SSS.6.112 - Aero Precision Lahar-30L and the Savage Model 10 PC .308

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Aero Precision Lahar-30L on a Savage Model 10 .308 with 20-in Barrel

The Lahar-30L is manufactured by Aero Precision. It is a 30 caliber centerfire rifle silencer, intended to suppress many cartridges with projectiles appropriately sized to travel through the bore, up to and including .300 Winchester Magnum, with no barrel length restrictions. It has a 1.58-inch diameter and is 7.3 inches in length. The rear of the silencer is threaded with the so-called HUB universal diameter and pitch, allowing the use of a variety of mounting solutions. With the included direct thread mount, the silencer’s length increases to 7.6 inches. The silencer is tubeless; the entirety of the silencer is constructed of 17-4 heat treated stainless steel, with the exception of the blast baffle, which is Inconel 718 alloy. The end cap is removable. As tested, the silencer weighs 18.9 ounces and the direct thread mount weighs 2.1 ounces, for a total system weight of 21 ounces. The Lahar-30L can be obtained from Silencer Shop.

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-Aero-050-001-23. Therefore, data pertaining to the Lahar-30L in this Sound Signature Review is published with the express written permission of Aero Precision, LLC.

This review contains single-test results using the Lahar-30L 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 6.112.1 contains the Lahar-30L test results and analysis.
  • Section 6.112.2 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 6.112.3 contains the review summary and PEW Science opinions.

Summary: When paired with the Savage M10 20” .308 and fired with Federal XM80, the Aero Precision Lahar-30L, mounted with the direct thread mount, achieved a Suppression Rating™ of 46.4 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

6.112.1 Aero Precision Lahar-30L Sound Signature Test Results

A summary of the principal Silencer Sound Standard performance metrics of the Lahar-30L is shown in Table 1. The data acquired 1.0 m (39.4 in) left of the muzzle is available for viewing to all. This is a members-only review and includes pressure and impulse waveforms measured at the shooter’s ear. PEW Science thanks you for your support; further testing, research, and development of PEW-SOFT and the Silencer Sound Standard is made possible by members like you!

 

Table 1. Aero Precision Lahar-30L Sound Metric Summary

 

6.112.1.1 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 Lahar-30L 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. Aero Precision Lahar-30L Bolt Action Rifle Muzzle Sound Pressure Signature

Fig 1b. Aero Precision Lahar-30L Bolt Action Rifle Muzzle Sound Pressure Signature, Short Time Window

Figure 2a. Aero Precision Lahar-30L Bolt Action Rifle Muzzle Sound Impulse Signature

Figure 2b. Aero Precision Lahar-30L Bolt Action Rifle Muzzle Sound Impulse Signature, Short Time Window

Figure 1b shows a 2 millisecond long portion of the first round sound pressure signature of the Aero Precision Lahar-30L as measured 1.0 m left of the muzzle. There are several significant waveform features labeled:

  1. Internal combustion within the silencer reaches a peak of 121.5 dB.

  2. The end cap exit event, consisting of bullet shock and the initial jet, results in a peak overpressure magnitude of 141.4 dB.

  3. There is significantly delayed FRP divergence; primary FRP jetting reaches and initial peak magnitude of 144.4 dB, finally reaching its maximum of 145.6 dB in later time.

This is a somewhat typical sequence observed when firing supersonic .308WIN ammunition from a bolt-action rifle with an attached silencer that exhibits relatively 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 6.112.3 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.

Although the above signature features are somewhat typical in general, the Aero Precision Lahar-30L presents relatively atypical suppression performance in this combustion regime, for a 30 caliber rifle silencer of its size. It is important to note that the Lahar-30L is approximately 7.6 inches long with its tested direct thread mount. The above signatures display behavior typically indicative of larger rifle silencers. The performance of the Lahar-30L on this platform, holistically, is best compared with the Thunder Beast ULTRA 9 (6.24) and the Otter Creek Labs PR30L (6.48), which are both over an inch longer.

PEW Science Research Note 1: As stated above, the performance of the Aero Precision Lahar-30L, for its size, is atypical. The internal baffle configuration of the tubeless silencer is not exceedingly complex, relative to other silencers examined in the Silencer Sound Standard research pedigree, to date. However, the configuration of the curved-cone baffles in the given tubeless volume of the Lahar-30L, appears to be highly optimized for this combustion regime. For a silencer of its length and diameter to produce the above measured signatures requires progressively delayed gas expansion that typically occurs with silencers approximately 8 inches in length and longer, especially with conventional baffle systems.

PEW Science Research Note 2: Figure 2b presents a relatively unique signature feature of the Lahar-30L in which secondary impulse accumulation is noted. From the initiation of primary jetting at a time of approximately 30.5 ms, the rate of impulse accumulation is relatively low. This delay in gas propagation is significant, not only in the time domain, but also in how it influences human inner ear response in the frequency domain. Internal PEW Science research conducted as part of this study indicates favorable inner ear response, of bystanders, to the Lahar-30L signature. This is particularly the case during the first shot. When compared to the Thunder Beast ULTRA 9 and the Otter Creek Labs PR30L, the first-round-pop (FRP) of the Lahar-30L, to bystanders, is shown to be less severe. Given the size of the silencer, this conclusion is significant.

