SSS.6.13 - CGS Helios QD and the Savage M10 PC .308
/CGS Helios QD on the Savage Model 10 .308 with 20-in Barrel
The Helios QD is designed by CGS Suppressors. It is a centerfire rifle silencer intended for use on semiautomatic and automatic 5.56 mm host weapons, but possesses a 30 caliber bore and can suppress many cartridges, up to and including .300 Remington Ultra Magnum, with no barrel length restrictions. It has a 1.75-inch diameter and is 7.2 inches long. The silencer mounts to the host firearm with several available mounting schemes, including direct-thread. An adapter ring is included to convert the rear female thread to use third-party adapters compatible with the 1.375”-24tpi system. Additionally, the user may choose from two end-caps; a solid and vented version. The main silencer body is constructed from 718 Inconel using additive manufacturing (DMLS 3D printing); the internal baffle geometry is fully integrated with the silencer body and the silencer possesses linked coaxial internal flow path geometry that is utilized differently based upon end-cap selection. The end-caps and mounts are constructed from heat treated 17-4 stainless steel. The silencer weighs 20.7 ounces with the 5/8”-24tpi direct-thread adapter installed. The Helios QD can be obtained from Silencer Shop.
This review contains test results using the Helios QD with both the solid and vented end-caps on the Savage Model 10 Precision Carbine rifle, chambered in .308WIN with an 20-inch barrel. Federal XM80C 149gr ammunition was used in the test.
Summary: When paired with the Savage M10 20” .308 and fired with Federal XM80C, the CGS Helios QD with the solid end-cap in the direct-thread configuration achieved a Suppression Rating™ of 44.5 in PEW Science testing. With the vented end-cap in the same direct-thread configuration with the same host weapon and the same ammunition, the Helios QD achieved a Suppression Rating of 23.2.
6.13.1 Helios QD Sound Signature Test Results (Solid End-Cap)
A summary of the principal Silencer Sound Standard performance metrics of the Helios QD with its solid end-cap is shown in Table 1. The data acquired 1.0 m (39.4 in) left of the muzzle is available for viewing to all. This is a members-only review and includes pressure and impulse waveforms measured at the shooter’s ear. PEW Science thanks you for your support; further testing, research, and development of PEW-SOFT and the Silencer Sound Standard is made possible by members like you!
Table 1. CGS Helios QD (Solid End-Cap) Sound Metric Summary
6.13.1.1 SOUND SIGNATURES AT THE MUZZLE
Real sound pressure histories from a 5-shot test acquired with PEW-SOFT™ are shown below. The waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science testing is 1.0 MS/s (1 MHz). The peaks, shape, and time phasing (when the peaks occur in relation to absolute time and to each other) of these raw waveforms are the most accurate of any firearm silencer testing publicly available. PEW-SOFT data is acquired by PEW Science independent testing; the industry leader in silencer sound research. For more information, please consult the Silencer Sound Standard.
Figure 1 shows a 1.1 millisecond long portion of the first round sound pressure signature of the CGS Helios QD as measured 1.0 m left of the muzzle. There are four significant waveform features labeled:
An initial pressure pulse out of the silencer, after the bullet exits the end-cap, causes a 141.5 dB peak
As gas exits the silencer from the primary combustion event, the measured sound pressure caused by gas jetting increases to 147.0 dB.
The gas continues to vent to atmosphere with increasing pressure magnitude, reaching another major peak of 146.5 dB.
Latent gas exiting the silencer causes the highest peak sound pressure of 149.1 dB.
This long-duration gas venting phenomenon observed when firing supersonic .308WIN ammunition from a bolt-action rifle with an attached silencer indicates high flow restriction (back pressure); however, internal silencer design can significantly influence the measured timing and pressure amplitudes.
