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Review - ICS M4 BIBLE: Problems and Fixes



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Old July 4th, 2004, 20:36   #1
Join Date: Jul 2003
Review - ICS M4 BIBLE: Problems and Fixes

Ok, I'm buying an ICS M4, and I wanted to research it as much as possible. There's tons of information on both and and it's almost overwhelming. There's a frickin 21 page thread on filairsoft on this. So, I condensed all the useful information that I could find into this one thread so nobody else will have to go through the pain of hunting all this up. This IS NOT MY MATERIAL, but is rather adapted from the experiences of actual ICS M4 owners across the world.

I hope it helps some of you ICS owners out.

ICS Innovations:
- De-cocking lever incorporated on the forward-assist button
- De-cocking is not possible using an ultra or infinite gear because the swing-arm inside the lower gearbox hits the spur gear
- Metal receiver is nicely finished, laser etched markings of Olympic arms
- Pipe stock is different in design, totally different than Marui, even the way it's bolted
- Barrel wobble is non-existent. Totally re-designed from the collar ring to the front barrel
- Internal wiring is neater, with small conduit nicely done towards front of gun
- High capacity magazine
- More robust gears, standard ratio
- The small screw locking the mag release has been changed for the better.
- De-cocking feature is quite useful, but is not possible if you use ultra or infinite gears.
- Just chronoed the barrel with and without the o-ring in front of the hop assembly. FPS went up with that o-ring! ICS got something right!
- Now for the fun part; I had installed an old polycarbonate piston head which separated from the piston after a few shots. Had this been another Marui AEG I would have just put it back in its gun bag and pick up another AEG - imagine having to take of the ret. stock, motor plate, motor, pistol grip, mag catch, hop-up thingy, etc, etc. As this was an ICS M4, I opened the receiver, pull out the upper gearbox, took out six screws, and presto, installed a brand new Prometheus piston head, and had the AEG firing away...all in less than 10 minutes, and at a leisurely pace too.

- Metal receiver is longer than your regular Marui receiver to accommodate the swing-up upper receiver

Pistol Grip:
- Pistol grip is more durable than Marui, more motor space inside; wiring is straightforward, better designed motor plate
- Don't replace the stock pistol grip with Guarder reinforced grips. The angle of the motor will not be aligned properly and it will eventually ruin your bevel gear.
- ICS pistol grip is different size than the Marui pistol grip. Its thinner, I think to make it more realistic than the Marui ones. Even the Marui motor plate does not fit on the ICS pistol grip.

-ICS motor may be louder than a TM motor out of the box. This is due to the fact that the pinion gear is longer on the ICS motor than on the TM motor. It can often be changed back to a normal volume by adjusting the motor height.
-If you are buying an EG1000 or other aftermarket motor for the ICS gun, it is suggested that you swap pinion gears so that the new motor has the ICS pinion on it. This is mainly due to the fact that the ICS one is longer than most out there and it's made that way for a reason. A shorter gear may not mesh as completely with the mechbox gears and result in a stripped gear over time.

- Gearbox is a 2-piece design exclusively made and designed by ICS similar in material to Marui
- Upper gearbox is judging from the reinforcements on the front part, looks more durable than a version 3 gearbox
- Internal dimension where the spring and pistons rest are the same, but inner dimensions lengthwise is about a millimeter shorter
-The most important part of the gearbox (front part where cylinder head rests) has been reinforced like a version 3 box, but a bit thicker.
- Interface integrity of the sector gear and piston gear is excellent and did not present any problem due to the very tight tolerances on the upper receiver-upper gearbox and the lower gearbox
- The piston rails are 'lumpy' in some areas and have to be finely sanded to have better piston sliding.
- It was a breeze upgrading the spring, piston head, and cylinder with the new gearbox design.

Gearbox Screw Problem/Fix:
- The lower gearbox uses 3 screws 2 X 3.0 mm 16 and 1 X 3.0 mm 10. The short screw (3 mm X 10) is not long enough to go through all the threads in the gearbox. Therefore when the gearbox has stress either by upgrading fps or using automatic mode it tends to pull out the threads thus stripping the threads and causing separation at the rear of the gearbox. This could lead to more serious failure as gear stripping and total gearbox failure.
Fortunately for me I didn’t have total failure.
According to the technician ICS is aware of this failure issue.
A good fix and recommended upgrade for ICS CAR-97 M4 owners is to go to your local hobby shop and purchase 3mm X 16 fillister screws (used in RC cars) and cut down the screw so the entire screw goes through the hole located at the top rear of the gearbox. Also allow a bit to come out through the hole to allow you to thread a nut on. Also use locktite blue to further strengthen the threads and nut. This will prevent gearbox failure at the gearbox's weakest point.
As stated before ICS is aware of this issue and they are taking steps to prevent this in future releases but doing the above.

