SSS.6.80 - Liberty Precision Machine Anthem-K and the Savage Model 10 PC .308 (Free Version)
/Liberty Precision Machine Anthem-K on a Savage Model 10 .308 with 20-in Barrel
The Anthem-K 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, including 300 Remington Ultra Magnum. It has a 1.74-inch diameter and is 5.22 inches long. The total length with the included direct thread adapter is 5.69 inches. The user may choose to use third-party adapters compatible with the 1.375”-24tpi system. The silencer is tubeless and all welded components are 17-4 stainless steel. The Anthem series of silencers have a removeable center aperture section for future distal orifice changes. The Anthem-K uses the serial-ID ring on the rear portion of the silencer, under license. The silencer weighs 12.3 ounces, and the included direct thread mount weighs 1.6 ounces, for a total system weight of 13.9 ounces, as tested. The Anthem-K can be obtained from Liberty Precision Machine.
PEW Science is an independent private testing laboratory and also the world’s only publicly funded 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 data production for this Sound Signature Review was funded in part by PEW Science Project PEW-LPM-027-001-22. Therefore, data pertaining to the Anthem-K in this Sound Signature Review is published with the express written permission of Liberty Precision Machine, LLC.
This review contains single-test results using the Anthem-K with the direct thread mount on the Savage Model 10 Precision Carbine rifle, chambered in .308WIN with a 20-inch barrel. Federal XM80 149gr ammunition was used in the tests. Test results are also available for the midsize version of this silencer, the Anthem-S, in Sound Signature Review 6.79.
- Section 6.80.1 contains the Anthem-K test results and analysis.
- Section 6.80.2 contains back pressure and Suppression Rating comparisons with selected .30 rifle silencers possessing a PEW Science Back Pressure Metric, Ω [Pa-1] in Omega Zone 5 and above. An updated Ω metric chart for the full suite of publicly evaluated .30 rifle silencers is also provided in this section. Further information about the Ω metric and Omega Zones can be obtained in PEW Science Research Supplement 6.40 (Public Article).
- Section 6.80.4 contains the review summary and PEW Science opinions.
Summary: When paired with the Savage M10 20” .308 and fired with Federal XM80, the Liberty Precision Machine Anthem-K, mounted with direct thread, achieved a Suppression Rating™ of 35.3 in PEW Science testing. As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.
Test data for the midsize version of this silencer, the Liberty Precision Machine Anthem-S, can be found in Sound Signature Review 6.79.
Relative Suppression Rating Performance is Summarized in SSS.7 - PEW Science Rankings
6.80.1 Liberty Precision Machine Anthem-K Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Anthem-K 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 PEW Science testing, research, and development with a membership, here. State-of-the-art firearm sound signature testing and research conducted by PEW Science is supported by readers like you.
Table 1. Liberty Precision Machine Anthem-K Sound Metric Summary
6.80.1.1 SOUND SIGNATURES AT THE MUZZLE
Real sound pressure histories 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 2.0 millisecond long portion of the first round sound pressure signature of the Anthem-K as measured 1.0 m left of the muzzle. There are four significant waveform features labeled:
The end cap exit event results in an initial overpressure peak magnitude of 141.2 dB.
Early jetting occurs, reaching an amplitude of 148.7 dB.
The second major jet reaches a peak amplitude of 152.1 dB, which is also the peak FRP.
Latent jetting occurs with an amplitude of 144.3 dB.
This is a somewhat typical sequence observed when firing supersonic .308WIN ammunition from a bolt-action rifle with an attached silencer that exhibits relatively low flow restriction (back pressure). Internal silencer design can significantly influence the measured timing and pressure amplitudes. Preliminary back pressure comparisons are shown in Section 6.80.3 of this review, with the PEW Science Back Pressure Metric, Ω [Pa-1].
Fig 1. Liberty Precision Machine Anthem-K First Round Bolt Action Rifle Muzzle Sound Pressure Signature
The waveform shown in Figure 1 possesses early time characteristics very similar to the FRP signature of silencers exhibiting flow restriction (back pressure) in PEW Science Omega Zones 4 and 5, such as the Rugged Razor762 (Review 6.16), the Rugged Radiant (Review 6.12), the Energetic Armament VOX S (Review 6.3), and the short configuration of the Silencer Central Banish 30 (Review 6.74) . As highlighted in previous PEW Science publications, some rifle silencers from Q, such as the Q Trash Panda (Review 6.4), exist in Zone 4 and possesses similar features of early time gas jetting. Like the Q Thunder Chicken (Review 6.20), the bullet exit event of the Trash Panda possesses an atypical gas jet coupling, characteristic of the bore and baffle design in Q rifle silencers.