Fig 1. Helios QD (Solid End-Cap) First Round .308 Bolt Action Rifle Muzzle Sound Pressure Signature, 09-MAY-2020
Closer views of the first peak of all shots (Fig 2a) and highest peak of the first shot (Fig 2b) are shown below. Figure 2a illustrates the consistency of the bullet end-cap exit event between all 5 shots during the test, prior to the influences of internal silencer gas environment. This event is plainly visible and decoupled from the majority of the primary combustion event due to the high gas flow restriction exhibited by the CGS Helios QD Suppressor. Figure 2b shows points later in time during Shot 1 as the maximum sound pressure occurs from the primary combustion event. Note that the total timescale displayed in Figure 2a is 0.28 milliseconds (280 microseconds) and the total timescale in Figure 2b is only 0.10 milliseconds (100 microseconds). PEW-SOFT provides a sampling point every microsecond and the individual data points are shown in Figure 2b to illustrate this.
Fig 2a. CGS Helios QD (Solid End-Cap) First Round .308 Bolt Action Rifle Muzzle Sound Pressure First Peaks 1, 09-MAY-2020
Fig 2b. CGS Helios QD (Solid End-Cap) First Round .308 Bolt Action Rifle Muzzle Sound Pressure FRP Peak, 09-MAY-2020
The primary sound signature pressure histories for all 5 shots with the Helios QD suppressor are shown in Figure 3a. The sound signatures of Shot 1 and Shot 2 are shown in Figure 3b, in the regions of peak sound pressure. Note the same peak events are labeled for Shot 1 that were previously labeled in Figure 1. The real sound impulse (momentum transfer potential) histories from the same 5-shot test are shown in Figure 4a. In Figure 4b, a shorter timescale is shown comparing the impulse of Shot 1 to that of Shot 2.
Fig 3a. CGS Helios QD (Solid End-Cap) .308 Bolt Action Rifle Muzzle Sound Pressure Signature, 09-MAY-2020
Fig 3b. CGS Helios QD (Solid End-Cap) Peak View of Muzzle Sound Pressure Signature, 09-MAY-2020
Figure 4a. CGS Helios QD (Solid End-Cap) .308 Bolt Action Rifle Muzzle Sound Impulse Signature, 09-MAY-2020
Figure 4b. CGS Helios QD (Solid End-Cap) .308 Bolt Action Rifle Muzzle Sound Impulse Signature, 09-MAY-2020
The measured first-round-pop (FRP) is significant and is evident in the pressure regime during the initial gas jetting phase and the latent phase. Note that after the initial impulse step peak occurs at approximately 30 ms, the impulse of Shot 1 continues to increase, whereas the impulses of the subsequent shots experience an initial flat slope followed by a more gradual slope (Fig. 4b). The fastest rise-time to peak impulse occurs in Shot 1, as expected.
The shape, timing, and magnitudes of the early-time pressure pulses and overall shape of the impulse waveforms measured at the muzzle, from shot-to-shot, are relatively consistent. Note that the long duration gas venting phase occurs in all shots and the overall positive phase impulse plateau is relatively pronounced (Figure 4); this is similar to the behavior observed in the SilencerCo Omega 300 test documented in review 6.10. In that respect, the high back pressure behaviors of the Omega 300 and Helios QD are similar. What is not similar, however, is the impulse step-peak occurring in the Helios QD test at approximately 30.5 ms during Shot 1 and approximately 0.25 ms later in subsequent shots. This behavior is similar to that observed in the Rugged Radiant test documented in review 6.12. But, unlike the Radiant, the secondary impulse plateau of the Helios QD is of significant duration.
PEW Science note: Another notable observation from the measured data is the relatively long rise-time to peak impulse exhibited by the Helios QD in this test, when compared to that of the SilencerCo Omega 300. The rise-time to peak impulse (peak momentum transfer potential) measured 1.0 meter left of the muzzle, of the Helios QD with its solid end-cap, after the first shot when firing supersonic .308WIN ammunition, is measured to be slower than any centerfire rifle silencer shown in the the Sound Signature Reviews, at the time of this review publication. This is one objective measurement that indicates the Helios QD with the solid end-cap exhibits relatively slow gas flow rate and therefore significant back pressure characteristics. More detailed and direct comparisons are provided in Section 6.13.3 of this review.
