CGS SCI-Six Suppressor - Dedicated 5.56 NATO Silencer

MSRP: $1,129.00
(You save $79.00 )
when available, ships from our shop in 1 to 3 weeks; ATF approval required
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CGS SCI-Six Suppressor

Designed for optimal performance by operators for operators.

The question always comes up when looking at suppressors: "Why this can?" More and more suppressor manufacturers are coming to market with more and more choices. Choices are good, but maybe 20 years ago, it was easier to buy a suppressor: fewer choices, large manufacturers, lots of marketing. Innovation and testing and the science of sound and back pressure and the advance of rapid prototyping has brought the consumer more choices, and quite frankly, better cans.

Back to the SCI-Six. This suppressor was literally designed for operators. Designed for the shooter whose life depends upon his tools. In a unique collaboration between the design team at CGS, a former Navy SEAL at Irregular Defense, and based upon feedback from true operators in the field, the SCI-Six was born, with the sole goal of making a combat 5.56 NATO rifle run at its best. 

So, the answer to why this can: You only want this can, if you want the best performing can for a semi-auto or fully automatic 5.56mm rifle that can knock doors down, shoot at night, be thrown into the back of a vehicle or into the mud, and picked back up and works every time.  The SCI-SIX is a total collaboration with CGS and Irregular Defense.  This is a machine gun rated rifle suppressor made of Inconel 718, but with DMLS 3-D "printing" technology.  SCI-SIX is designed to optimize performance with the 5.56mm NATO cartridge, while drastically reducing audible and visual signature.

In the SCI-Six, CGS has focused on:

  • The lowest sound profile
  • Reduced flash signature
  • Low gas blow-back
  • Repeatable POI
  • Minimal size and weight
  • Durability to drop in the desert or hit equipment in a vehicle or helicopter

Irregular Defense is working on the best battle gun in 5.56 NATO, and the suppressor collaboration with CGS Group, has produced the SCI-Six. To know Bobby and Slade is to know these guys respond to the heroes who need the best. Using top of the line design work at CGS, and the iterative nature of additive manufacturing to test and learn and revise and rework, and use testing and scientific instruments to measure sound and pressures; CGS can accomplish in days what would take other manufacturers weeks or longer. CGS is not interested in spending money on advertising or marketing. They live to make a difference for operators. And, when something good comes out of their design and rapid manufacturing methodology, we might get a peak and get to use it.

The advanced gas flow dynamics of the SCI-SIX also allows for higher operator safety with greater amounts of the gas exiting the fore end of the suppressor, rather than being redirected back to the shooter.

At Charlie's, we seek out the innovators, and the guys who make products that are fantastic. We see the work that CGS does for people and organizations that should not be mentioned in print, and ask, "How can we get this for our commercial customers?" It is a unique experience to see great products and only wish we could have them on our Website. Then comes SCI-Six.

One can think of the SCI-Six as the evolution of the Helios, and in many ways it is. But, unlike the Helios, the SCI-Six is a single rifle caliber suppressor. The Helios is more adaptable and using titanium also accepts a number of calibers, while the SCI-Six is mission specific to the M4 style rifle and is constructed of Inconel. In many ways, if the SCI-Six were available 20 years ago, one can imagine it being what the Knights NT4 or the Surefire 556 RC2 became: combat suppressors dedicated to the Mk18 and M4A1 carbine. If the soldiers, Marines, and sailors of 2003 only had what is available now in 2023, CGS would be a household name, for sure.

In the design of the SCI-Six, the objectives of sound suppression, flash signature reduction and durability are balanced with less gas in the shooter's face, size and weight, and ultimately the ability of the suppressor to finish the mission without failure. In using advanced additive manufacturing, there are no welds to fail. There are no geometries that are limited by mills and lathes. The advanced geometries of the baffle area provide the means to get to low back pressures, decibel reduction and extreme durability, and no doubts as to concentricity. The geometries also lead to gas and heat dissipation that could not be achieved through traditional tooling operations.

SCI-SIX operates with an advanced venting design. It possesses ancillary venting that occurs early in the geometry directly in the blast chamber. This allows the SCI-SIX to exhibit a higher flow rate in early time than typical for its bore. The venting directs to a portion of the annulus (under the “skin” of the suppressor), separate from the main chamber and bore; and continues to the front of the suppressor. This is a patented and exclusive technology that CGS GROUP has common to all of their center fire rifle cans. The SCI-SIX has a threaded end, so you have options to change the venting and flow rate with different end caps.