The Liberty Precision Machine Anthem-K is the compact version of the Anthem-S tested in Sound Signature Review 6.79. The Anthem-K possesses a similar internal design, and exhibits a higher flow rate (lower back pressure) than the Anthem-S, resulting in a louder sound signature. The Anthem-K is 1.25 inches shorter than the Anthem-S, and 2 ounces lighter. There are some key design features in the Anthem-S that are not present in the Anthem-K.
Although not as quiet as the Anthem-S, the Liberty Precision Machine Anthem-K exhibits relatively balanced sound suppression performance for its size and flow rate:
For example, the Anthem-K has a muzzle Suppression Rating on par with that of the Dead Air Sandman-S (Review 6.11) on this platform, and eclipses its performance at the shooter’s ear, while being over an inch shorter and 7.8 ounces lighter.
Also notable is the comparison of the Anthem-K with the Rugged Radiant (Review 6.12); the Anthem-K is over 1.8 inches shorter than the Radiant and while it doesn’t quite match its muzzle (bystander) Suppression Rating, it eclipses its Suppression Rating at the shooter’s ear on this platform, with a similar flow rate.
An extremely interesting comparison is the Anthem-K with Energetic Armament VOX S (Review 6.3). The two silencers are relatively close in size, weight, and flow rate, but the Anthem-K achieves a Suppression Rating that is higher to both the shooter and to bystanders. The internal geometry and gas dynamics of the Anthem-K are significantly more advanced than that of the VOX S.
As mentioned previously in the PEW Science review of the Anthem-S, the Liberty Precision Machine Anthem technology represents a significant advancement in supersonic rifle suppression performance. However, unlike the Anthem-S, the Anthem-K does have some peers in the space that achieve higher performance by several metrics on this platform, such as the CGS Hyperion K (Review 6.28); a silencer that is lighter and quieter, with a higher flow rate. Like the CGS rifle silencers, the Liberty Precision Machine Anthem series represents next-generation supersonic rifle suppression optimization.
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 relative consistency of the internal silencer combustion and end cap exit event between all 5 shots during the test. These waveform feature consistencies in both gross amplitude and wave shape, from shot to shot, are discernable as a result of the high sample rate and raw, unfiltered data stream from PEW-SOFT. 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 in Figure 2a is 0.48 milliseconds (480 microseconds) and the total timescale in Figure 2b is only 0.13 milliseconds (130 microseconds). PEW-SOFT provides a sampling point every microsecond and the individual data points are shown in Figure 2b to illustrate this.
Fig 2a. Liberty Precision Machine Anthem-K Bolt Action Rifle Muzzle Sound Pressure Early-Time Peaks
Fig 2b. Liberty Precision Machine Anthem-K Bolt Action Rifle Muzzle Sound Pressure Shot 1 Peak
The primary sound signature pressure histories for all 5 shots with the Anthem-K are shown in Figure 3a. The sound signatures of Shot 1 and Shot 2 are shown in Figure 3b, in early time. 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 and Shot 3.
Fig 3a. Liberty Precision Machine Anthem-K Bolt Action Rifle Muzzle Sound Pressure Signature
Fig 3b. Liberty Precision Machine Anthem-K Bolt Action Rifle Muzzle Sound Pressure Signature, Short Time Window
Figure 4a. Liberty Precision Machine Anthem-K Bolt Action Rifle Muzzle Sound Impulse Signature
Figure 4b. Liberty Precision Machine Anthem-K Bolt Action Rifle Muzzle Sound Impulse Signature, Short Time Window
The Anthem-K exhibits FRP measured at the muzzle that is more severe to bystanders, relative to other shots, than the mid-size Anthem-S, in accordance with PEW Science inner ear modeling. The FRP is highlighted in both the pressure regime (Figure 3) and impulse regime (Figure 4). PEW Science postulates that one of the primary reasons for the more severe FRP with the Anthem-K is the more prolonged positive phase during early jetting (initiating at a time of approximately 30.2 ms in Figure 3b).
PEW Science Research Note 1: For a compact 30 caliber rifle silencer, the Anthem-K has consistent gas flow with relatively high sound suppression for the size and flow rate. The detrimental long duration early positive phase event during FRP notwithstanding, the silencer achieves performance that is now demonstratively not possible with older, more primitive truncated or curved cone mill-cut baffle technology in a similar size envelope (i.e. the aforementioned Dead Air Sandman-S and Rugged Radiant technologies). This, again, represents a shifting in supersonic rifle suppression to a new generation of performance.