As typically indicated, first-round sound signatures always differ from subsequent shots, as the atmosphere within the silencer changes. The FRP phenomenon cannot always be shown by viewing only the peak sound pressure. This is one of the reasons why The Silencer Sound Standard requires examining multiple sound signature metrics. Ammunition consistency can play a role in the determination of FRP, however, the close examination of measured pressure and impulse waveforms typically excludes ammunition from the possible factors influencing true FRP, due to the relative consistency of most high quality factory ammunition.
As shown above, FRP significantly influences rise time to peak impulse. Therefore, FRP waveforms must be excluded from the data set when formulating flow rate (back pressure) calculations that utilize the waveform data from subsequent shots.
6.13.1.2 SOUND SIGNATURES AT SHOOTER’S EAR
Real sound pressure histories from the same 5-shot test acquired with PEW-SOFT at the shooter’s ear are shown below. Again, the waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science testing is 1.0 MS/s (1 MHz).
The primary sound signature pressure histories at the ear for all 5 shots are shown in Figure 5. The primary sound signature history is shown on the left. A zoomed-in timescale is displayed on the right, in the region of peak sound pressure for Shot 1 and Shot 2. The real sound impulse (momentum transfer potential) histories at the ear from the same 5-shot test are shown in Figure 6. Again, full and short timescales are shown.
Figure 5a. CGS Helios QD (Solid End-Cap) .308 Bolt Action Rifle Ear Sound Pressure Signature, 09-MAY-2020
Figure 5b. CGS Helios QD (Solid End-Cap) .308 Bolt Action Ear Sound Pressure Signature, Short Time Window, 09-MAY-2020
Figure 6a. CGS Helios QD (Solid End-Cap) .308 Bolt Action Rifle Ear Sound Impulse Signature, 09-MAY-2020
Figure 6b. CGS Helios QD (Solid End-Cap) .308 Bolt Action Rifle Ear Sound Impulse Signature Peaks, 09-MAY-2020
Similar to the measurements at the muzzle, there is significant FRP evident when examining the waveforms measured at the shooter’s ear in early time (Figure 5b). Note that, again, the fast rise-time to peak impulse is evident in Shot 1 (Figure 6). Also note the very similar pressure and impulse magnitudes prior to the gas completely exiting the weapon system (between 27 and 30 ms). The supersonic .308WIN platform creates significant sound signature even before the gas completely exits the weapon system, as was shown in the measured muzzle sound pressure and impulse signatures in the previous section.
As typical, the overall sound signature measured at the shooter’s ear possesses significantly less amplitude in both the pressure and impulse regimes than the signature measured at the muzzle (refer to Table 1). Furthermore, the application of both pressure and impulse at the shooter’s ear is delayed when compared to the pressure and impulse at the weapon muzzle. The combination of varying amplitude and rise time to peak amplitude influences the response of the human ear.
The long duration gas venting from the Helios QD with its solid end-cap is plainly visible in the impulse measurements at the shooter’s ear, and the peak impulse magnitudes in Shot 2 through Shot 5 are significantly lower than typically seen for this type of weapon system (Figure 6).
6.13.2 Helios QD Sound Signature Test Results (Vented End-Cap)
A summary of the principal Silencer Sound Standard performance metrics of the Helios QD with its vented end-cap is shown in Table 2. The data acquired 1.0 m (39.4 in) left of the muzzle is available for viewing to all. As stated in Section 6.13.1, this is a members-only review and includes pressure and impulse waveforms measured at the shooter’s ear. PEW Science thanks you for your support; further testing, research, and development of PEW-SOFT and the Silencer Sound Standard is made possible by members like you!
