Impression
When I got the package home, I decided to open the package immediately. At first, you would not be expecting its package to be beautiful, as the cover doesn’t have any colors on it except black and brown. After opening the package I set upon my eyes on the little workhorse from China.
The first thing I noticed about this MPEG is the heft. The gun clocked at 3.2 kg unloaded, and nearly 4 kg loaded! This is really a nice bonus to this company and the gun as well.
First Impressions: 10/10

The box
The box isn’t the most beautiful package of all. I’ve seen Tokyo Marui packages, ICS packages and Jing Gong packages and they are all more colourful and more beautiful than the D-boys M4A1 box. However, it does its job, and I’ve seen from other reviews that the box package is better than the previous D-boys MPEGs’ packages before, so this company is really moving forward in packaging. Still I wasn’t buying the box, so I continued to take a look at all the toys inside this box.
It comes with a small pack of BBs, a cleaning rod, a sling mount, a tactical three-point sling (very good quality), an allen wrench, a phillip screw, a manual, and the gun (of course).
The box: 9.5/10 (The box is just black and brown, compared to what boxes from Jing Gong/Echo 1 are like)

The gun
Externals
Note the mark of “Metal” and “ABS” in this section
Barrel
[IMG]E:\D-boys Bi 3681 M4A1\_0006.JPG[/IMG]
The barrel is one-piece. The inner barrel is made out of brass. At least it’s better than some Chinese airsoft companies that uses aluminium barrel. It does its job alright.
(Metal)
Handguard
[IMG]E:\D-boys Bi 3681 M4A1\_0003.JPG[/IMG]
The handguard does its job as well. It is the place where you store a battery in. There is nothing very distinctive inside, so I assume it’s pretty much the same as other companies’ Armarlites.
(ABS)
Receiver
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The receiver is also good as the photos you see on the web. However, there is a 1mm gap between the lower and the upper receiver. You may need to use 15lbs of pressure to close it. You can see the gearbox from this gap. It is a type 2 gearbox.
One note worth mentioning, the receiver is blank, so you can cut out whatever company trademarks you like on it.
(Metal)
Charging Handle
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The charging handle is moveable. You pull it so the dust cover pops out, to reveal the hop-up adjustment, as well as the front of the gearbox.
(Metal)
Magwell
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The magwell is the only bad part on this gun at this stage. The magwell is loose and my magazines wobble in it. You can use some small pads to remedy this problem. It is also fussy on magazines. You can only use D-boys hi-cap magazines, the STAR real-cap magazines, the G&P magazines e.t.c..I am not sure if the Classic Army and King Arms magazines fit as well. It will NOT fit a JG and Marui magazines.
(Metal)
Magazine
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The magazine is a high capacity one. D-BOYS decided to inscribe their name and logos on the bottom of the magazine. It holds 300 rounds and is of better quality then the A&K and Jing Gong magazine (I think). However it wobbles in the magwell as mentioned earlier. You can buy G&P and Classic Army magazines, but they cost twice as much as these. Newer D-BOYS magazine have Heckler & Koch Law Enforcement trademarks on the side of the magazine.
Pistol grip
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The pistol grip on this gun is quite well made, it has a slightly reflective finish. It also has a nice texture to it, and is quite comfortable to hold. Here you can see one of the D-boys external flaw: visible seam lines and moulding marks
(ABS)
Stock
[IMG]E:\D-boys M4A1 BI-3681M Full Metal\_0009.JPG[/IMG]
The stock on the m4a1 carbine is a nice, 6 position L.E style retractable stock.
It is one of the most complex externals of this rifle. It is slightly reflective. Only the outer stock is made of ABS, because the buffer tube, and the adjustment button are made of metal. The stock wobbles slightly, so if you don’t want to make too much noise as a sniper, then you should put two to three layers of tape on it to remedy this problem. As for me when playing airsoft, I am a riflesman, so I don’t need to perform this. After trying all the positions, I found that the 4th position is the most comfortable. It has a nice black coloring, but is slightly reflective. It is composed of plastic, with the buffer tube and rear sling loop being metal. I have tried it in all the positions, yet I find the 3rd the most comfortable but that’s a personal preference.
Note: If you are wondering what that black thing is around the stock, it is a sling mount that is more comfortable than the stock rear sling mount.
Sling mounts
The forward sling mount is very annoying, it is very noisy and rattles whenever I move. The front sling mount is removed from my gun already. The rear sling mount is much better. It sits well, and doesn’t rattle. My forward sling mount has been replaced by a new unit, but it still remains in my package just in case I lose the new unit.
(Metal)
Sights
The sights of this gun is good, but not great. The first aperture has a wide hole, so when aiming, you put the front sight post somewhere in the middle by guesswork. The second aperture is a small hole which is very hard to focus properly. This is not a fault of D-boys (even Systema has this fault). Anybody who uses a real AR-15 series would know why. Sights on an H&K gun is of course a different story.
Trademarks
There are no trademarks on this gun. No “Made in China” and no “D-boys/BOYI” on the gun, but there is one CA (The A is modeled strangely) trademark on this gun. The “CA” trademark doesn’t mean anything on this gun, but from my guesswork I think it might probably be that this model is a clone of Classic Army M15 models. There is BOYI warning sticker, if that counts as a trademark. But the internals seemed more of a G&P clone instead of a Classic Army clone. More on that later.
Overall
Overall, the external of this gun is excellent for the clones made by Chinses MPEGs. In fact, I am very impressed by the externals of this gun. I have messed around with Tokyo Marui FAMAS SV and Classic Army MP5A2 and noticed their exceptional external qualities, but D-boys had already blew them out of the water on this.
Externals: 9/10 (The built quality is very good, but seam lines and mould marks are very visible)

