SSS.6.171 - Liberty Precision Machine Anthem-S2 QD and the Q mini FIX 300 BLK Subsonic (Free Version)
/Liberty Precision Machine Anthem-S2 QD on a Q mini FIX 300 BLK with 8-in Barrel
The Anthem-S2 QD is designed and manufactured by Liberty Precision Machine. It is a 30 caliber centerfire rifle silencer, intended to suppress most cartridges with projectiles appropriately sized to travel through the bore. It has a 1.74-inch diameter and is 7.5 inches long with the included ATLAS mount coupler and muzzle brake mount installed. The user may choose to remove the ATLAS coupler and use other third-party adapters compatible with the 1.375”-24tpi system. The silencer is tubeless and all welded components are stainless steel. The end cap of the Anthem-S2 QD has a center section removeable aperture for future distal orifice changes. The silencer also uses a serial-ID ring on the rear portion of the silencer, under license. The silencer, mount coupler, and muzzle brake weigh a total of 18.1 ounces, as tested. The Anthem-S2 QD can be obtained from Liberty Precision Machine Dealers.
PEW Science is an independent private testing laboratory and also hosts the world’s only independent public suppressed small arms research cooperative. Testing, data analysis, and reporting is generated with funding provided by PEW Science members. Any test data that is generated with any portion of private funding contains this disclosure. The testing and analysis production for this Sound Signature Review was funded in part by PEW Science Project PEW-LPM-087-001-24. Therefore, data pertaining to the Anthem-S2 QD in this Sound Signature Review is published with the express written permission of Liberty Precision Machine, LLC.
This Sound Signature Review contains single-test results using the Anthem-S2 QD with its direct thread mount on the Q mini FIX bolt action pistol, chambered in 300 BLK with an 8-inch barrel. Discreet Ballistics 190gr ammunition was used in the test.
Section 6.171.1 contains the Anthem-S2 QD test results and analysis.
Section 6.171.2 contains Suppression Rating comparisons with selected .30 rifle silencers in the subsonic flow regime.
Section 6.171.3 contains the review summary and PEW Science laboratory staff technical opinions.
Summary: When paired with the Q mini FIX 8” 300 BLK and fired with Discreet Ballistics 190gr Subsonic Target ammunition, the Liberty Precision Machine Anthem-S2 QD with the ATLAS coupler and brake mount achieved a composite Suppression Rating™ of 68.4 in PEW Science testing.
The supersonic .308 performance of the Liberty Precision Machine Anthem-S2 QD with the same mount system is detailed in Sound Signature Review 6.170, in which it achieved a composite Suppression Rating of 46.9.
As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.
Relative Suppression Rating Performance is Summarized in SSS.7 - PEW Science Rankings
6.171.1 Liberty Precision Machine Anthem-S2 QD Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Anthem-S2 QD is shown in Table 1. The data acquired 1.0 m (39.4 in) left of the muzzle is available for viewing to all. The data acquired 0.15 m (6 in) right of the shooter’s ear is only available to membership supporters of PEW Science and the Silencer Sound Standard. You can support public PEW Science testing, research, and development with a membership, here. State-of-the-art public firearm sound signature testing and research conducted by PEW Science is supported by readers like you.
Table 1. Liberty Precision Machine Anthem-S2 QD Sound Metric Summary
6.171.1.1 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 laboratory sound signature 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 laboratory testing; the recognized 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 are shown in Figure 1a. A zoomed-in timescale displays the region of peak sound pressure in Figure 1b, for the first three shots. The real sound impulse (momentum transfer potential) histories from the same 5-shot test are shown in Figure 2a. In Figure 2b, a shorter timescale is shown comparing the impulse of Shot 1 to that of Shot 3 and Shot 5.
Fig 1a. Liberty Precision Machine Anthem-S2 QD Bolt Action 300 BLK Muzzle Sound Pressure Signature
Fig 1b. Liberty Precision Machine Anthem-S2 QD Bolt Action 300 BLK Muzzle Sound Pressure Signature, Short Time Window
Figure 2a. Liberty Precision Machine Anthem-S2 QD Bolt Action 300 BLK Muzzle Sound Impulse Signature
Figure 2b. Liberty Precision Machine Anthem-S2 QD Bolt Action 300 BLK Muzzle Sound Impulse Signature
The Liberty Precision Machine Anthem-S2 QD has also been evaluated in the 7.62x51mm supersonic ammunition combustion regime (6.170). Some of the same design attributes enabling high performance with high pressure long duration combustion also pay dividends with lower pressure, shorter duration combustion. The subsonic 300 BLK performance of the Anthem-S2 QD is significantly high, particularly for the weapon operator on this host weapon.