Table 2. CGS Helios QD (Vented End-Cap) Sound Metric Summary
6.13.2.1 SOUND SIGNATURES AT THE MUZZLE
Real sound pressure histories from a 5-shot test acquired with PEW-SOFT™ are shown below. The waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science testing is 1.0 MS/s (1 MHz). The peaks, shape, and time phasing (when the peaks occur in relation to absolute time and to each other) of these raw waveforms are the most accurate of any firearm silencer testing publicly available. PEW-SOFT data is acquired by PEW Science independent testing; the industry leader in silencer sound research. For more information, please consult the Silencer Sound Standard.
The primary sound signature pressure histories for all 5 shots with the Helios QD suppressor with its vented end-cap are shown in Figure 7a. The sound signatures of Shot 1 and Shot 2 are shown in a smaller time window in Figure 7b. The real sound impulse (momentum transfer potential) histories from the same 5-shot test are shown in Figure 8a. In Figure 8b, a shorter timescale is shown comparing the impulse of Shot 1 to that of Shot 2.
Fig 7a. CGS Helios QD (Vented End-Cap) .308 Bolt Action Rifle Muzzle Sound Pressure Signature, 09-MAY-2020
Fig 7b. CGS Helios QD (Vented End-Cap) .308 Bolt Action Rifle Muzzle Sound Impulse Signature, 09-MAY-2020
Figure 8a. CGS Helios QD (Vented End-Cap) .308 Bolt Action Rifle Muzzle Sound Impulse Signature, 09-MAY-2020
Figure 8b. CGS Helios QD (Vented End-Cap) Bolt Action Rifle Muzzle Sound Impulse Signature, 09-MAY-2020
As was shown in the test with the solid end-cap, the measured pressure regime first-round-pop (FRP) with the vented end-cap is evident when comparing Shot 1 to Shot 2 (Fig 7b). Figure 8b also shows FRP in the impulse regime. Note the FRP is not nearly as significant with the vented end-cap as it is with the solid end-cap.
Again, the overall shape of the impulse waveforms measured at the muzzle, from shot-to-shot, are extremely consistent, highlighting the silencer’s overall sound performance consistency at the muzzle after the FRP, as well as the relative consistency of the tested firearm configuration. Note that the time phasing of Shot 2 in Figure 7b and Figure 8b was shifted in time, globally, to illustrate key waveform features between the FRP event and the subsequent shot. As stated in the figure notes, gas jetting anomalies with the vented end-cap caused by significant early-time flow cause slight PEW-SOFT data acquisition triggering time differences from shot to shot. Note that the sound overpressure and impulse measured at the muzzle with the vented end-cap on the Helios QD are significantly higher than that with the solid end-cap configuration. The back pressure is also significantly lower; that data is presented in Section 6.13.3 of this review.
PEW Science note: First-round sound signatures always differ from subsequent shots, as the atmosphere within the silencer changes. The FRP phenomenon cannot always be shown by viewing only the peak sound pressure. This is one of the reasons why The Silencer Sound Standard requires examining multiple sound signature metrics. Ammunition consistency can play a role in the determination of FRP, however, the close examination of measured pressure and impulse waveforms typically excludes ammunition from the possible factors influencing true FRP, due to the relative consistency of most high quality factory ammunition.
6.13.2.2 SOUND SIGNATURES AT SHOOTER’S EAR
Real sound pressure histories from the same 5-shot test acquired with PEW-SOFT at the shooter’s ear are shown below. Again, the waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science testing is 1.0 MS/s (1 MHz).
The primary sound signature pressure histories at the ear for all 5 shots through the Helios QD suppressor with its vented end-cap are shown in Figure 9a. A zoomed-in timescale is displayed in Figure 9b, in the region of peak sound pressure for Shot 1 and Shot 2. The real sound impulse (momentum transfer potential) histories at the ear from the same 5-shot test are shown in Figure 10. Again, full and short timescales are shown.