-That problem only existed in the original run of the gun (known as version 1) which was not available in Canada. This is not a problem for any Canadian owners and only existed in guns sold elsewhere in the world. It is now fixed and no guns being produced by ICS should have this problem.

- Don’t use the aluminum piston as it seems to bind too much in the ICS cylinder. The set up I prefer and will field test has the Intruder Shop Poly piston and Systema poly piston head; sounds smoother to me.

- The stock bushings are plastic. Used Systema reinforced bushings. It's hell to install, that's y I used a C-clamp and appropriate spacers to do this. Did not want to hammer it in because this might deform the lower box. Shimming is the easy part, really enjoyed it because of the open design.
- The Systema reinforced bushings are what I can recommend for that gearbox. It is a pain to install because the ICS bushing holes are smaller than 6mm, so it's a pain. Use a C-clamp or maybe a table vise with appropriate adaptors/ spacers to do this. Hammering is not recommended for it will DEFORM the lower box. If this happens, you will have a hard time shimming, not to mention the trueness of the gears is suspect. Then use a lubricant, I recommend using silicon mixed with Teflon treatment.

Anti-Reversal Latch/Spring Release:
- Anti-reverse latch spring is #$@#, it’s so soft, no wonder sometimes the gears would reverse totally if I release the trigger in mid-cycle i.e. spring partially or almost fully compressed. Anyway, I will look for a Marui/Systema replacement today. This may be why your AEG might sometimes shoot out 2 bb’s. Actually, mine would shot out 4-5 bb’s at times when the latch totally failed to engaged.
- The spring release is known to break after a while. I’d replace the ICS anti reversal lever with a Marui or Systema one

- Nozzle for Marui AEG is longer by 0.5-1mm, and tapered thinner at the end. Thus, the ICS nozzle does not seem to go all the way into the chamber of the Systema hop up. It would appear that if you change to a Systema metal hop-up, you will have to change the nozzle too.
- Systema tight nozzle for M4 will be fine

- Area 1000 tappet works fine
- Marui tappet plate works fine

- The ICS hop adjustment is hard to adjust, even when lubricated.
- Install a Systema BS barrel by putting a metal o-ring (instead of the default rubber o-ring - w/c require a groove), it’s the same ring you find on G36 hop ups. You can also buy this metal o-ring thing with an upgraded hop up backing/bucking.
- I installed a Marui stock hop-up on the ICS M4 and the upper gearbox still fit perfectly, implying the Systema metal hop-up can be used - note: use a Marui size nozzle since the ICS nozzle is thinner overall but thick at the lip so it may not seal properly - to my recollection, nozzle length is same for both.
- Also, the bottom tube (connecting to the magazine lip) of the Systema hop-up has to be modified as its flat metal plate snags on the lower receiver.

Inner Barrel:
- Removed the barrel last night and compared it to the Marui. One thing nice about the ICS barrel is it also has an O-ring that seals the barrel outside surface to the hop-up. I install the Marui barrel to see if it would fit and it does but the O-ring feature would be deleted. I need to get a micrometer to check the inside barrel dimension of the ICS because it may be a 1/2 hair wider internally. I rolled a bb through it and compared this test with the Marui.
- ICS inner barrel looks lousy (not sure how other ICS barrels look), the hole for hop-up is unevenly done, barrel finish is very rough - which is probably why it’s disappointingly inaccurate out of the box
- Also, be careful re-inserting the inner barrel into the receiver/barrel. If spring on the hop up is twisted, the gearbox will not fit snugly and you cannot close the receiver.
- Played with the M4A1 using the TN 6.04 barrel....big difference. The range and accuracy was much better

RIS Options:
- The Marui RIS for M4RIS or SR 16 works fine on the ICS barrel - with TM RIS end cap.
- Using the standard TM method of installing the RIS is not practical - rails wobble too much. What I did was loosen the triangle-sight and lengthened the front outer barrel section. I then fitted the RIS rails and pushed the tri-sight in position. If the RIS was still loose, I shortened the barrel. Then fitted the RIS again, and so forth.....
Once I got the tightest fit possible, I tightened the front outer barrel, fitted the RIS and finally, pushed the tri-sight in place. Not a bit of wobble of the RIS anymore. Oh yeah, if there are slight rail movements, just fatten the ears of the outer barrel and end cap - I used elec. tape.
- 2 ways to put a TM RIS on your ICS M4
1) w/ Marui barrel:
Pro - easiest, sturdy at the collar coz its metal
Cons - will still need to tighten nuts occasionally
2) w/ ICS barrel:
Pro - no barrel wasted, sturdy
Cons - need to replace ICS end cap (for hand guard) and collar ring, with Marui end cap (for RIS), and Marui collar ring
* I did this last night and the Marui RIS for an SR16 rails fits on the ICS M4, its just a bit loose so you will need to fine-tune the length of barrel and fatten the ears on the barrel so the rails will sit tight.
- Mosquito Molds M4a1 standard R.I.S. fits nice and snug with no modifications needed. Only thing I had to do was lengthen the barrel ONE full turn and the tighten it.

