SSS.6.55 - Dead Air Nomad-L and the Savage Model 10 PC .308 (Free Version)
/Dead Air Nomad-L on a Savage Model 10 .308 with 20-in Barrel
The Nomad-L is designed by Dead Air. 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 8.5 inches in length when using the direct-thread adapter. The user may choose to use other Dead Air or third-party mount adapters compatible with the 1.375”-24tpi system. The silencer is tubeless; the baffles are constructed of 17-4 stainless steel, with a removable endcap constructed of Grade 5 titanium. The silencer weighs 18.8 ounces with the direct thread mount, as tested. The Nomad-L can be obtained from Silencer Shop.
Note that the Nomad-L is also offered in a titanium version (the Nomad-LT). While similar, the sound signatures of the Nomad-L and Nomad-LT are not identical; the Nomad-L exhibits slightly higher sound signature suppression performance on this platform, in accordance with PEW Science testing and analysis.
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 or any test data that references a product designed or manufactured by a PEW Science Corporate Member Supporter not publicly listed contains this disclosure. Although not displayed in the public Client and Corporate Member list, the engineering division of Dead Air Armament (a division of Sound Moderation Technologies; dba Dead Air Silencers) was a supporting Corporate Member of PEW Science at the time of this article’s publication. Dear Air’s previous corporate support notwithstanding, the testing and analysis production for this Sound Signature Review was funded wholly by PEW Science and all data is owned by PEW Science, LLC.
This review contains single-test results using the Nomad-L mounted 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 test.
- Section 6.55.1 contains the Nomad-L test results and analysis.
- Section 6.55.2 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 6.55.3 contains the review summary and PEW Science opinions.
Summary: When paired with the Savage M10 20” .308 and fired with Federal XM80, the Dead Air Nomad-L mounted with the direct thread adapter, achieved a Suppression Rating™ of 52.0 in PEW Science testing.
Relative Suppression Rating Performance is Summarized in SSS.7 - PEW Science Rankings
Test data for the compact version(s) of this silencer, the Dead Air Nomad and Nomad Ti, can be found in Sound Signature Reviews 6.43 and 6.44, respectively.
6.55.1 Dead Air Nomad-L Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Nomad-L 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.Dead Air Nomad-L Sound Metric Summary
6.55.1.1 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 2.7 millisecond long portion of the first round sound pressure signature of the Nomad-L as measured 1.0 m left of the muzzle. There are five significant waveform features labeled:
Firing system manipulation is measured to exhibit a peak amplitude of 108.0 dB.
Peak amplitude of internal combustion within the silencer reaches 126.3 dB.
The endcap exit event results in an initial overpressure peak magnitude of 140.3 dB.
The first primary jet builds to an amplitude of 142.3 dB (peak FRP).
Secondary jetting results in a latent peak overpressure amplitude of 136.7 dB.
This is a somewhat typical sequence observed when firing supersonic .308WIN ammunition from a bolt-action rifle with an attached silencer that exhibits high flow restriction (back pressure). Internal silencer design can significantly influence the measured timing and pressure amplitudes. Preliminary back pressure comparisons are shown in Section 6.55.2 of this review, with the PEW Science Back Pressure Metric, Ω [Pa-1].
Fig 1. Dead Air Nomad-L First Round Bolt Action Rifle Muzzle Sound Pressure Signature, 20-MAR-2021
The waveform shown in Figure 1 possesses characteristics very similar to the FRP signature of silencers exhibiting flow restriction (back pressure) in PEW Science Omega Zone 7, such as the CGS Hyperion (Review 6.27), the Thunder Beast ULTRA 9 (Review 6.24), and the Otter Creek Labs PR30L (Review 6.48). Features of sound signatures in this flow regime are characterized by highly decoupled bullet exit events with extreme post-exit amplitude suppression. This behavior is directly indicative of the extreme flow restriction of such silencers. At the muzzle, the Dead Air Nomad-L is slightly quieter than the CGS Hyperion on this platform; the severity of both sound signatures being significantly similar in overall loudness to the human inner ear. In-depth comparisons of the sound signatures from silencers like the Nomad-L, Hyperion, ULTRA 9, and PR30L are the subject of a future PEW Science Member Research Supplement. It is important to note that user perception of the comparison between Nomad-L and Hyperion sound signatures is highly dependent upon shooter variables; (e.g. stock position on cheek, previous inner ear damage, etc) due to the sound signature severity being very similar between the two silencers on this test platform. Both silencers are noticeably quieter than the Thunder Beast ULTRA 9 and Otter Creek Labs PR30L on this platform. The Nomad-L and CGS Hyperion represent the highest performing supersonic centerfire rifle silencers tested by PEW Science, to date.