Internals
Inner barrel
Let’s start with the inner barrel. The inner barrel is a 363mm +/- 5mm in length, and is the standard 6.08mm inner barrel. The barrel sends the bullets out decently, but not as good as some after-market ones.
Gearbox shell
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This is one of the internals that only one Chinese company, D-boys did up to 2008. D-boys was the pioneer of Chinese company who really reinforced the gearbox shell on the front instead of the back, where the most stressed parts are at the front, not at the back. Even for high-end companies, not much of them reinforced the forward part of the gearbox. It seems that only STAR, G&P and Systema have reinforced their forward part of the gearbox. By now, A&K (another Chinese company) have also copied what D-boys did and reinforced their forward part of their gearbox. The D-boys gearbox shell was one of the few internals parts I have praised.
Motor
The motor is a Chaoli type or something like that. It has good torque, but auto fire sounds strained and is fairly whiney.
Gears
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The gears are standard XYT gears, which stuck up all the way to the D-boys SCAR. The gears spin well, but there was a factor causing a flaw on the spinning of the gears. The gears are praised for being full metal and can stand up to about 420 fps, so when I opened up the gearbox, I found out it was true, so it was indeed an excellent job done on the gears.
Shimmings
I’ve got to get this thing straight. The shimmings are utterly crap. D-boys thought that almost .7mm of slack on both the bevel and spur gears would be excellent. It is the worst shimming I’ve ever seen on all the other guns I have taken down before. A re-shim job is definitely needed if you want to upgrade this gun.
Spring
The spring was equivalent to an M110. The spring was short and very stiff. It was not one of the best part of the internals of this gun, so if you want to modify your gun into a more accurate weapon, change it to an M120 spring.
Cylinder
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The cylinder of this gun is one of the good parts in the gearbox compared to other parts in this gearbox. The compression was another story. It is horrible. The cylinder head is okay, but if you want it to be better, swap for an after-market one.
Piston
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The piston is fairly decent but not the best. There are no teeth breakages, so let’s hope this record keeps up. The o-ring lets it down in this category. I started leaking air after nine months of use.
Air Nozzle and Tappet Plate
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The air nozzle was a clear grey. I have detected no air leaks on it so it‘s pretty tightly sealed. Let’s hope that it lasts a long time!
The tappet plate was made out of very hard ABS. It sounds convincing that it won’t break easily.
Spring Guide
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The spring guide is another nice feature in the gearbox. D-boys placed two slick washers on top of each other instead of spending more cash on a ball-bearing version which really works efficiently. The shaft is plastic while the base is metal.
Hop up
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Finally, the hop-up. The hop up adjustment is utterly crap as well. As soon as the pellet went over 120 feet, it either turns left or right, sometimes it even takes a dive-bomb before 60 feet.
Battery
The battery is a 8.4v 1100maH one. It is an average battery, which does its work but you’re not going to expect the rate of fire of this gun to go over 15 RPS with this battery. This battery is already a back-up one by now, as I have bought the Intellect 8.4v 1600maH battery for my primary use.
Internals: 7/10 (Shimmings are horrible, motor is slow, the wiring is thin and the hop-up is utterly crap, but the other parts are very good)

