Hello everyone and welcome back to TFB’s Silencer Saturday brought to you by Yankee Hill Machine, manufacturers of the YHM Turbo K rifle suppressor. Last week we shared some upcoming reviews and I thought we could kick the season off with a look at the CGS HELIOS QD – a suppressor marked as 5.56mm but is capable of handling almost any caliber you can throw at it. Full-auto rated and without any barrel restrictions, the CGS HELIOS is billed as the pinnacle of hard use silencers with features not found anywhere else. But how does the HELIOS sound? Let’s take a look.

Much thanks to Silencer Shop for letting me borrow the whole CGS lineup.

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We have talked extensively about gas blowback and its effects on certain firearm actions when running a suppressor. I’ll summarize: the more gas that is trapped by a silencer and stopped from exiting the muzzle, the greater the likelihood of having that gas redirected towards the shooter. This phenomenon is particularly prevalent in direct gas impingement firearms (AR-15s) and blowback firearms (many of the pistol caliber carbines in an AR platforms). Closed action guns like bolt action rifles don’t have to worry about blowback since the action is manually opened long after the gases are trapped in the silencer and exit the muzzle.

The CGS HELIOS is meant to be an end-of-the-world style suppressor that can withstand heavy punishment. Most silencers of this type are small diameter direct thread tubes devoid of threaded attachments that can be failure points. Instead the HELIOS comes as a kit for host weapon adaptability, allowing for gas flow out the front for semiautomatic rifles or extreme quiet for bolt action setups. The HELIOS QD kit also comes with two thread mount modules and an 1.375×24adapter for other manufacturer’s quick detach muzzle device systems.

All these features come with some added weight; if you want to withstand abuse and also have modularity, there will a price to pay. At nearly 20 ounces and somewhere around $1500, the CGS HELIOS is near the top of scale compared to some competitors. But if you need these features, there is no substitute and they aren’t cheap or easy to design and manufacture. Keep that in mind when you get feel the sticker shock effect.

Lets look at the details and specifications directly from CGS.

SILENCER SATURDAY #168: The CGS HELIOS QD Suppressor Kit

The CGS HELIOS QD is a short, quick attach rifle silencer designed specifically for 5.56mm rifles and carbines. The patented “Varying Core Diameter” technology unique to CGS Suppressors is unlik anything the firearms industry has ever seen before. This unique design allows for peak sound reduction for its size and elimination of the flash signature as well as consistent, minimal and repeatable point of impact shift.  By using a taper interface between the muzzle device and the signature suppressor, we ensure the muzzle device threads will not carbon lock.  The HELIOS QD utilizes a full DMLS 718 Inconel design for maximum strength and extreme durability.

The HELIOS QD system was designed to be extremely versatile.  The generous .36 bore significantly reduces back pressure and muzzle flash while also allowing the suppressor to be used with multiple calibers.  The HELIOS QD comes with a 1/2×28 threaded rear cap, a 5/8×24 threaded rear cap, and an adapter ring threaded in 1.375×24 to accept a plethora of industry QD mounting solutions.  The interchangeable rear caps are complimented with interchangeable front caps as well.  A sealed front cap is provided for the maximum sound reduction possible.  A ported front cap is included to ensure blowback mitigation for left hand shooters or for use with calibers or weapon systems that may be prone to over-gassing.

The HELIOS QD is full auto rated with no barrel length restriction and will handle up to and including 300 Norma Magnum.  The HELIOS QD has a lifetime warranty and due to the design of the suppressor the serial ring can be removed and welded to another core should the need ever arise.  We fully warranty the HELIOS QD on the MAXIM DEFENSE PDX and MDX line of firearms in any caliber, any barrel length, and in both semi and fully automatic firing modes.

The CGS Helios QD Kit Includes:

• CGS Helios QD
• 5/8 x 24 TPI Direct Thread Mount
• 1/2 x 28 TPI Direct Thread Mount
• Solid Low Profile Front Cap
• Vented Low Profile Front Cap
• QD Adapter Mount for 1.375 x 24 TPI amounts
• Hook Wrench for QD adapter

Friendly Reminder: Always read the freaking manual.

Which Helios End Cap Do I Use?

The CGS HELIOS comes with two end caps. The Solid Low Profile Front Cap acts like a traditional silencer. The Vented Low Profile Front Cap acts as a “flow bypass” type silencer. For bolt action rifles, use the solid front cap to maximize suppression. For semiautomatic rifles, especially those with short barrels, use the vented front cap to maximize at-the-ear suppression and reduce the blowback of gases and particulate matter.

Using The 1.375 x 24 QD Adapter

Over the past five years, the 1.375 x 24 thread pitch has become a near standard among manufacturers. The list of adapters and muzzle devices is that are compatible is long. This is the part in the conversation where we argue about tapers and their position in relation to the threads. Actually, it’s not – use whatever system you like and trust then move on with your life.

Shooting With The CGS Helios

Let’s start out by saying that the SIG Rattler is a difficult rifle to suppress. Although it’s an internet myth that this contract gun was never meant to be suppressed – simply not true. But with a 5.5” barrel even 300BLK is going to be dishing out some serious pressure, gas and unburned powder. The short stroke gas piston action does help, but with the wrong silencer, this PDW can be a bit loud and gassy (insert dad joke here).

But let’s talk about the Helios on a bolt action 300BLK first. With subsonic ammo, this can is scary quiet. No matter which end cap you use (I couldn’t tell the difference) the HELIOS is simply impressive. Supersonic rounds were no joke either, being somewhere just below unsuppressed .22LR noise levels. The HELIOS delivers a star performance on 300BLK bolt action rifle.

Back to the Rattler. With the vented front cap, the HELIOS handles the short barrel easily. The report has a unique, low thwap/woosh sound, presumably as the gasses push out of the front vented cap. Whether or not you’d consider the HELIOS on the SIG Rattler as “hearing safe” is up to you. It’s one of the quietest suppressors I’ve heard on the Rattler, but my rule of thumb is that all centerfire rifle rounds in semiautomatic hosts need additional hearing protection. Impressive suppression nonetheless.

When it comes to 300BLK, this is a top performing silencer. The HELIOS is built like a tank, has options for forward venting or traditional end caps and offers the ability to use other manufacturer’s mounts. The “penalties”, for lack of a better term, are its price and weight. At somewhere between $1400 and $1500, the HELIOS lingers in the top price bracket for its class. And approaching 20 ounces means that it lands slightly above other hard-use rifle suppressors. If those two factors don’t bother you, this is a fantastic silencer.

Next week we’ll conjure up a post sample machine gun to test the CGS HELIOS 5.56mm fully automatic fire rating. Have a great week and we’ll see you here next weekend for another Silencer Saturday.

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