The sound signature of the Dead Air Nomad-L shares notable similarities with that of the shorter Dead Air Nomad-30 (Review 6.43) and Dead Air Nomad-Ti (Review 6.44), specifically in the early-time combustion signature prior to bullet exit (Feature 2 in Figure 1, above). The internal flow path geometry and wall thickness of the Nomad series is postulated to contribute significantly to this phenomenon. While not a significant signature contribution on this test platform, the influence of this behavior in lower amplitude combustion regimes (e.g. subsonic cartridge suppression) is the subject of ongoing PEW Science research.
Another notable similarity between the Nomad-L and Nomad-Ti signature is that of a pronounced early-time negative phase; one indicator of potential lower flow restriction (lower back pressure). However, unlike the Nomad-30 and Nomad-Ti, the Nomad-L possesses more baffles in its longer envelope and the negative phase behavior is short-lived; the silencer continues to restrict flow well into the cartridge combustion duration, and as a result possesses the highest PEW Science Omega Metric of any centerfire rifle silencer tested by PEW Science. The back pressure generation of the Nomad-L is postulated to be significant; see Section 6.55.2 of this review.
Like all silencers in the Dead Air Nomad series, the Nomad-L design possesses stepped-cone baffles with coaxial elements similar to elements of original SWR Omega geometry and elements of modern CGS Hyperion technology; the presence of which relieves localized high pressure stagnation and allows for more efficient supersonic gas flow suppression for a given silencer volume. Comprehensive Suppression Rating comparisons are provided in Section 6.55.2.
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 internal silencer combustion and endcap exit event between all 5 shots during the test. These waveform feature consistencies in both 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 0.525 milliseconds (525 microseconds) and the total timescale in Figure 2b is only 0.11 milliseconds (110 microseconds). PEW-SOFT provides a sampling point every microsecond and the individual data points are shown in Figure 2b to illustrate this.
Fig 2a. Dead Air Nomad-L Bolt Action Rifle Muzzle Sound Pressure Early-Time Peaks, 20-MAR-2021
Fig 2b. Dead Air Nomad-L Bolt Action Rifle Muzzle Sound Pressure Shot 1 Peak, 20-MAR-2021
The primary sound signature pressure histories for all 5 shots with the Nomad-L 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.
Fig 3a. Dead Air Nomad-L Bolt Action Rifle Muzzle Sound Pressure Signature, 20-MAR-2021
Fig 3b. Dead Air Nomad-L Bolt Action Rifle Muzzle Sound Pressure Signature, Short Time Window, 20-MAR-2021
Figure 4a. Dead Air Nomad-L Bolt Action Rifle Muzzle Sound Impulse Signature, 20-MAR-2021
Figure 4b. Dead Air Nomad-L Bolt Action Rifle Muzzle Sound Impulse Signature, Short Time Window, 20-MAR-2021
The Nomad-L exhibits FRP measured at the muzzle that is perceptible to bystanders. The FRP is highlighted in the pressure regime (Figure 3) and significantly in the impulse regime (Figure 4). Shortly after a time of approximately 30.75 ms in the above figures, the impulse accumulation in the Nomad-L sound signature is measured to drop, prior to continued building in the positive phase. It is at this time that the performance deviation from the shorter silencers in the Nomad series is most significant.
PEW Science Research Note 1: Given the above measured impulse accumulation phenomena, PEW Science postulates that the Nomad baffle technology exhibits significant flow restriction when utilized above a certain amount of baffles (at scale). While this Nomad baffle configuration exhibits similar supersonic sound suppression performance to a CGS Hyperion, this scalability produces performance at the cost of back pressure. While the two silencers exhibit some similarities in design and performance, it is this measured behavior that is one of the most significant differentiators between the two technologies.
PEW Science Research Note 2: The Otter Creek Labs PR30L (Review 6.48) is another silencer that exhibits high performance sound signature suppression on this platform; it’s sound signature is similar in severity to that of the Thunder Beast ULTRA 9. These silencers, and the CGS Hyperion, all produce impulse accumulation rates that are relatively consistent (the PR30L being the most erratic). The Nomad-L produces an impulse signature that is highly unique; the accumulation delay until a time of approximately 31 ms after the drop at 30.75 ms in Figure 4 is unprecedented in full size silencers, but consistent with the shorter Nomad-30 and Nomad-Ti of the same baffle design. Comparing the behavior of the four silencers with the highest supersonic suppression performance (Hyperion, Nomad-L, PR30L, and ULTRA 9) highlights the thresholds of performance that can be achieved with each technology. The performance compromises to achieve such sound suppression are noteworthy; flow restriction may manifest differently depending upon baffle scalability. PEW Science postulates that this holistic design reality may influence the future of silencer development. PEW Science further postulates that simply adding baffles to a design may not result in holistic performance gains comparable to that which may be achievable with advanced additive manufacturing.
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. Silencers like the Nomad-L are in a different performance class than others on the market. The sound signature suppression performance of silencers like the Dead Air Nomad-L and CGS Hyperion is extreme; PEW Science urges the user to also consider the resulting flow restriction (back pressure) for particular weapon system application. This performance characteristic is discussed in Section 6.55.2.