PEW Science Research Note 2: The performance of the Anthem-K is unable to reach that of the CGS Hyperion K on this platform. This is important to note, as the Anthem-S was able to eclipse the performance of the CGS Helios QD (Review 6.13). Though similar, there are significant differences between the Helios QD and Hyperion K, in gas dynamics. The early-time gas expansion of the Anthem-S and Helios QD are similar. In the shorter design envelope, the Hyperion K mimics the early-time gas expansion behavior of the full size Hyperion; a technology that significantly increases early time flow rate, and in conjunction with its continuous outer annulus, the Hyperion K makes more efficient use of the silencer length than the Anthem-K. This performance differential, between four silencers from two manufacturers, highlights just a few of the nuanced performance factors of the next generation of supersonic rifle silencers.
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.
PEW Science has made a concerted effort to characterize the FRP phenomenon with true physiological human inner-ear response analyses. Additional PEW Science Member Research Supplements containing this information are released periodically.
6.80.2 Relative Suppression Rating and Back Pressure Comparisons (.30 Rifle Silencers)
The Anthem-K suppressor is intended to offer relatively balanced sound signature suppression and flow rate, in a compact size. PEW Science has developed an empirical relation to quantify the back pressure (flow restriction) of silencers. Figure 7 and Figure 8 show supersonic suppression and back pressure comparisons between selected 7.62mm (30 caliber) rifle silencers shown in public PEW Science Sound Signature Reviews, as of the date of this review publication. The results shown in Figure 7 and Figure 8 are calculated from real test data acquired with PEW-SOFT. Please note the following:
- The PEW Science Back Pressure Metric, Ω [Pa-1], may be generated for any silencer and suppressed weapon system using any suitable raw external overpressure signature data acquired 1.0 m left of the silencer end cap. PEW Science highly recommends data acquisition in accordance with The Silencer Sound Standard.
- Omega Zones are presented in Table 3, below, which are intended to provide guidance to weapons developers, silencer designers, and end-users, with regard to flow restriction characteristics of different silencer designs. It is very important to note that silencers possessing a relatively high Ω can still provide functional use on weapon systems. Some weapon systems are more sensitive to Ω than others.
- It is important to note that a silencer’s Omega Zone can shift when using a mounting scheme that differs from that used in the testing referenced in the published PEW Science Sound Signature Reviews. This phenomenon occurs due to some silencer mounting schemes significantly influencing flow restriction with some silencer designs.
- The theoretical lower limit of flow restriction, or so-called "zero back pressure" would be represented by the unsupressed state, Ω = 0 [Pa-1].
- PEW Science acknowledges that other dynamic events occur within a suppressed weapon system that can also influence weapon function. Therefore, PEW Science acknowledges that Ω is not the sole parameter one must consider for total supppressed weapon system operation. However, PEW Science postulates that the Ω metric influence can be significant.
- The Back Pressure Metric relations are most easily viewed on a logarithmic scale (See Figure 8).
Figure 7. Omega Back Pressure Metric And Suppression Rating Comparisons Of .308 Rifle Silencers Using PEW-SOFT Data and Analysis
As stated above, the PEW Science Back Pressure Metric is most easily viewed on a logarithmic scale. The metric is nonlinear; the shape of the trend in the data presented in Figure 8, below, illustrates the potential thresholds of extreme flow rate (approaching the unsuppressed state) and extreme flow restriction (approaching the trapping of the maximum amount of combustion byproducts in a system).
Figure 8. Omega Back Pressure Metric Comparisons Of .308 Rifle Silencers Using PEW-SOFT Data and Analysis
Omega characterizes silencer back pressure. It is important to note that back pressure is not blow back. The back pressure of a silencer is the flow restriction it introduces in a suppressed weapon system. The blow back phenomenon that can occur during the use of a suppressed weapon system is caused by the reciprocating system actuating too early relative to overpressure decay within the weapon system, resulting in exposure of excessive internal system overpressure to atmosphere. Some weapons may be tuned to function well with silencers in a high Omega Zone. Some weapons may require low-Omega silencers due to constraints in their operating system(s). Omega metric technical details can be found in PEW Science Public Research Supplement 6.40.