Disassembly
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First, disconnect the plugs connecting the battery and the gearbox, and take the battery out as well.
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Now un-screw the two srews using an allen wrench and pivot the pins out on the same side. Then the receivers can be slid apart carefully.
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The hop-up unit and the barrel resides in the upper receiver.
[IMG]E:\D-boys M4A1 BI-3681M Full Metal\D-boys M4A1 Disassembly steps\_0135.JPG[/IMG]
The gearbox residing on the lower receiver
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Now, to take the gearbox out, first remove the bottom plate of the pistol grip, and take the motor out. Now un-screw the two screws at the bottom of the pistol grip, and then remove the pistol grip carefully.
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Then take the stock out from the tube, and then unscrew the butt stock as well. You may need a flashlight as well to unscrew the stock tube from the receiver.
[IMG]E:\D-boys M4A1 BI-3681M Full Metal\D-boys M4A1 Disassembly steps\_0128.JPG[/IMG]
Then remove the magazine catch button simply by un-screwing the screw in the middle of the button. Take the button out along with the spring.
[IMG]E:\D-boys M4A1 BI-3681M Full Metal\D-boys M4A1 Disassembly steps\_0130.JPG[/IMG]
The last step is to pivot the pin out on the left side of the receiver ONLY. By now, with a little force, the gearbox can be taken out from the receiver.
To disassemble the gearbox, just un-screw all the screws on the surface of the gearbox and then take the shell off with a flat-headed screwdriver.
To reassemble this gun, just perform these steps in reverse.

Upgrade
D-boys is known for its full metal external and internals. Although they lied about metal bushings, the gun in fact has a great amount of upgrade spaces, unlike Jing Gong M4A1s.
D-boys decided to copy both Classic Army and G&P instead of copying Tokyo Marui, which was what JG did, so internals from D-boys are usually able to swap for a G&P and Classic Army internals, especially if you don’t want to spend extra cash on the Systema ones but still retaining the reliability of Systema. Second, Classic Army’s internals will also fit on the D-boys M4, although the price would be slightly more expensive then G&P’s internals. If you want your gun to outperform any other guns in your team, Systema internals would be best for you. They are more expensive then both Classic Army and G&P but would turn your gun from a second rate engager into a top-notch shooter. To me, I prefer to use G&P internals because of its price, quality and reliability. D-boys’ gearbox is able to withstand all those challenges as well as springs from M100 to M130. However, words to wise, use good quality ones, DO NOT buy Jing Gong or A&K ones as you will regret buying them in my opinion.
My recommendations is, use Systema if you want to be a top-notch shooter, and use G&P if you can’t spend those extra cash but still retaining its accuracy and reliability that is on par with Systema.
However, if you don’t like to waste too much cash, I recommend you to use the better internals on this gun only, while retaining the stock gearbox shell because you may not know if those companies’ gearbox shells fits on this gun or not.
For motors, you may use motors from G&P, Classic Army, Guarder, King Arms and Systema. My recommendations is to use high torque or super torque motors as it would give a high rate of fire without wearing the gears so quickly.
For batteries, those from G&P, Classic Army, Excel and Intellect are good ones. So long as your gun isn’t using batteries more than 9.6v, it would last you a long time. I recommend Excel and Intellect batteries, they are all better made than G&P and Classic Army.
The hop-up rubber is very important for an airsoft gun. That’s why choosing a good quality and effective one is very important, without this unit, your airsoft gun cannot fire up to 75 feet away. That’s why, choosing excellent hop-up unit is very important. Systema, Guarder and G&P makes good hop-up rubber. I recommend the Guarder’s hop-up rubber as it is not as expensive as the Systema’s and still retains the performance of a Systema hop-up rubber. For the piston and the cylinder, those from G&P, Classic Army, Guarder and Systema are very good. I recommend Systema and Guarder’s piston and cylinder, as both of them are of very good quality.
For the gears, G&P, King Arms, Systema and Guarder are all recommended for upgrades.
That’s all for upgrading internals.
For externals, you can start first by upgrading the stock. You can choose the M16 fixed stock and the special fore crane stock for large battery. You can use a SOPMOD stock or the Magpul CTR one as well.
For the grip, you can choose the Magpul MIAD, or sniper grips as well.
For the handguard, you may use the SOPMOD type or the CASV, but both handguard cannot store the battery inside, which means you need either the crane stock or the M16 fixed stock or you may have to use a battery box outside the gun. I would recommend buying the G&G Battery Magazine
If you wanted a handguard with rails that can also stow the battery inside, I can only recommend the S-system one.
For sights, you may use flip sights and fixed sight.
To me, I would like to keep the stock gun as original as possible on the externals.

