SSS.6.132 - BOSS Silencers Chairman and the Savage Model 10 PC .308 (Free Version)
/BOSS Silencers Chairman on a Savage Model 10 .308 with 20-in Barrel
The Chairman is manufactured by Black Ops Suppression Systems (BOSS). It is a 30 caliber centerfire rifle silencer, intended to suppress many cartridges with projectiles appropriately sized to travel through the bore on barrel lengths 10.5-in and longer. The Chairman has a 1.5-inch diameter and is 8.1 inches long with no mount. The rear of the silencer is threaded with the so-called HUB 1.375”-24tpi threading, allowing the use of a variety of mounting solutions. With the included direct thread mount, the silencer’s length increases to 8.4 inches. The silencer is available in two versions; a stainless steel and titanium model. Both silencers possess a Grade 9 titanium tube. The stainless steel model has 17-4 heat treated stainless steel baffles, mount, and end cap, whereas the titanium model has Grade 5 titanium baffles, mount, and end cap, maintaining the heat treated stainless steel blast baffle. The steel model was tested and weighs 15.5 ounces, and the direct thread mount weighs 1.8 ounces, for a total system weight of 17.4 ounces. The Chairman can be obtained from BOSS Silencers.
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 data production for this Sound Signature Review was funded in part by PEW Science Project PEW-BOSS-067-001-23. Therefore, data pertaining to the Chairman in this Sound Signature Review is published with the express written permission of Black Ops Suppression Systems.
This review contains single test result using the Chairman 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.
- Section 6.132.1 contains the Chairman test results and analysis.
- Section 6.132.2 contains back pressure and Suppression Rating comparisons with selected .30 rifle silencers possessing a PEW Science Back Pressure Metric, Ω [Pa-1] in Omega Zones 6 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 6.132.3 contains the review summary and PEW Science opinions.
Summary: When paired with the Savage M10 20” .308 and fired with Federal XM80, the BOSS Chairman with the direct thread mount, achieved a Suppression Rating™ of 43.5 in PEW Science testing. 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
6.132.1 BOSS Silencers Chairman Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Chairman 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. BOSS Silencers Chairman Sound Metric Summary
6.132.1.1 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.
The primary sound signature pressure histories for all 5 shots with the Chairman are shown in Figure 1a. The sound signatures of Shot 1 and Shot 2 are shown in Figure 1b, in early time. 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 2 and Shot 3.
Fig 1a. BOSS Silencers Chairman Bolt Action Rifle Muzzle Sound Pressure Signature
Fig 1b. BOSS Silencers Chairman Bolt Action Rifle Muzzle Sound Pressure Signature, Short Time Window
Figure 2a. BOSS Silencers Chairman Bolt Action Rifle Muzzle Sound Impulse Signature
Figure 2b. BOSS Silencers Chairman Bolt Action Rifle Muzzle Sound Impulse Signature, Short Time Window
Figure 1b shows a 2.4 millisecond long portion of the sound pressure signatures of the first two rounds fired from the BOSS Silencers Chairman, as measured 1.0 m left of the muzzle. There are several significant waveform features labeled:
Internal combustion within the silencer reaches a peak of 123.6 dB.
The end cap exit event, consisting of bullet shock and the initial jet, results in a peak overpressure magnitude of 144.9 dB during the first shot and 146.7 dB during the second shot.
Major first-round-pop (FRP) divergence occurs relatively early and jetting reaches an initial peak magnitude of 144.5 dB.
Peak FRP occurs shortly thereafter at an amplitude of 145.1 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 moderate flow restriction (back pressure). Internal silencer design can significantly influence the measured timing and pressure amplitudes. Preliminary back pressure comparisons are shown in Section 6.132.3 of this review, with the PEW Science Back Pressure Metric, Ω [Pa-1]. Note that weapon system influence is a function of both Ω and early-time wave propagation factors which may be measured inside the system, in close proximity to the muzzle orifice. These factors include the so-called PEW Science alpha parameter; a subject of future research.
PEW Science Research Note 1: The BOSS Chairman, in this combustion regime, does possess some FRP that is noticeable to bystanders. The gas dynamics from the Chairman are characterized by flow that normalizes as the shot string continues, and subsequently begins to demonstrate erratic gas momentum accumulation later in the string. This phenomenon is shown in Figure 2a, above. After FRP, gas flow normalizes, but after Shot 3, more severe impulse is noted in early time. PEW Science postulates the silencer baffle porting structure within the Chairman may stagnate flow in some areas; more research is needed. Regardless of cause, the signature does have the potential to get more severe to bystanders later in the shot string.
PEW Science Research Note 2: The gross signature severity from the BOSS Chairman is on-par with that of the Rugged Suppressors Surge in its long configuration (6.22). This is notable due to the Chairman being approximately one inch shorter than that configuration of the Surge. However, the longer Surge does demonstrate more consistent combustion propagation, as well as less FRP to bystanders.
PEW Science Research Note 3: Reportedly, the baffle and porting geometry in the primary baffles of the BOSS Chairman share some design principles with that of a so-called Tesla Valve; a passive check-valve type geometry. PEW Science has not validated the efficacy of this design principle as applied to centerfire rifle silencer performance. However, it should be noted that because the Chairman possesses a traditional cone blast baffle that is not ported, early-time shock reflections still contribute to impulse accumulation inside the blast chamber and adjacent to the muzzle interface. It is likely that this early-time blast environment is more influential to weapon function than later time gas phase venting; this conclusion is supported by the PEW Science evaluation of the BOSS Silencers Guillotine (6.133) on the 5.56x45mm MK18 (6.133). In that study, the kinematics of the MK18 indicate probable early blast impulse accumulation influence (increased bolt carrier group speed).