The Liberty Precision Machine Anthem 2 series contains silencers that use an updated version of the technology implemented in the Anthem series, previously characterized in the test report of the Liberty Precision Machine Anthem-S (6.79). The Anthem-S2 QD examined in this test report is the mid-size iteration of the updated series, sharing design attributes with the Mach S. For all intents and purposes, the Anthem 2 series silencers are Mach series silencers manufactured from stainless steel instead of titanium. Therefore, performance of the Mach S is postulated to be similar to that of the Anthem-S2 QD in this report. However, there is a significant performance factor observed during testing and subsequently examined during analysis that indicates Anthem-S2 QD may provide somewhat lower operator hazard than the Mach-L on this weapon system. The phenomena responsible for this risk differential was discussed in report 6.170 and is repeated below.
Anthem 2 and Mach Series Research Note: A distinct difference between the Mach-L and Anthem-S2 QD noted above may be the mount, depending on user implementation. In this test program, the Anthem-S2 QD was tested with the included ATLAS HUB-compatible threaded coupler and Liberty Precision Machine Liberty Bell muzzle brake. This is the factory configuration of the silencer. As its sister silencer, the titanium Mach S, includes a direct-thread adapter like the larger titanium Mach L, care must be taken when extrapolating test results and analysis from a silencer in the Anthem 2 series to the Mach series, and vice versa. PEW Science laboratory testing and analysis indicates that there are two primary performance differences between the two mounting choices:
The direct-thread mount decreases the distance between the muzzle orifice and the first reflector (blast baffle) of the silencer. This dimension controls initial wave expansion and likely influences suppression performance by changing the proportion of annular utilization and primary bore propagation in early time.
The Anthem 2 and Mach series are constructed of stainless steel and titanium, respectively. The ATLAS and brake combination included with the Anthem-S2 QD are stainless steel. There also exist titanium versions of the ATLAS coupler. The threaded connections and material densities, in combination with dimensional changes in (1), may result in impedance mismatches that change internal combustion signature propagation to the free field in early time. These structural resonance-driven phenomena have a measurable influence on signatures propagating to the operator’s head.
Use of thread couplers like the ATLAS and associated mounts may induce damping effects, which may reduce resonance in some systems, depending upon silencer construction and materials. At signature severities characterized by high(er) Suppression Ratings (e.g. 60-zone and above), these measurable signature differences contribute to severity differentials that are somewhat above nominal and are audible to many users. The primary presentation of undamped resonance phenomena may be subjectively interpreted by the operator as a "metallic pinging," a short duration "ping” or "ring,” or other "metallic sounding” event. These are high-frequency effects and are discernible to the shooter when comparing the Mach-L to the Anthem-S2 QD with subsonic 300 BLK (reports 6.164 and this report). The shooter’s ear Suppression Rating differential between those reports reflects this. Although the Mach-L has a less severe free field signature in totality, the operator is in very close proximity to the blast chamber when fielding this weapon system, and therefore directly subjected to the aforementioned phenomena in early time. Late time phenomena dictate that most operators will still interpret the Mach-L to “sound quieter” with subsonic 300 BLK on this host weapon, despite its slightly lower shooter’s ear Suppression Rating when compared to the Anthem-S2 QD evaluated in this report. Although the more severe 7.62 NATO platform likely masks this type of resonance differential to the operator, it is also measurable in the combustion regime examined in report 6.170. The reader may examine the early time combustion signature in Figure 1b of report 6.163 (the direct-thread mounted Mach-L with .308) and compare it to Figure 1b in 6.170. Additionally, to isolate only material change as a variable, the reader may examine the same in Figure 3b of report 6.79 (the direct-thread mounted previous generation steel Anthem-S with .308) and compare it with 6.163.
The member version of this report presents Figure 3 and 4 in Section 6.171.1.2 with associated commentary.
In summary, mount type, geometry, material configurations, and other differences that may be considered trivial by some users in a suppressed small arm weapon system, can influence measured signatures, and therefore operator and bystander risk metrics, in unintended ways. PEW Science encourages thoughtful consideration if extrapolating testing and analysis results to use cases that differ from the explicitly noted test conditions and parameters.