Additional Information
Trademarked-metal bodies
Here is a list of trademarked-metal bodies (all from D-boys) for your gun. (Source from Gunner Airsoft). D-boys have recently started coming out with guns with the real-steel trademarks on them. They will be noted by the product name of BI-#### - DX. The trademarks are advertised to be laser-graved.
Noveske Scorpion
Marine Crossbone
Troy SR-16
Bushmaster SR-25
Delta Force Transformers
FN Herstal Air Force
Colt
The most popularly-seen trademarks are Colt and Marine.
My own weapon upgrade
I have upgraded and modified my gun with the following:
Externals
My advice is to keep as much externals as stock as possible. However, the thought of making it a better weapon overwhelmed me, so I modified the rifle using the following:
Magazine
I bought a Magpul 5.56 NATO Standard 3 Pack for three of my D-boys magazine. They make the reloading much faster than without them. However, this is not necessary for modifications.
Carry handle rail
I have also added a carry handle rail so that I can add a scope on top of the handle to clear the front sight, which helped a lot in making this weapon into a compact sniper rifle.
Telescopic Scope
I have added the Bushnell 3-9x scope to convert my carbine into a compact sniper rifle. It really helped a lot in several airsoft fights in the woodlands.
Internals
The internals should be what you need to upgrade and modify. I have almost modified the entire gearbox. Here are the things I have upgraded:
Hop-up unit
I recently swapped the stock one for a Guarder hop-up unit. The effective range of this gun shot up dramatically after this modification. I would recommend both Guarder and Systema hp-up unit and rubbers, as they are all cheaper than Firefly and Prometheus but retaining the same effectiveness.
Inner Barrel
To make my weapon into a compact sniper rifle, I swapped the stock barrel for a Prometheus 6.03mm tightbore barrel. It improved my weapon’s range and accuracy, switching the weapon’s effective range to around 180 feet away. Impressive.
Cylinder Set
A Classic Army cylinder set was swapped for my carbine. It was great, and it worked really well with no issues for a year already. Let’s hope this record keeps up.
Piston
The stock piston was swapped for a Classic Army reinforced one together with the o-ring. Now the weapon has a greater air-seal and no leakages anymore. The power shot up to about 340 fps until I changed the barrel and the hop-up unit, the power then dropped to about 300 fps.
Motor
A G&P high torque motor replaced the stock one just three months ago. The gun now shoots at 15-17 RPS with the new motor, and the distinct whine that “accompanied” with the stock motor was also gone.
Shim set
The shimmings of the D-boys M4A1 was horrible, so I swapped for a Classic Army shim set. Now the gears spin like how it should have.
Other upgrades
I have bought an Intellect 8.4v 1600 maH battery for my weapon so that the RPM/RPS would be faster. Now the gun shoots at about 15 RPS/900 RPM with other things all stock.
Future upgrades
Externals
I would like to change for a new handguard, which I think G&P is the best out of all the others. Also, I would like to change for a new front and carrying handle, which I think the G&P one is the best.
Internals
A new set of high torque gear from Classic Army would be a good idea to make my gun shoot better. A new tappet plate and a new air nozzle from either G&P and Classc Army would be also a good choice to upgrade. These three options would start to kick-off when my gun finally breaks down. The wiring would also be swapped for a new set by Guarder sooner or later.
Shooting report
As usual, after three months of testing, I’ve got to do a chrono test.
(All test done with KSC 0.2g BBs, using D-boys high capacity magazines)
Range and accuracy test
Test 1
(This test is using Guarder hop up unit, Prometheus 6.03mm tightbore barrel and M100 spring. KSC 0.25g BBs are used in this test)
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15 yards
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30 yards
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45 yards
Test 2
(This test is using Guarder hop-up unit, Prometheus 6.03mm tightbore barrel and an M100 spring. KSC 0.2g BBs are used in this test. )
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15 yards
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30 yards
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45 yards
Overall the gun is pretty accurate within the range of 150 feet. Accuracy is acceptable at 180 feet or over. (Both with Guarder hop-up).
Power test
[IMG]E:\Bi 3681\_0003.JPG[/IMG]
As this gun states at a power of 1.1 joules with 0.2g BBs, this roughly translates to 320 fps using 02g BBs, and about 280 fps with 0.25g BBs. With 0.2g BBs, It was able to penetrate one side of a can, and dented the other side, not too seriously. It is just ok for a beginner like me, but to experienced shooters, you may like it to be a bit more powerful.
I have been using an M100 spring, a Guarder hop-up unit and a Prometheus tightbore barrel. All these factors contribute to the fps being downgraded. My gun now shoots at only 300 fps but had a maximum range of 180 feet, compared to the stock one with 320 fps and a maximum range of about 120 feet.
Power: 9.5/10 (Good enough for me, but not good enough for snipering)

