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General Information

ICS has really outdone themselves on this gun.
First Impressions:
After opening a plain cardboard shipping box, and tearing out all of the packing paper, revealed a very flashy box that is typical of ICS. The box featured both the SIG 551 and 552 on the cover with a Swiss Arms Trademark Sticker with some other Cyber Gun logos. Upon opening the box I was greeted with a very impressive spread. The 551, two hi-cap mags, a manual, cleaning/unjamming rod, a DVD, and a bottle of about 1000 ICS brand .20g BB's. Go ahead and use them. ICS makes a decent BB.
The DVD showcases ICS's line of AEG's and the IGLM. Plus, it has many useful assembly and disassembly guides, although it does not have the assembly or disassembly guide for the SIG. The included manual does a very good job of explaining how to disassemble and reassemble your SIG, up until dis-assembling the gearbox and the such. The magazines feature a ready mag system that allows the user to clip magazines together, thus saving time reloading. The handguards feature three rails to mount lasers, bipods, forward grips, and possibly an underbarrel grenade launcher.


The SIG itself has a stamped steel upper and lower receiver, metal trigger, metal sights, metal swinging trigger guard that allows for ease of use with gloves, metal ambidextrous selector switch, metal handguard rails. The bolt handle is made of a metal piece with the actual handle molded of polymer around it. The rest of the body is made of a nylon reinforced polymer that is extremely strong. The Swiss Arms Trademarks are absolutely wonderful, as they make the receivers really stand out. Unfortunately, mine wore off after about a month, and I was forced to paint them over to prevent the receiver from rusting out in the areas exposed to the elements.


The SIG features a G3 type hopup unit. The inner barrel is made of brass, but is a step up from your usual stock barrel. This once seems to be in the range of 6.06-6.04mm in diameter, and is crowned expertly. The inner barrel length is 370mm, slightly longer than an M-4. These factors give you outstanding accuracy, which you will read about later. Oddly enough, the gun has a longer inner barrel, but is shorter than an M-4 by about 1.5-2 inches.


ICS's SIG utilizes a very solid Version 3 Gearbox. Inside you will find a very nice set of ICS gears that are shimmed very well, 7mm solid steel bushings, an M120 non-pitched spring that delivers around 360-370 fps, a polycarbonate piston and silent piston head with o-ring. everything is greased with just the right amount lube, unlike some AEGs that are grease tubes themselves, or barren deserts.
However you will find some proprietary parts to the gun. First, it has a custom air nozzle and selector plate. It also has a mid-pin motor, which does not give the user as much upgradability as a short or long-pin motor. However, ICS has included in this version their famous Turbo 3000 and in their later series of SIG, will be their Infinite (Infinity) motor. It still does a wonderful job of cranking out the BB's and keeping everything running like clockwork.


After hearing the good, the bad and the ugly reviews about this gun, I decided to debunk some of the myths that surround the gun.

I first wanted to see just how large of a battery I could fit into the handguard. I was told that only a stick type battery would fit. I was actually able to fit a 9.6v 2000mah butterfly battery in the lower handguard. With a bit of convincing however, the battery fits snugly and works beautifully. With that in place, I began to put the SIG through it's testing.

I was also told that the SIG had average accuracy. Similar to that of an average M-4.
I tested out the SIG's accuracy with .20g BB.s. It chronoed at 358-367FPS, perfect for field games or maybe some CQB.
At 25 feet the SIG was nailing the target every time. I backed out to 50 feet with exactly the same results. Then at 75 feet, the same thing. I moved out to 100 feet. The SIG hit the target with astonishing accuracy. It still hit the target every time. I backed out to 125feet. Then the SIG's accuracy seemed to diminish a bit, only hitting the target 9/10 times. Still though, being able to hit a man-sized target at that distance with a stock gun is pretty impressive. I moved out to 150 feet. Then I noticed that the SIG was having a harder time hitting my the target. It scored 7/10 shots. I moved out to 175 feet. Still the SIG managed to hit the target only 4/10 shots though.
The rate of fire on the SIG is impressive too. Shooting 17-19 rps (1020-1140 rpm) on a 9.6v battery.

The other myth is that the gun uses a custom gearbox.
WRONG. The SIG uses any old Version 3 gearbox, as stated above.

Overall, the ICS SIG 551 is one heck of an AEG. It's amazing accuracy combined with a high rof makes a very lethal weapon on the field. And those attributes also make it a very versatile weapon. It could used a short DMR due to it's accuracy and fps, or it can be used a room sweeper due to it's high rof and folding stock. It will surely turn heads and attract attention on the field because it is not something that is seen everyday or is commonplace like how some AEGs are.

Superb build quality
Rate of fire
Magazine capacity (470 rounds)
Swinging trigger guard-ease of use with gloves
Different sighting apertures. 4 in back, 2 in front
Ease of disassembly and reassembly
Functional bolt and bolt release

Bolt can be brittle and break with excessive use
Large plastic orange flash hider (best left on for Law-Enforcement)
Stiff selector switch (will break-in after use)
Swinging trigger guard- can get in the way
No top RIS/RAS rail
Polymer handguards
Polymer Rails (can be replaced with metal ones)



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