At the weapon muzzle, and to bystanders in the free field, the Anthem-S2 QD presents a more severe signature than does the larger Mach-L. The signature differences noted in the above measured test data include:
Relatively higher amplitude overpressure signature with shorter duration blowdown (Fig. 1a).
Immediate first-round-pop (FRP) divergence with early onset in both pressure space and impulse space (Fig. 2b), without significant initial FRP rarefaction.
Absence of latent shot impulse increase (Fig. 2b), similar to the consistency measured in 7.62 NATO testing (ref. 6.170, Fig. 2b).
Significant gas throttle after lower frequency internal combustion (Fig. 1b).
The performance factors described in (1) and (2) underscore the primary mechanisms of more severe gross signature severity from the Anthem-S2 QD when compared to the larger Mach-L. However, the performance factors described in (3) and (4) highlight factors that result in a slightly higher shooter’s ear Suppression Rating (slightly higher degree of operator risk reduction in the free field) with the Anthem-S2 QD than the Mach-L in this tested configuration. This may be counterintuitive to the reader; the shooter’s ear signature analysis in the full member version of this report provides further context.
PEW Science Research Note 1: It is fortuitous that the staged design of the Anthem-S2 QD, previously highlighted in its 7.62 NATO testing, behaves as a “gas trap,“ though to less of degree than its larger sister silencers, the Mach-L and Anthem-L2. This type of behavior, when moving from supersonic high pressure ammunition suppression, often translates well to subsonic low pressure ammunition suppression. When transitioning from the later to the former, less robust performance observations often occur. For example, the Q Full Nelson (6.99) demonstrates significantly high subsonic suppression performance. However, its Cherry Bomb-mounted sister silencer, the Q Thunder Chicken (6.20), demonstrates less than optimal supersonic suppression performance. A similar analog may be examined when comparing the Q Half Nelson (6.29) with subsonic 300 BLK and the Q Trash Panda (6.4). This is due to the distinct lack of pressure stagnation relief in the subsonic-centric Q rifle silencer designs. Typically, high performance supersonic silencers also perform well with subsonic ammunition. A notable exception is Flow-Through designs from HUXWRX (OSS). The high degree of subsonic performance loss in those systems is highlighted in the evaluation of the HX-QD 762 (6.45). Combustion regime pressure and duration-dependent performance transitions between Q rifle silencers and HUXWRX rifle silencers are diametrically opposed.
PEW Science Research Note 2: As a consequence of its shorter length, the Liberty Precision Machine Anthem-S2 QD does not approach the holistic performance of the larger Liberty Precision Machine Mach-L. One of the biggest performance differences between the two silencers on this platform, besides their gross muzzle (bystander) suppression capabilities, is their FRP control. As also observed in the 7.62 NATO testing of the Anthem-S2 QD, the bystander FRP performance of the silencer in the subsonic 300 BLK ammunition combustion regime is also lacking. On average, the relative bystander signature severity with the Anthem-S2 QD on this platform, during the first shot, is almost 2.5 times as great as subsequent shots. This severity differential is due to not only amplitude, but rise time and other signature parameters. However, for the weapon operator, this severity differential is mostly inconsequential in the free field. This is due to pressure field shape and early-time factors in close proximity to the operator, discussed in Section 6.171.1.2 and previously discussed in Section 6.164.1.2 of the Member Version of the Mach-L subsonic 300 BLK test report. Operators will still be subjected to late-time signature components that cause them to interpret the Mach-L as “quieter” in totality. However, the acute risk to the operator is slightly lower with the ATLAS and brake-mounted steel Anthem S2 QD. When moving to the upper performance echelons of subsonic 300 BLK bolt-action suppression, early time combustion propagation behavior more significantly contributes to the pressure field. It is not the bystander that is subjected to this adverse performance differential; it is the operator.
PEW Science Research Note 3: The holistic performance of the Liberty Precision Machine Anthem-S2 QD with subsonic 300 BLK is relatively close to that of both the legacy Sig SRD762Ti-QD (6.39) and Resilient Suppressors Jolene (6.138). However, there are distinct performance differences between the three silencers; namely, FRP control. Of the three, the Sig silencer possesses superior FRP masking capability in this combustion regime.