Let's face it, the world of 3D printing is new, and using heated metal particles to create suppressors is very new. CGS has been at the forefront of additive manufacturing and has learned a lot. The Hyperion suppressor is, to-date, the landmark of 3D printed suppressors. In making the SCI-Six, CGS Group utilized the Hyperion variable core diameter (VCD) design to make the SCI-Six stronger and better in its class, and can better control heat and pressures to avoid hot spots forming. The first baffle chamber, for example, is vented to allow for the forward flow of gasses outward and around the core, flowing to lower pressure areas inside the can. The flow moving forward is vented around the core and then reintroduced into the core, while the exterior gases flowing around the core have an alternate path through an array of vents in the cap, thus reducing the heat signature at night.

The SCI-Six is attached to a proprietary muzzle device with reverse threading and a taper to naturally fit the interior contours of the SCI-Six suppressor. The taper-mount provides for a solid seal and a solid lock, so the suppressor is not moving while shooting. The tapered surface allows for larger contact area that is not dependent upon a barrel maker to have a perfect 90 degree fit at the end of the threads, thus creating a stronger and more secure connection between the rifle and the suppressor.

Pew Science has tested the SCI-Six, and when looking at the performance both at the shooter's ear and the muzzle, it is one of the better performing 5.56mm suppressors tested. It is similar in sound reduction to the Surefire RC2 and the HUXWRX OSS suppressors, and it outperforms the Knights NT4, the Razor 556, Turbo T2, Polonium, and Saker 556. Note: This is only sound reduction, and not other factors that make the SCI-Six what it is, but the comparisons are important.


  • Weight: 17 oz
  • Material: Inconel 718
  • Length: 6.5"
  • Diameter: 1.68"
  • Finish: Ionbonded DLC black
  • Pew Science rating of 34.7 and 149.7 db (shooters ear with 10.3" Mk18 rifle)
  • Muzzle Device Included: short 1/2X28 barrel threads; reverse threading into suppressor; tapered fit



For a review, see the Pew Science sound review of the CGS SCI-Six

Photos courtesy of CGS Group, SC-Irregulars, @10firty6preciosn (on Instagram) and Carin West

Buying and shipping through Charlie’s is easy, but there is some information you need to know. This item must ship to FFL holder. No civilian exceptions.

 1) Check your state laws to make sure the federally regulated item you want to purchase is legal in your state.

 2) Find your FFL… Have your dealer send us a copy of their FFL and SOT to Charlie’s (Make them earn their fee!). Not every FFL is a SOT or Class 2 / Class 3 dealer.

3) Be patient! You should hear from our compliance department within 3-4 business days. If not, feel free to reach out for a status update.

That’s it! We try to make this process as simple as possible for our customers. Please click the “Buying a Firearm” tab at the top of this page for more information.


THIS IS A SERIALIZED ITEM.  It must ship to a Federal Firearms License holder.  No civilian exceptions.

Buying and shipping through Charlie’s is easy, but there is some information you need to know. Only a federally licensed firearms dealer may receive a firearm or federally regulated serialized item (like a receiver or suppressor). We cannot ship these items directly to you. Please follow these steps to process your transaction:

1)     Check your state laws to make sure the federally regulated item you want to purchase is legal in your state. Your FFL dealer should be able to give you all of the necessary information regarding your state specific laws. But, if we ship to your FFL, and there is a legal issue, we cannot accept a return. So please make sure that you know and follow your local and state laws.


2)     A quick google search will show you what Federal Firearms Licensed (FFL) dealers are in your area. When you are ready to purchase, contact the FFL dealer you would like to use and get their shipping address. During the check-out, put YOUR address in the “billing” section and the FFL DEALER’S address in the “shipping” section. If you don’t know your FFLs address, that’s okay. You can send the information later.


3)     After check out, make sure to contact your FFL dealer to ensure they will receive your shipment for you (most do this for a small fee, but you should always double check).


4)     Have your dealer send us a copy of their FFL to Charlie’s does not reach to your FFL (MAKE THEM EARN THEIR FEE!!!)


5)     Be patient! In order to ensure we remain compliant with all federal laws, our compliance department is kept separate from our sales and operations team. Please allow a few days for our compliance officer to verify all of your dealer’s documents and ensure all federal laws are being observed. You should hear from our compliance department within 3-4 business days. If not, feel free to reach out for a status update.


That’s it! We try to make this process as simple as possible for our customers, but if you are unfamiliar the process or have any other questions, please visit our How to Buy a Suppressor page for more details.