Figure 9a. CGS Helios QD (Vented End-Cap) .308 Bolt Action Rifle Ear Sound Pressure Signature, 09-MAY-2020
Figure 9b. CGS Helios QD (Vented End-Cap) .308 Bolt Action Rifle Ear Sound Pressure Signature, Short Time Window, 09-MAY-2020
Figure 10a. CGS Helios QD (Vented End-Cap) .308 Bolt Action Rifle Ear Sound Impulse Signature, 09-MAY-2020
Figure 10b. CGS Helios QD (Vented End-Cap) .308 Bolt Action Rifle Ear Sound Impulse Signature Peaks, 09-MAY-2020
The previously observed FRP characteristics measured at the muzzle are again evident in the ear measurements in both the magnitude and durations of the overall pressure and impulse signatures shown in Figure 9b and once again in Figure 10a with the large impulse peak during Shot 1.
As typical, the overall sound signature measured at the shooter’s ear possesses significantly less amplitude in both the pressure and impulse regimes than the signature measured at the muzzle (refer to Table 2). Furthermore, the application of both pressure and impulse at the shooter’s ear is delayed when compared to the pressure and impulse at the weapon muzzle. The combination of varying amplitude and rise time to peak amplitude influences the response of the human ear.
Note the significantly higher average pressure and impulse measured at the weapon muzzle and at the shooter’s ear in this test of the vented end-cap when compared to that of the solid end-cap. This significantly more intense sound signature results in a significantly reduced Suppression Rating when using the Helios QD suppressor with the vented end-cap.
6.13.3 Relative Back Pressure and Suppression Rating Comparison (.30 Rifle Silencers)
PEW Science Research Note: As of February 2021, back pressure characterization has undergone refinement and Rev.2 of the Back Pressure Metric has been developed. Research is ongoing. Please see back pressure research updates starting with Sound Signature Review 6.36.
The Helios QD is intended to be user-configurable to adjust back pressure. PEW Science is currently conducting silencer back pressure research. Figure 11 shows preliminary relative back pressure comparisons between each of the 7.62mm (.30) rifle silencers shown in public PEW Science Sound Signature Reviews, as of the date of this review publication. The results shown in Figure 11 are calculated from real test data acquired with PEW-SOFT. Please note the following:
The time to reach peak gas momentum transfer potential, as measured 1.0 m left of the weapon muzzle, is the objective quantity used to generate the back pressure data summary.
The first shot from each test is omitted from the back pressure computations due to internal gas environment characteristics within the silencer (FRP) that influence peak impulse amplitude, wave-shape, and timing.
Data is normalized to the silencer with the highest back pressure and Suppression Rating shown, which is the Helios QD with the solid end-cap in this review.
Figure 11. Back Pressure and Suppression Rating Comparisons of .308 Rifle Silencers using PEW-SOFT Data
From the above data, it can be concluded that the CGS Helios QD suppressor is capable of significantly reduced back pressure when used with its vented end-cap. The use of the vented end-cap results in back pressure approximately 1 percent higher than that of the Rugged Radiant in its short configuration. This is noteworthy, as the Radiant only has two baffles in its short configuration, and the Helios QD with its vented end-cap achieves a 6% higher suppression rating. The use of the vented end-cap also allows the Helios QD to have 19% lower back pressure than the Dead Air Sandman-S, but with a 21% lower Suppression Rating.
With its solid end-cap, the CGS Helios QD suppressor achieves a higher suppression rating than any other silencer shown in Figure 11. It has a 14% higher Suppression Rating than the SilencerCo Omega 300. However, its back pressure with the solid end-cap is significant, and 19% higher than that of the Omega 300.
PEW Science note: The relative percentages described in this section are only valid when examining the data normalized to the solid end-cap configuration of the Helios QD in Figure 11. Ongoing PEW Science back pressure research is being conducted on unsuppressed weapon system scaling to enable gross weapon system comparisons. Membership contributions to PEW Science help fund such research.