In pure muzzle suppression performance, the Anthem-S2 QD performs similarly to the Silencer Central Banish 30 Gold (6.70), Surefire SOCOM300-SPS (6.57), Diligent Defense Enticer L (6.88), and CAT ODB (6.122). Of those silencers, the CAT ODB provides the most advanced FRP control, with the highest gross flow rate. It is somewhat of an outlier in the Standard research pedigree. The Enticer L and Banish 30 Gold have severe FRP, with the FRP from the SOCOM300-SPS being moderate on this host weapon.
In level of protection to the operator, in the free field, the Anthem-S2 QD provides unusually high average performance. This is reflected in its shooter’s ear Suppression Rating of 67.3. This is on-par with the CAT ODB and nominally higher than that of the Mach-L. The aforementioned frequency-driven phenomena responsible for this performance differential are further discussed in the full Member Version of this article.
Comparisons with other silencers in the subsonic 300 BLK combustion regime are shown below.
6.171.2 Suppression Rating Comparison - Subsonic 300 BLK
The Liberty Precision Machine Anthem-S2 QD was developed with a focus on high pressure sound signature reduction (PEW Science Suppression Rating), without regard to gross flow rate. As previously discussed, its subsonic sound signature suppression performance is very high. Figure 6 shows a performance comparison of many 30 caliber rifle silencer configurations tested with the subsonic 300 BLK cartridge shown in public PEW Science testing, to date. Unsuppressed and suppressed Suppression Ratings are shown for both the shooter and bystanders. The silencers in the figure are shown in no particular order.
Figure 6. Suppression Rating Comparisons Of .30 Rifle Silencers Using PEW-SOFT 300 BLK Subsonic Test Data
The holistic performance of the Liberty Precision Machine Anthem-S2 QD with subsonic 300 BLK is relatively close to that of both the legacy Sig SRD762Ti-QD (6.39) and Resilient Suppressors Jolene (6.138). However, there are distinct performance differences between the three silencers; namely, FRP control. Of the three, the Sig silencer possesses superior FRP masking capability in this combustion regime.
In pure muzzle suppression performance, the Anthem-S2 QD performs similarly to the Banish 30 Gold (6.70), Surefire SOCOM300-SPS (6.57), Diligent Defense Enticer L (6.88), and CAT ODB (6.122). Of those silencers, the CAT ODB provides the most advanced FRP control, with the highest gross flow rate. It is somewhat of an outlier in the Standard research pedigree. The Enticer L and Banish 30 Gold have severe FRP, with the FRP from the SOCOM300-SPS being moderate on this host weapon.
It is interesting to note that the shooter’s ear Suppression Ratings of both the Anthem-S2 QD and the Mach-L are very close to that of the Combat Application Technologies CAT/ODB/A1/718 (6.122). The size envelopes, flow rates, technologies, and suppression methodologies from the LPM and CAT silencers are radically different. A much more restrictive silencer, the Mach-L produces a much less severe pressure field adjacent to the muzzle. But, to the operator in the free field, risk is comparable. The Anthem-S2 QD is less restrictive, but remedies some high frequency signature components in the direct-thread Mach-L system that present as audible on this host at these high levels of performance. Environment, signature features, and host, all significantly influence gross severity of a suppressed small arm weapon system.
PEW Science Research Note 6: As discussed in the 7.62 NATO evaluation of the larger Mach-L silencer, the upper echelons of 30 caliber suppression performance continue to be stretched (ref. Research Note 3, 6.163). It is again postulated that hybrid designs, staged designs, and other technological advancements will continue to emerge and define the state-of-the-art. High pressure stagnation relief, repeated axially through long(er) centerfire rifle silencers, is no longer sufficient to push the performance envelope in the supersonic ammunition combustion regime, but continues to demonstrate high performance with shorter duration lower pressure systems (subsonic 300 BLK). This is demonstrated by the Full Nelson, Hydrogen-L, Jolene, and others. Primitive and small silencers like the Energetic Armament VOX-S (6.25) will continue to be eclipsed in performance, in this combustion regime. For compact designs to excel in performance with subsonic 300BLK, they must employ much more advanced technology.
The difference in sound signature suppression performance from silencers in the subsonic 300 BLK suppression regime can be extremely significant. The user is encouraged to be mindful of the degree to which sound signature suppression, and resulting personnel hazards, can vary across designs. Small arm weapon system suppression performance is a spectrum. The PEW Science Suppression Rating and the Silencer Sound Standard help quantify this spectrum for end users and industry, objectively.