6.55.2 Relative Suppression Rating and Back Pressure Comparisons (.30 Rifle Silencers)
The Nomad-L suppressor is intended to maximize sound signature suppression. 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 endcap. PEW Science highly recommends data acquisition in accordance with The Silencer Sound Standard.
- Omega Zones are presented in Table 2, 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 to 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 Nomad-L is very similar in Suppression Rating to the CGS Hyperion (Review 6.27) on this test platform. The Nomad-L exhibits higher flow restriction (back pressure) than the Hyperion. Interestingly, the increase in back pressure of the Nomad-L does not pay dividends in increased sound signature suppression performance. Adding baffles to the Nomad or Nomad-Ti design to create a Nomad-L increases the suppression performance, but the flow restriction (back pressure) increases accordingly, and possibly at a greater rate than with other baffle designs. As previously discussed in Section 6.55.1.1 of this review, flow restriction may manifest differently depending upon baffle scalability. PEW Science postulates that this holistic design reality may influence the future of silencer development. To iterate, PEW Science further postulates that simply adding baffles to a design may not result in holistic performance gains comparable to that which may be achievable with advanced additive manufacturing.
PEW Science Research Note 3: PEW Science urges the reader not to misconstrue 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.
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; the Nomad-L and CGS Hyperion represent the highest performing supersonic centerfire rifle silencers tested by PEW Science, to date.
6.55.3 Review Summary: Dead Air Nomad-L on a Savage Model 10 .308 with 20-in Barrel
When paired with the Savage M10 20” .308 and fired with Federal XM80, the Dead Air Nomad-L mounted with the direct thread adapter, achieved a Suppression Rating™ of 52.0 in PEW Science testing.
PEW Science Subjective Opinion:
The Dead Air Nomad-L is a full-size .30 rifle silencer that exhibits extreme sound signature reduction in the supersonic flow regime, while possessing a modular rear mount capability. Note that the Nomad-L is also offered in a titanium version (the Nomad-LT). While similar, the sound signatures of the Nomad-L and Nomad-LT are not identical; the Nomad-L exhibits higher sound signature suppression performance on this platform; users should note that the supersonic suppression and back pressure characteristics of the Nomad-L highlighted in this review represent upper bound performance of the Nomad family of silencers. The back pressure generation of the Nomad-L is significant.
The Nomad-L contains broad and flattened baffles that have more aggressive step geometry than the Nomad-30 (1st Gen). The baffles have ports utilizing an outer baffle annulus. Functionally, the design results in highly efficient management of supersonic flow by preventing a significant degree of high pressure stagnation in a way that does not significantly increase flow restriction until a certain amount of baffles are used; the Nomad-L uses enough baffles that the back pressure generation is significant. Nonetheless, the balance of gas redistribution allows the Nomad technology to perform well with high pressure centerfire rifle cartridges but also excel at the suppression of lower pressure flow; the balance of which is atypical. Subsonic performance data of the Nomad-L is the subject of a future PEW Science publication.
The Nomad-L meets or exceeds the muzzle Suppression Rating of the CGS Hyperion on this platform, which is significant. The Suppression Ratings at the shooter’s ear of the two silencers are extremely similar on this platform; user perception of the comparison between Nomad-L and Hyperion sound signatures is highly dependent upon shooter variables; (e.g. stock position on cheek, previous inner ear damage, etc).
Interestingly, the method by which the Nomad-L achieves its high performance sound signature suppression may be detrimental to ancillary performance factors, such as flow restriction (back pressure). Unlike the CGS Hyperion, the Nomad-L is created from “scaling” a Nomad silencer with the addition of baffles; flow restriction may manifest differently depending upon baffle scalability. PEW Science postulates that this holistic design reality may influence the future of silencer development. The data and analysis presented in this review indicates that the addition of baffles, without other significant design changes, may increase suppression performance, but increase flow restriction unnecessarily.
The rear mount threading of the Nomad series is 1.375”-24tpi; relatively common in today’s rifle silencer market. As a result of this common modular interface, a plethora of mounting systems may be used. The performance of the Nomad-L 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. The mount may be removed with included spanner tools from Dead Air; both the mount and the silencer body possess wrench indexing features. The silencer endcap is also removable; the use of endcaps with varying orifice diameter is possible, along with a recoil reducing so-called “E-Brake;” which is an endcap assembly that vents gas radially to counteract rifle recoil kinematics. PEW Science has not evaluated the efficacy of the E-brake system nor its influence on sound suppression performance with the Nomad-L.
The silencer is also offered in a titanium version (the so-called “LT”). The Ti version may be attractive to some users due to the weight reduction. Durability of the steel silencer is expected to be higher than that of the Ti silencer. PEW Science has not evaluated the durability of the steel or titanium Nomad silencer system(s) on semiautomatic or automatic host weapons. As discussed above, the Nomad-L is slightly quieter than the Nomad-LT on this platform.
In this review, the Nomad-L 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.