Consistent with these measured pressure and impulse waveform features, the computed PEW Science Omega Metric is relatively moderate, placing the silencer in Omega Zone 6. Relative Suppression Rating and flow restriction (back pressure) data is presented in Section 6.132.2 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.
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.
6.132.3 Relative Suppression Rating and Back Pressure Comparisons (.30 Rifle Silencers)
The BOSS Chairman suppressor is intended to offer significant sound signature suppression. PEW Science has developed an empirical relation to quantify the back pressure (flow restriction) of silencers. Figure 5 and Figure 6 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 5 and Figure 6 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. Note that weapon system influence is also a function of early-time wave propagation factors which may be measured inside the system, in close proximity to the muzzle orifice. These factors include the so-called PEW Science Alpha parameter; a subject of future research.
- The Back Pressure Metric relations are most easily viewed on a logarithmic scale (See Figure 6).
Figure 5. 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 6, 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 6. 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 3. PEW Science Back Pressure Metric Omega Zones And Suppressed Weapon System Functional Descriptions
As stated above, weapon system influence is a function of both Ω and early-time wave propagation factors which may be measured inside the system, in close proximity to the muzzle orifice. These factors include the so-called PEW Science Alpha parameter; a subject of future research. The BOSS Silencers Chairman possesses a traditional symmetrical un-ported cone blast baffle. Shock reflections from such a baffle may influence weapon function differently than baffles of different shape and porting configurations.
The suppression performance of the Chairman on this platform, holistically, is best compared with the Rugged Suppressors Surge in its long configuration (6.22). This is notable due to the Chairman being approximately one inch shorter than that configuration of the Surge. The BOSS Chairman, like the Surge, has a 1.5-in diameter. Both those silencers eclipse the suppression performance of some other 1.5-in diameter silencers like the Dead Air Sandman-L (6.23) and Dead Air Sandman-Ti (6.19). The Chairman eclipses the performance of the Dead Air Nomad-Ti (6.44) on this platform as well, though the Chairman is longer and heavier. The Chairman also eclipses the sound suppression performance of the Q Thunder Chicken (6.20) on this platform, which is slightly longer than the Chairman, and larger in diameter.
PEW Science urges the reader not to misconstrue a low Omega metric with the mirroring of unsuppressed weapon function, nor a high Omega Metric with absolute use prohibition on semi-automatic systems. Each weapon system may experience varying sensitivity to different Omega Zones and users may exhibit varying preference for weapon system function and operability. The Zones are provided by PEW Science to assist the reader with determination of postulated applicability of silencer types, as some users may only have experience with certain silencers. The Omega Metric is one performance indicator; it allows overall flow rate phenomena to be categorized independently from sound signature suppression performance. Note that weapon system influence is also a function of early-time wave propagation factors which may be measured inside the system, in close proximity to the muzzle orifice.
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 PEW Science Suppression Rating computation considers all of these factors.
6.132.4 Review Summary: BOSS Silencers Chairman on a Savage Model 10 .308 with 20-in Barrel
When paired with the Savage M10 20” .308 and fired with Federal XM80, the BOSS Chairman with the direct thread mount, achieved a Suppression Rating™ of 43.5 in PEW Science testing. As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.
PEW Science Laboratory Staff Opinion:
The BOSS Silencers Chairman is a 30 caliber rifle silencer that possesses competitive suppression performance in its size class, on a centerfire rifle. Both stainless steel and titanium internal configurations of the silencer are offered, to meet weight requirements of the user. The BOSS Chairman, along with its smaller 5.56mm sister silencer, the Guillotine, possesses a modular rear mounting interface that may be used with a variety of mounting solutions and muzzle devices.
Reportedly, the baffle and porting geometry in the primary baffles of the BOSS Chairman share some design principles with that of a so-called Tesla Valve; a passive check-valve type geometry. PEW Science has not validated the efficacy of this design principle as applied to centerfire rifle silencer performance. However, it should be noted that because the Chairman possesses a traditional cone blast baffle that is not ported, early-time shock reflections still contribute to impulse accumulation inside the blast chamber and adjacent to the muzzle interface. It is likely that this early-time blast environment is more influential to weapon function than later time gas phase venting; this conclusion is supported by the PEW Science evaluation of the BOSS Silencers Guillotine on the 5.56x45mm MK18. In that study, the kinematics of the MK18 indicate probable early blast impulse accumulation influence (increased bolt carrier group speed).
The suppression performance of the Chairman on this platform, holistically, is best compared with the Rugged Suppressors Surge in its long configuration. This is notable due to the Chairman being approximately one inch shorter than that configuration of the Surge. The BOSS Chairman, like the Surge, has a 1.5-in diameter. Both those silencers eclipse the suppression performance of some other 1.5-in diameter silencers like the Dead Air Sandman-L and Dead Air Sandman-Ti. The Chairman eclipses the performance of the Dead Air Nomad-Ti on this platform as well, though the Chairman is longer and heavier. The Chairman also eclipses the sound suppression performance of the Q Thunder Chicken on this platform, which is slightly longer than the Chairman, and larger in diameter.
The rear mount threading of the BOSS Silencers Chairman 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 Chairman 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 included direct thread mount.
In this review, the Chairman 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.