Skirmish Report
It was my first skirmish to use this weapon. We were in a 12 to 12 match, and our objective is to kill the entire opposition team before they do the same to us. We chose three sites: the CQB site, the container site and a forest with an abandoned house near the middle.
My team was armed with a Jing Gong M4A1 (upgraded), a G&P M4A1 (upgraded), a Classic Army SCAR CQC (upgraded), two TM M4 S-systems, a TM VSR-11, a UTG L96, a Classic Army M14, an ICS M4A1 (upgraded) and two Classic Army MP5A4s.
The enemy team was armed with three King Arms FAL, two TM VSR-11, two TM M4 S-system, one Kart M14 EBR, two Classic Army M15A4 Carbine, one G&P M249 and one G&P M16A3.
My weapon was already upgraded with a Guarder hop-up unit, a tightbore barrel, a torque-up motor, a new gear set and a new cylinder mentioned above already. As I loaded three of my hi-cap magazines up in the safe zone, I wondered if this gun is still performing rubbish or did it really improve.
(This description was the last match, occurred in a forest with a small house near the middle)
After seven matches, this one would be the hardest out of all. When the whistle was sounded, both sides started the game. My first contact was being a friend with a TM M4-S-system at around 50 feet. He opened on me first but I was in fact hiding behind a fallen trunk. Just as he was reloading I opened fire on him and scored two shots to the chest and one to the head.
‘Pretty good’, I thought, while I was installing my Bushnell telescopic scope, and then moved on. It was about ten minutes later when my friend sighted another enemy troop armed with a King Arms FAL, patrolling around the small house. It was about 75 feet, so I had to take a careful aiming to hit him. I hid behind a tree as he turned away from me. I took careful aim at him and took him out with a shot to his head.
My squad then made it to the house, and two of our squad members went inside to search for targets. At this moment I sighted another enemy troop armed with a G&P M249 PARA at about 170 feet away. We both knew that we were out of our effective range so we both waited for one another to make a mistake. He was the first to open fire, but his rounds hit the roof of the house instead. I then crawled to a good position with several rocks acting as cover, took aim, and let out three short bursts aimed at a head length above his head. One of the bursts caught him around his groin. My mates then came charging out of the building, confused by the shots as if they were surrounded. We found no more targets and we reached the enemy base and killed two enemy troops there with several short bursts. The skirmish ended up as our side’s victory.
Back at the safe zone people were curious about why my MPEG was able to shoot so far away and how is the power of the gun. We set up a target, 1” x 1”, at 180 feet and my gun managed to hit the target five times out of fifteen shots (using my trusty Bushnell scope, of course). I was able to hit a target 9 times out of ten at 120 feet, twice a bullseye (again, using my trusty Bushnell scope, of course).
Using a chrono, we found out that the weapon is about 300 fps after upgrades, but this made the BBs sail straighter then with my stock barrel.
Overall I was very happy with this gun on that day, being able to kill at least twelve enemy troops while being killed only twice (both times in the CQB scenario).
Performance: 9/10 (the magazine wobbles and sometimes misfeeds)

Evaluation
Appearance: 5/5 (A very nice looking gun straight out of the box)
Realism: 3/5 (No trademarks, but everything else is replicated nicely except the bolt and no “Made in China” marking)
4.5/5 (For the new version. No “Made in China” marking, all Colt markings are nicely reproduced)
Quality: 4/5 (The grip lets it down because of the very visible seam lines, the stock also lets it down by a bit. That’s why I upgraded this weapon with a Classic Army motor)
Power: 4/5 (At 320 fps, it is good enough already, though it wouldn’t be good for a sniper)
Accuracy: 3/5 (The accuracy is just mediocre. That’s the reason I have upgraded this gun with a Systema hop-up and a Systema 6.03mm tightbore barrel)
Value for money: 5/5 (As a gun which can be upgraded with tones of accessories to make it as good as other high end guns but still cheaper than a high end gun after upgrades)
Upgrade Potential: 4/5 (It can only use G&P, Classic Army, King Arms and Systema accessories, Marui and ICS accessories will NOT fit in this gun, which brings this category down a bit. Still there are tons of accessories for this gun to be upgraded)
Overall Potential: 5/5 (This weapon could be a good machine gun in stock form, and can be a very good precision firearm after upgrading. With tons of accessories for this gun to be upgraded, It can be turned out to be a very good gun with its price still cheaper than other high end guns)
Overall: 8.4/10 (With a bit of tinkering and trials, you would be able to make it into a perfect gun)