6.171.3 Review Summary: Liberty Precision Machine Anthem-S2 QD on a Q mini FIX 300 BLK with 8-in Barrel
When paired with the Q mini FIX 8” 300 BLK and fired with Discreet Ballistics 190gr Subsonic Target ammunition, the Liberty Precision Machine Anthem-S2 QD with the ATLAS coupler and brake mount achieved a composite Suppression Rating™ of 68.4 in PEW Science testing.
The supersonic .308 performance of the Liberty Precision Machine Anthem-S2 QD with the same mount system is detailed in Sound Signature Review 6.170, in which it achieved a composite Suppression Rating of 46.9.
As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.
PEW Science Laboratory Staff Opinion:
The Liberty Precision Machine Anthem-S2 QD is a mid-size 30 caliber rifle silencer that demonstrates extremely high suppression performance for its length. For a traditionally-manufactured system, the performance of the Anthem-S2 QD is an example of the upper echelon of staged design efficiency and consistency. The technology in the steel Anthem-S2 QD is also implemented in the titanium Mach series; the Anthem 2 series may be considered identical to the Mach series, other than construction material and included mount(s). Both Anthem 2 and Mach series silencers possesses user-adaptable mounting systems.
Significant and efficient pressure stagnation relief with accompanying downstream restriction is the primary combination of gross performance attributes in the Anthem 2 and Mach series that produce the noted efficiency in the measured pressure field with 7.62 NATO cartridges. Some of the same design attributes enabling high performance with high pressure long duration combustion also pay dividends with lower pressure, shorter duration combustion. The subsonic 300 BLK performance of the Anthem-S2 QD is strong, but FRP control is somewhat lacking. However, due to some material and mount factors, its free field operator risk reduction on this platform is on-par with that of the larger Mach-L; this is a notable feat.
The holistic performance of the Liberty Precision Machine Anthem-S2 QD with subsonic 300 BLK is relatively close to that of both the legacy Sig SRD762Ti-QD and Resilient Suppressors Jolene. However, there are distinct performance differences between the three silencers; namely, FRP control. Of the three, the Sig silencer possesses superior FRP masking capability in this combustion regime.
In pure muzzle suppression performance, the Anthem-S2 QD performs similarly to the Banish 30 Gold, Surefire SOCOM300-SPS, Diligent Defense Enticer L, and CAT ODB. Of those silencers, the CAT ODB provides the most advanced FRP control, with the highest gross flow rate. It is somewhat of an outlier in the Standard research pedigree. The Enticer L and Banish 30 Gold have severe FRP, with the FRP from the SOCOM300-SPS being moderate on this host weapon.
It is interesting to note that the shooter’s ear Suppression Ratings of both the Anthem-S2 QD and the Mach-L are very close to that of the Combat Application Technologies CAT/ODB/A1/718. The size envelopes, flow rates, technologies, and suppression methodologies from the LPM and CAT silencers are radically different. A much more restrictive silencer, the Mach-L produces a much less severe pressure field adjacent to the muzzle. But, to the operator in the free field, risk is comparable. The Anthem-S2 QD is less restrictive, but remedies some high frequency signature components in the direct-thread Mach-L system that present as audible on this host at these high levels of performance. Environment, signature features, and host, all significantly influence gross severity of a suppressed small arm weapon system.
The included brake mount is easy to install in the ATLAS coupler included with the Anthem-S2 QD, and possesses hex-wrench features on the exterior. The ATLAS coupler may be removed and other mounts compatible with the so-called HUB threading system may be installed. This feature allows the Anthem-S2 QD to be used with a variety of weapon systems.
In this review, the Anthem-S2 QD performance metrics depend upon suppressing a subsonic intermediate rifle cartridge. While the sound signature of such cartridges can be suppressed to levels that may result in the desire of the shooter and bystanders to not wear hearing protection, PEW Science encourages the reader to remain vigilant with regard to all subsonic rifle cartridge suppression claims. The gas volume and combustion products created by firing a subsonic intermediate rifle cartridge such as 300 BLK are still significant; the measured pressure and impulse magnitudes, and their durations, illustrate this fact.
The hearing damage potential of subsonic rifle use is not insignificant. PEW Science encourages the reader to consider the Suppression Rating when deciding on an appropriate silencer and host weapon combination for their desired use.