- The retractable stock version can hold a 9.6v 1700 mah in the fore grip.

Retractable Stock:
- Could not get the Marui ret. stock to fit on the ICS receiver, it seems a tight fit, so I did not pursue this. I was thinking of installing front SR rails and a crane style stock on the ICS M4. Also, the tube for the ICS ret. stock is much lighter than the Marui tube, presumably because it’s made of aluminum.
- I tried installing Marui retractable stock on the ICS M4 (w/ ret stock) and I found the Marui tube difficult to slide in. It would go in less than 1 inch then seemed to get stuck..
- According to the air smiths at Guns n Guys in Hong Kong, the Prime Crane Stock will fit and without replacing the stock stem. However, a hole needs to be drilled at the bottom of the stem closest to the body for the battery wiring.

Odds and Ends:
- The gearbox sound emanating from the ICS M4 when fired seems louder than on a Marui. I even compared it to a friend's Marui M4 fitted with similar specs. See Motor for fix…

Minor Fixes:
- On the lower gearbox, the prong holding the small spring for the electric contact switch, you can use a needle file to put a small canal, so the small spring will not detach easily.
- If your rear butt pipe droops down ward, you can place a small washer or better yet a lock washer, in front of the large slotted screw to straighten the butt.

taken from and
E Nomini Patri, E Fili, E Spiritu Sancti

My Old ASC Buy/Sell Rating
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Old July 5th, 2004, 00:19   #2
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Nice research man. Thanks for the link over. Much Appreciated!

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Old July 5th, 2004, 09:47   #3
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thanks for the summary ert. 21 pages is a lot to search through.
Props to you
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Old July 5th, 2004, 13:36   #4
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Old July 5th, 2004, 19:25   #5
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Heh, I just didn't want to have to sort through all that crap when these problems arise with my ICS (Hopefully they never do, but not everything is perfect)... So I figured I'd put it all down in one chunk for easy reference.

Oh, and I just added a few pertinent pictures...
E Nomini Patri, E Fili, E Spiritu Sancti

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Old July 5th, 2004, 21:21   #6
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great research Ert. I read something like 14 or something pages from the Flipino page. LOL
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Old July 5th, 2004, 21:53   #7
Join Date: Apr 2004
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The gearbox screw problem has been fixed with the ICS M4A1 version 2. All Canadian ICS M4A1s that are coming in are version 2, so don't worry about that one, very nice research Ert.
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Old July 5th, 2004, 23:32   #8
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Yowzah, I did not realize that the ICS motor pinion was so crappy
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Old July 5th, 2004, 23:48   #9
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Keep in mind that these issues were raised by the Filipino players. They have very different FPS rules there and they tend to upgrade the crap out of their guns and ride em hard. (Try PDI 210's and 12V batteries...)

I'm going to do only a few upgrades to my gun (spring, bushings, motor, and inner barrel...) so I don't anticipate the amount of problems they had and not to the extent that they experienced.
E Nomini Patri, E Fili, E Spiritu Sancti

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Old July 6th, 2004, 07:11   #10
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Worth Archiving for sure!

"Solving an imaginary world's contrived and over dramatic problems... 6 millimeters at a time."
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Old July 6th, 2004, 16:57   #11
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Thanks for taking the time. But I wonder if most of this information is from the version 1. Im sure most of these problems will be fixed in the version 2. I mean the mechbox screws were to short. How do you miss that one :roll: Almost seems like they didnt care. If most of this information was based on the version 1. Then it wouldnt matter much to us because all the ones in Canada are V.2. Do you know which version they are talking about?
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Old July 6th, 2004, 19:56   #12
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I assume they were referring to the Version 1's. They seemed to have their guns before they were available in Canada (at least to my knowlege). So yes, since we have version 2's, these problems *should* be addressed already, but you never know...

Also, some stuff will be the common to both versions. For example the motor will probably not change from the first version, and the options for mounting an RIS system on it won;t change... stuff like that. The general information about what works and what doesn't work with the gearbox in regards to aftermarket upgrades is also still relevant probably.
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Old July 7th, 2004, 04:00   #13
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Thanks again. Im really looking forward to getting mine. Should have it in my hands by the end of the week. Awwww Yaaaa :grin: Cant wait :xmas:
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Old July 23rd, 2004, 02:28   #14
Join Date: Jul 2003
As a note to anyone who is interested in the compatibility of the STAR mags, I used a few this past weekend with absolutely no problems, but there was a user who claimed that they only fed one bb from each mag into his gun, so it's still kinda up in the air until more people try em out.
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Old July 24th, 2004, 19:29   #15
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Here are some pics of my M4. Took it apart and took some pics.

Pictures Here
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