CGS SCI-Six Suppressor – FDE

The CGS Group SCI-Six in FDE Cerakote — a 3D-printed Inconel 718 5.56 NATO rifle suppressor co-designed with Irregular Defense and rated for machine-gun-pace fire.

• Collaboration with Irregular Defense: designed around feedback from end users running short-barrel 5.56 rifles
• DMLS additive-manufactured Inconel 718 — no welds to fail, geometries that cannot be cut on a mill or lathe
• FDE Cerakote finish over CGS’s Ion-bonded DLC baseline — a second cook in the Cerakote shop for clone-correct tan
• Proprietary taper-mount muzzle device included — reverse thread into the can, taper seal, no reliance on a perfect 90-degree shoulder
• Machine-gun rated for the 5.56 NATO cartridge

The SCI-Six is the product of a three-party collaboration: CGS Group’s suppressor design team, Irregular Defense (whose principals include former Naval Special Warfare operators), and the shooters testing hardware at the muzzle. The design brief was narrow — a 5.56 NATO can sized for a short-barrel carbine, low on first-round pop, low on gas blowback, durable enough to absorb drops in the desert or contact with vehicle and airframe hardware. Every geometry choice traces back to that brief.

Construction is Direct Metal Laser Sintering of Inconel 718 — the same high-nickel alloy used in turbine hot sections. DMLS builds the baffle stack as one continuous piece, removing the weld lines that are the usual failure mode on welded-baffle cans. More importantly, it lets CGS place venting and geometries that a milling or lathe operation cannot produce. The blast chamber on the SCI-Six vents early into an annular path under the outer skin, then forward and out the cap — a patented CGS Group flow path common across the company’s centerfire rifle line. The net effect is lower back pressure into the rifle and less gas pushed back at the shooter.

Mounting is via a proprietary reverse-thread muzzle device with a tapered seat. The taper lineage traces back to the Ops, Inc. over-the-barrel mount that is part of the Mk12 SPR’s signature footprint; Sig and Q have run taper-mount designs more recently. The taper-seat seals on cone contact rather than on a 90-degree shoulder, which means a barrel that is not perfectly faced at the threads still indexes and locks repeatably. Zero shift between sessions is what the design is chasing.

Third-party testing from Pew Science places the SCI-Six at a 34.7 suppression rating and 149.7 dB at the shooter’s ear on a 10.3″ Mk18 rifle, putting it in the same performance band as the Surefire RC2 and HUXWRX OSS cans, and ahead of the Knight’s Armament NT4, the SilencerCo Saker 556, and the Sig SRD 556. Sound reduction is one variable of many — back pressure, flash signature, weight, and durability all matter on a duty can — but the data is publicly available and worth reading.

The FDE finish is a commercial choice rather than a program spec. CGS delivers the Ion-bonded DLC suppressor, which goes back to the Cerakote shop for FDE; customers who want the baseline black Ion-bonded finish can order that variant instead.

Specifications

• Caliber: 5.56 NATO (machine-gun rated)
• Weight: 17 oz
• Length: 6.5″
• Diameter: 1.68″
• Material: Inconel 718, DMLS additive-manufactured
• Finish: Ion-bonded DLC with FDE Cerakote overcoat
• Mount: Proprietary taper-seat reverse-thread muzzle device (1/2×28), included
• Pew Science rating: 34.7 / 149.7 dB at shooter’s ear on 10.3″ Mk18

NFA item: this suppressor must ship to an FFL/SOT dealer — no civilian exceptions. Verify your state allows the transfer before ordering. Have your dealer email a copy of their FFL and SOT to Charlie’s; expect to hear from our compliance team within 3–4 business days. See the Pew Science sound review of the CGS SCI-Six for the full test data.

We keep these in stock when we can. Reach out if the color or mount config needs tweaking — we will square you away.