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Old November 20th, 2008, 21:48   #1
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Kwa km4a1 indepth review

KWA KM4A1 Carbine

The looks and feel of this gun are outstanding, the entire gun is jet black giving it a mean look. When I first removed it from the box it came in I was amazed at the feel of this gun. After previously handling a JG M4, the weight of mine felt balanced in the center of the gun making it very easy to maneuver around my body. Although a plastic stock and hand guard the gun had a very solid feel and felt no wobble what so ever.
The design of the KWA one piece adjustable outer barrel made the whole solid feel and totally eliminated barrel wobble. After feeling the barrel and pushing on it I knew it wasn’t going anywhere. In comparison to a JG M4, the barrel wobbled significantly, +/- 2-4mm either way for the JG's. The hand guard on my M4 didn’t move and still doesn’t after some wear and tear.
The 6 position LE stock, although plastic like its real steel counterpart, is very sturdy and doesn’t move at all once locked into place. The stock tube is well mounted to the receiver of the gun and along with the barrel isn’t going anywhere over time.
The pistol grip is plastic on the KM4 just like other M4's and is very sturdy, but to separate it from the group, it has a heat sink on the bottom of it. The heat sink allows the gun to be fired over long periods of time without the engine overheating or burning it’s self out.
The metal charging handle wobbles a tad bit, but unnoticeable until pointed out. The charging handle cleaning pulls back and reveals the hop-up adjustment. The smoothness of the charging handle should be noted when pulling it back, on JG’s the charging handle catches until worn in a bit, probably due to bad manufacturing Im guessing.
The selector switch is very smooth and makes a very audible “CLICK” when pushed into place. On other guns after periods of time from moving back and forth this part of the gun gets worn in and lose, but after repeated work it shows no signs of that nice click going away.
When putting the magazine in the gun makes a very satisfy click letting you know that the magazine is in. Other say that the magazine wobbles, mine does, but not very noticeable when playing, if this does annoy you a solution is to but electrical tape around your magazine to prevent it. The magazine release it not stiff but springs back after pushed.
The trigger is very sturdy, but apparently the trigger block breaks after repeated semi-auto use. After putting it through the paces, my trigger block has stood up to the test of time and in conclusion, unless you have a lead finger, will not break.
The delta ring at first is VERY stiff and might need two people to help you put the hand guard back together, but after time, it does get very easy to deal with yourself.
The carry handle is very sturdy although plastic. I find myself carrying my gun around by it without a distant though of it breaking. The sight adjustment is very nice and precise, it makes a loud click when turned which is helpful when compensating for windage and elevation. Along with the carry handle, the sling attachments are very durable and I would trust hanging my gun off of them, all the sling attachments are metal, including the one on your stock.
That concludes this portion of the review, if I still haven’t got you running out and buying one yet then I don’t know what your looking for, maybe the part two, the performance review.

The gun performed very nicely when I first shot it, even today. Contrary to popular belief the KWA M4 is accurate, but only when fired semi-automatic. I found when firing full-automatic the gun sprays quite significantly.
I could hit a thin tree every shot from about 75 feet effectively. At 100 feet the tree became a bit difficult to hit, but still manageable. At 150 feet a man sized target was very difficult to hit, but possible under right conditions. At 200 feet, I wish you luck touching someone from that far, the effectivity of the gun stock renders it incapable to hit that far, but the potential is there to upgrade the inner barrel and bucking to reach it.
The hop-up is fairly consistent, seeing that the stock bucking isn’t the best. The gun had no problem as curving left and right, maybe +/- 1 foot when at 100 feet shooting. The sights are very easy to use on the M4 and there are two apertures, small for accurate long range shooting, and large for full-automatic shooting. As I said before, “The sight adjustment is very nice and precise, it makes a loud click when turned which is helpful when compensating for windage and elevation”. The front sight is also adjustable, but you can only raise and lower the front sight pin.
The Rate of Fire (ROF) of the gun was pleasing, it can lug back a M120 spring and get 12-14 Balls Per Second (BPS) with a 8.4v 1100mAH battery. I have yet to test it with a 9.6v or a 11.1v Li-Po battery but the official ROF with a 11.1v from KWA is ~20BPS. The battery connectors are small Tamiya connectors, the gun will take other batteries with other small female Tamiya connectors unless you change it to deans to get a extra boost in ROF and trigger response.
At the chrono, my gun at first was getting 410 Feet Per Second (FPS), after the M120 spring had settled I was getting 395FPS +/- 3-5FPS.
The battery compartment is very small on the gun, just like other M4's, I would suggest a Li-Po, 7.4v or 11.1v, depends on how much ROF you want and how long you want your gun to last for. The Hi-Cap magazine works beautifully with any jamming or malfunctions, the winding for it is crisp and easy and feeds like a charm.
To sum up the performance of the gun into on word, it would have to chose the word “phenomenal”, the gun is very consistent with FPS, BPS and accuracy. There is potential for a more accurate gun if you chose the right combination of tight bore inner barrels, hop-up buckings and hop-up nubs.