Table 2. PEW Science Back Pressure Metric Omega Zones And Suppressed Weapon System Functional Descriptions
The Anthem-K possesses gross characteristics and sound suppression performance, on average, that can best be described as a cross between a Rugged Radiant (Review 6.12) and short configuration of a Rugged Surge (Review 6.22); it’s lighter, shorter, and quieter than the short Surge, and similar in weight and flow rate to the Radiant. Users should note that the flow rate difference between the short Rugged Surge and Rugged Radiant, as reported in Figure 8, has been shown during internal PEW Science testing to influence semiautomatic 7.62x51mm NATO weapon system operation.
PEW Science Research Note 3: Like the Anthem-S, the performance of the Anthem-K on this platform represents that of systems created in the so-called post-PEW Science era in which the Silencer Sound Standard was published prior to the initiation of the entire product development cycle. PEW Science postulates that the combination of features, technology, and performance of silencers like the Anthem-K and Anthem-S may be considered next-generation in the current market.
It is extremely important to note that peak sound pressure [dB], peak sound impulse [dB-ms], and Omega (Ω) [Pa-1], alone, do not determine the sound supression performance of a silencer. It is the combination of these and other waveform parameters that form the total sound signature and the influence on human inner ear response. The Suppression Rating computation considers all of these factors.
6.80.3 Review Summary: Liberty Precision Machine Anthem-K on a Savage Model 10 .308 with 20-in Barrel
When paired with the Savage M10 20” .308 and fired with Federal XM80, the Liberty Precision Machine Anthem-K, mounted with direct thread, achieved a Suppression Rating™ of 35.3 in PEW Science testing.
PEW Science Subjective Opinion:
The Liberty Precision Machine Anthem-K is a compact and lightweight 30 caliber rifle silencer that exhibits advanced sound signature reduction and flow rate for its design envelope. The Anthem-K is constructed of 17-4 stainless steel and has a user-adaptable mounting system. The characteristics of the Anthem series, in totality, are advanced.
Like the Anthem-S, the Anthem-K possesses a highly efficient coaxial baffle assembly with optimized expansion volumes, though the volumes differ in the two silencers. Regardless, the gross technology characteristics enable the Anthem-K to continuously redirect high pressure gasses for efficient stagnation relief during the long durations characteristic of 7.62x51mm NATO combustion. It is important to note that the Liberty Precision Machine Anthem series does this without immediate venting from the proximal expansion (blast) chamber; a trait that separates it from the CGS Hyperion K. The Anthem-K does not possess a continuous outer annulus; in fact, the Anthem-K technology shares some similarities with that of the Dead Air Nomad baffle technology. However, the Anthem-K possesses key features that are more advanced than present in the Nomad, including a steeper baffle angle, differing expansion volumes and transitions, and advanced distal geometry. The performance of the Anthem-K, on this platform, for its size, reflects this technology advancement.
Notably, the Anthem-K has a muzzle Suppression Rating on par with that of the Dead Air Sandman-S on this platform, and eclipses its performance at the shooter’s ear, while being over an inch shorter and 7.8 ounces lighter. Also notable is the comparison of the Anthem-K with the Rugged Radiant; the Anthem-K is over 1.8 inches shorter than the Radiant and while it doesn’t quiet match its muzzle (bystander) Suppression Rating, it eclipses its Suppression Rating at the shooter’s ear on this platform, with a similar flow rate. An extremely interesting comparison is the Anthem-K with Energetic Armament VOX S. The two silencers are relatively close in size, weight, and flow rate, but the Anthem-K achieves a Suppression Rating that is higher to both the shooter and to bystanders. The internal geometry and gas dynamics of the Anthem-K are significantly more advanced than that of the VOX S.
The rear mount threading of the Anthem series is 1.375”-24tpi; relatively common in many modern rifle silencers. As a result of this common modular interface, a plethora of mounting systems may be used. The performance of the Anthem-S may be influenced by mounting system choice. The user’s choice of mount may balance system weight, length, durability, utility, and even back pressure of the silencer. The data presented by PEW Science in this Sound Signature Review was measured with the direct thread mount. Note that the center portion of the Anthem series endcap may be removed. This should be currently be considered a capability for future utilization by users.
Also notable is the licensed “Serial ID Ring” on the proximal end of the silencer. The Anthem series may be completely replaced by Liberty Precision Machine, at their discretion, should the silencer become damaged, while maintaining the same serial number. This is facilitated by the swaged fixity of the ring to the silencer body. The ring serves as the primary serialized part.
In this review, the Anthem-K 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.