Pros and Cons Evaluation
For those people who didn’t even bother to read the review, here’s a short sum-up.
Things that I don't like
Stock wobbles (can be easily remedied) (semi-con)
Magwell is too wide and magazine wobbles in it (can be easily remedied) (semi-con)
Stock shimming is horrible
Mediocre accuracy
Motor is not too good to provide a fast rounds per minute the M4A1 should have
Plastic bushings instead of metal or bearing bushings (semi-con)
Visible seam lines and moulding marks (semi-con)
No mock bolt (what a shame!!!)
Blank receiver (you can add whatever trademarks on them as you like) (semi-con)
Bolt catch is brittle
Disassembling the gun is a PITA!!!
Things that are sweet
Many modification could be upgraded, including gearbox, motor, handguard, gears e.t.c.
One piece outer barrel
Full Metal
Decent weight for a decent gun
7mm reinforced gearbox
Brass inner barrel
The external quality is very good
At least quieter then other clone guns made by China
Good power
Decent price for this gun
Hop-up is very easy to adjust with no mock bolt
Decent battery and charger provided
Decent sights

Recommendations:
If you like to use this gun in stock form for at least three years, I would not recommend this gun. If you wanted a gun that is cheap and accurate in its stock form, I won’t recommend this gun to you as well. The Jing Gong/Echo 1 series just fills in for this purpose.
However, if you are a newbie to airsoft and you don’t mind spending some cash on this gun when there are some problems, I would recommend this gun to you. I too would recommend this gun to you if you love tinkering, modernizing and upgrading your gun to a higher level (people like me).
Conclusion

I’ve used many high end guns before (STAR M4A1, G&P M4A1, Classic Army FN SCAR C.Q.C. e.t.c.), but they would not replace my D-boys M4A1. For just $130 to get an okay accurate and a full metal gun, it is great. It is an outstanding clone, at some points even better than the Jing Gong M4A1. It is not too powerful for CQB and powerful enough for woodland. There is nothing on this gun that needs immediate attention. It will last at least four to five years. Of course, like all clones, they are not as good as Guarder or Systema: fix these bad parts parts, or swap for better internals (better gearbox, motors, hop-up, inner barrel e.t.c.), then you would be holding a Chinese airsoft gun that is better then Tokyo Marui and as good as ICS Armarlites or even G&P Armarlites.
More pictures
[IMG]E:\D-boys M4A1 BI-3681M Full Metal\_0005.JPG[/IMG]
The box design is simple, right?
[IMG]C:\Documents and Settings\user\My Documents\My Pictures\D-boys M4A1 Box with cover.JPG[/IMG]
Inside the cover
[IMG]C:\Documents and Settings\user\My Documents\My Pictures\D-boys M4A1 inside box.JPG[/IMG]
My gun in the box

My weapon over my camouflage BDUs.
[IMG]E:\D-boys M4A1 BI-3681M Full Metal\g.JPG[/IMG]
My M4A1 in CQB Configuration
[IMG]E:\D-boys M4A1 BI-3681M Full Metal\0.JPG[/IMG]
MY M4A1 in Sniper Configuration
[IMG]E:\D-boys M4A1 BI-3681M Full Metal\t.JPG[/IMG]
My M4A1 in Standard Configuration (Bushnell scope for looks only in this photo)

[aZn_triXta07]

Host your photos on a server such as imageshack or photobucket before you link your pics :P

[Muffin]

Reviews belong in the 'reviews' section.

[Cilantro]

Originally Posted by Muffin

Reviews belong in the 'reviews' section.

+1, but as for the review itself you did a great job, covered all the info and then some, but I'd love to see your pictures working. Reviews are so much better with purty pictures.

[Mitchell12]

We don't have your hard drive. Host on www.imageshack.us

[tycho]

Good review - funny linking to e: for photos :P

And also, as has been mentioned, there is an entire forum called "Reviews" :|