When the CGS Helios QD suppressor is used with its vented end-cap, its back pressure potential is significantly lower, but it is significantly louder.
6.13.4 Review Summary: CGS Helios QD on the Savage Model 10 .308 with 20-in Barrel
When paired with the Savage M10 20” .308 and fired with Federal XM80C, the CGS Helios QD with the solid end-cap in the direct-thread configuration achieved a Suppression Rating™ of 44.5 in PEW Science testing. With the vented end-cap in the same direct-thread configuration with the same host weapon and the same ammunition, the Helios QD achieved a Suppression Rating of 23.2.
PEW Science Subjective Opinion:
The CGS Helios QD is a relatively compact 5.56mm machine gun silencer, but the bore tapers from 0.36-in to 0.375-in at the exit, allowing safe use with 30 caliber projectiles. Given its sound suppression performance demonstrated in PEW Science testing, this multi-use silencer may be extremely attractive to some users. The objectively high sound suppression performance of the Helios QD with its solid end-cap is significant. The weight of the silencer is also significant.
The silencer has changeable end-caps; the user can choose between high sound suppression with high back pressure (solid end-cap configuration) and low sound suppression with low back pressure (vented end-cap configuration). Tolerance stacking with variable end-caps is sometimes an issue with such silencer designs. However, as the Helios QD is 3D printed, it is possible that manufacturing tolerances of the “core” section may be controlled more easily than in traditional manufacturing; PEW Science does not anticipate any issues. The repeatability, concentricity, and general alignment of 3D printed designs and their interface with machined parts is a subject of continued research interest. As 3D-printed parts continue to be introduced into silencer component manufacturing, designs are expected to evolve.
The Helios QD possesses tapered interfaces at threaded connections to assist with alignment and fastening. This assists with retention of the end-caps and the mount interfaces. The ability to use a socket to tighten and loosen the end-caps is a welcome convenience. It is important to note that in addition to the two end-caps, the silencer includes two direct thread mounts and a QD adapter to interface with the 1.375”-24tpi mount system. Therefore, depending on the muzzle device length, the Helios QD may be used with various third-party mounting systems.
The internal baffle geometry of the Helios QD is patented and referred to as Hyperion Technology, present in all of their rifle silencers. The blast chamber immediately vents flow into two primary directions; a main axial flow path and a coaxial outer flow path. The utilization of the coaxial chamber is unique, in that main axial flow is introduced into existing coaxial flow approximately halfway forward of the blast baffle. In addition to this secondary flow introduction, the coaxial chamber may be vented to atmosphere at the forward section of the silencer by using the vented end-cap. The vented end-cap significantly changes the functionality of the silencer. It is important to note that the vented flow with the vented end-cap originates only from the coaxial chamber.
The Helios QD is extremely durable and has undergone a significant amount of automatic and semi-automatic sustained fire testing by CGS on 5.56mm barrels as short as 5 inches and on belt-fed weapons with no apparent damage. Interested parties are encouraged to contact CGS for more information on such third-party testing. The Helios QD has no barrel length restrictions or firing schedule restrictions.
PEW Science has not yet evaluated and characterized the sound signature of the Helios QD on semi-automatic or automatic 5.56mm weapon systems. Those evaluations are forthcoming.
In this review, the Helios QD performance metrics depend upon suppressing a supersonic centerfire rifle cartridge; no easy task. PEW Science encourages the reader to remain vigilant with regard to all supersonic centerfire rifle suppression claims. The gas volume and combustion products created by the firing of the supersonic .308WIN cartridge are significant; the measured pressure and impulse magnitudes, and their durations, illustrate this fact.
The hearing damage potential of supersonic centerfire rifle use is significant. PEW Science encourages the reader to consider the Suppression Rating when deciding on an appropriate silencer and host weapon combination for their desired use.