The internals of the gun are very comparable to a Systema, if not better. The gun comes STOCK with a M120 spring, a very strong motor, a superb gear set, a polycarb piston, aluminum unported piston head, reinforced version 2 gearbox, 2 piece plastic hop-up chamber.
The gears on the gun are very impressive. The process of making the gears are so precise that the gears do not require shims, they fit perfectly into the gearbox, but only the KWA gearbox. The sector gear of the gearset speaks loads about KWA’s intelligence in gun making. The sector gear comes stock with a sector chip (a small piece of metal on the sector gear that keeps the tappet plate open longer to prevent miss-feeds at high ROF setups like the KWA KM4A1 or KM16). The sector gear is also thicker than normal ones, this allows the gearset to take more stress from the high ROF setup. The other gears are normal upon examinations. The gears are precise and do not need re-shimming or shimming at all to be exact. The bearings consist of 8mm and 9mm metal ball bearings, these provide very smooth movement of the gears, the smoothest I have ever seen.
The polycarb piston head is probably the strongest, lightest and best engineered piston I have ever set eyes on. If I were to upgrade any gun to a highspeed or even a high torque setup, this piston is a must have. The piston head is aluminum, unported. I have no clue why it isn’t ported, but then again, KWA had their reasons probably.
The reinforced gearbox is jet black and outstanding, the front of the gearbox has a extra screw in it to hold it together during the high stress of the guns ROF and spring. The air nozzle is different from others and is unique to the KWA, after market parts won’t work, but this part has no need to be replaced.
The piston head and spring guide are metal, but are claimed to have “bearings”. After a closer examination of this, the “bearings” appear to be washers placed on top of each other. I have no clue why KWA “cheaped” out on this part of the gun, although it should be looked over and revised in the next 2009 version of the KWA KM4A1 and KM16. These parts are the only parts inside the gearbox that needs to be replaced to ensure a long lasting high ROF setup.
The two piece plastic hop-up provides a very good air seal resulting in the guns consistent FPS. The bucking and/or nub should be replaced on this gun in order to get a more reliable, consistent setup for increased accuracy at greater distances.
Other establishments have test this gun and put it to extreme conditions, I will quote them in this paragraph. I have not tested my gun to the extreme since this is my only KWA KM4A1 and I would be devastated if I broke it in the name of science. Special thanks to Airsoft GI for providing this information on their website for me to use.
“We decided to test their efforts with an 11.1V 3200MaH Li-Po battery; it held up great at 400 FPS with a fantastic rate of fire. After putting out a few thousand rounds with that battery we decided that it was time to really test the internals with a 16V Li-Po. This battery has never been used in a gun longer than a few seconds because it keeps breaking pistons; even our fully customized Airsoft GI High Speed P90 only pulled off one BB before the gears stripped and the back end of the piston ripped off. To our surprise the KWA M4A1 was able to successfully empty 8 high capacity magazines without breaking. I should note that the BBs were completely ineffective, they were only traveling at about 150 FPS. There are two possible explanations for this; as the BBs are traveling through the barrel they may be colliding with one another, or the battery is spinning the gears so fast that it is catching the piston on its way forward in which case there would be incomplete compression inside the cylinder. Either way, we concluded that the 16V Li-Po is useless with this gun, but it’s amazing that the gearbox can handle such abuse and still be in tact and operational. This display of durability left us speechless, we were extremely curious to get inside the gearbox and see what KWA had done, so we got right to work.” -
The spring guide, another innovation by KWA, they put a version 3 spring guide into a version two gearbox because version 3 spring guides have a wider base than a V2, so it can handle more stress!

AFTER 85,000 ROUNDS!!!!(Courtesy of KarMeister from KWA Forums)
Finally took it apart after around 85,000 rounds with 11.1 Lipo 15c

What i found out:

Check on parts:

Switch assembly: I was surprised to see it intact! not burned by the 11.1 lipo! I have seen TM and CA trigger switches burned by just 9.6v subc!

Piston Body: Regular wear from high ROF. 1/3rd of teeth peeled off from catching the gears.

Gears : Shimless! After stripping the grease out with gasoline, the gears look like theyre brand new! No wear at all! (thers this crack on my sectr gear's "shim"? near the axle but It looks like it was a factory defect but it doesnt affect the gears or performace.

*The gears have the normal TM/ICS/CA ratio

Bearing Bushings: Looks new! feels new!

Piston Head: I see a few small dents on it. cleaning/relubing the cylinder and cyl head should do it. Was a bit dissapointed to see washers instead of bearings. Replaced the washers with a guarder bearing set i had lying around.

Spring guide: Version 3 on a version 2 gearbox? hehehe! Like the Piston head It uses 3 washers. not bearings.

Cylinder : It is firmly attched to the head and very hard to take off! I dint take it off so i wouldnt mess with the compression.

Gearbox: We all know that its thick on the front. Great design even from the inside! I noticed a part added to hold the wire down near the bevel gear! great innovation! Im sure the guy who designed it had the same problem i had! (the wire caught the pinion gear so i coudnt take the motor off!)
The gearbox has an interlocking design that makes it a strong
solid piece.

Note: The Piston body can still take some pounding but can stand to be replaced if i change to an sp130.

In conclusion, KWA has made a outstanding AEG that sits in the record book as the first Li-Po ready AEG. KWA has established their name in the business and to me looks more professional then Systema. KWA has created supreme bragging rights and their products are a must have for any one getting into airsoft or that have had years of experience as I have. This gun is a must have.

Last edited by vic_man4; December 10th, 2008 at 20:39..
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