PEW Science Research Note 3: The presence of a size-to-performance outlier in this combustion regime is not without precedent in the research pedigree, to date. One other example of a performance outlier previously examined and presented by PEW Science is the Liberty Precision Machine Anthem-S (6.79). At 7 inches long with its direct thread adapter, that silencer approaches the holistic suppression performance of the Aero Precision Lahar-30L, on this weapon system. The CGS Helios QD (6.13) is another example of a similarly sized performance outlier. However, is is very important to note that the Lahar-30L achieves its performance from considerably less complex internal geometry than both of those silencers, in a smaller diameter envelope, with only marginal length increase. The comparison of the Anthem-S, Helios QD, ULTRA 9, PR30L, and the Lahar-30L illustrates a pertinent case study in silencer design optimization for the 7.62x51mm supersonic cartridge. PEW Science urges the reader not to misconstrue 7.62x51mm performance on a bolt action weapon system with that of subsonic 300 BLK bolt action performance or even 5.56x45mm semiautomatic rifle performance. Each combustion regime, weapon system, and silencer combination possesses unique performance factors.

Consistent with these measured pressure and impulse waveform features, the computed PEW Science Omega Metric is relatively high, placing the silencer in Omega Zone 7. Relative Suppression Rating and flow restriction (back pressure) data is presented in Section 6.112.2 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. Despite the late-onset FRP divergence shown in the measured signatures, the progressively delayed nature of impulse accumulation results in significantly less severe FRP severity with the Lahar-30L, than typical. Masking of FRP in this way, to the inner ear response of bystanders, is notable.

6.112.1.2 SOUND SIGNATURES AT SHOOTER’S EAR

Real sound pressure histories from the same 5-shot test of the Lahar-30L suppressor acquired with PEW-SOFT at the shooter’s ear are shown below. Again, the waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science testing is 1.0 MS/s (1 MHz).

The primary sound signature pressure histories at the ear for all 5 shots are shown in Figure 3. The primary sound signature history is shown on the left. A zoomed-in timescale is displayed on the right, in the region of peak sound pressure for Shot 1 and Shot 2. The real sound impulse (momentum transfer potential) histories at the ear from the same 5-shot test are shown in Figure 4. Again, full and short timescales are shown.

Figure 3a. Aero Precision Lahar-30L Bolt Action Rifle Ear Sound Pressure Signature

Figure 3b. Aero Precision Lahar-30L Bolt Action Rifle Ear Sound Pressure Signature, Short Time Window

Figure 4a. Aero Precision Lahar-30L Bolt Action Rifle Ear Sound Impulse Signature

Figure 4b. Aero Precision Lahar-30L Bolt Action Rifle Ear Sound Impulse Signature, Short Time Window

The atypical FRP suppression performance of the Lahar-30L at the muzzle is mirrored at the shooter’s ear. Again, the progressively delayed impulse accumulation is noted in both pressure space (Fig. 3b) and impulse space (Fig 4b).

PEW Science Research Note 4: As noted in the preceding section, curved cone baffle geometry is not exceedingly complex. However, when optimized with both expansion volume and spacing, the baffle design can result in extremely high suppression efficiency for a given combustion regime. The Lahar-30L is an excellent example of this design optimization.

During the first shot, the performance of the Lahar-30L is extremely similar to that of the Otter Creek Labs PR30L, with regard to inner ear response. An in-depth comparison of the performance of these silencers, and the Thunder Beast ULTRA 9, will be published for PEW Science Members in the future, as a Research Supplement.

One hallmark of a high performance silencer on a bolt action weapon is significantly lower impulse accumulation in later time, measured at the shooter’s ear (ref. Figure 4). For a silencer of this length, to achieve both the consistency and amplitudes shown, is notable.

As typical, the overall sound signature measured at the shooter’s ear possesses significantly less amplitude in both the pressure and impulse regimes than the signature measured at the muzzle (refer to Table 1). Furthermore, the application of both pressure and impulse at the shooter’s ear is delayed when compared to the pressure and impulse at the weapon muzzle. The combination of varying amplitude and rise time to peak amplitude influences the response of the human ear.

It is extremely important to note that muzzle signature influences the signature to the weapon operator. This is a test on a bolt-action rifle. Similar jetting phenomenon measured at the muzzle propagates toward the shooter. The standoff of the endcap to the shooter, as well as angle of incidence of the pressure (blast) waves, result in exponential decay of hearing damage risk when compared to personnel adjacent to the muzzle.

6.112.2 Relative Suppression Rating and Back Pressure Comparisons (.30 Rifle Silencers)

The Aero Precision Lahar-30L suppressor is intended to offer significant sound signature suppression in a manageable size envelope, without significant regard to back pressure reduction. 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:

  1. 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.
  1. 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.
  1. 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.
  1. The theoretical lower limit of flow restriction, or so-called "zero back pressure" would be represented by the unsupressed state, Ω = 0 [Pa-1].
  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.
  1. 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 2. PEW Science Back Pressure Metric Omega Zones And Suppressed Weapon System Functional Descriptions

The performance of the Lahar-30L on this platform, holistically, is best compared with the Thunder Beast ULTRA 9 (6.24) and the Otter Creek Labs PR30L (6.48), which are both over an inch longer. Silencers that approach (but do not achieve) the supersonic 7.62x51mm suppression performance of the Lahar-30L include the Liberty Precision Machine Anthem-S (6.79), CGS Helios QD (6.13), and the Silencer Central Banish 30 Gold (6.69).

PEW Science Research Note 5: As previously noted, both the Anthem-S and Helios QD are slightly shorter than the Lahar-30L. The Banish 30 Gold, ULTRA 9, and PR30L are all longer. The Aero Precision Lahar-30L demonstrates one of the most significant examples of performance-based design optimization in the Silencer Sound Standard research pedigree, to date. Not only does it match the performance of longer silencers, but it also eclipses the performance of some of them. For example, the Lahar-30L is quieter to both the shooter, and to bystanders, than the Rugged Surge (6.22); a silencer that is 9 inches long. The Lahar-30L significantly outperforms the Dead Air Sandman-L (6.23), which is another 9 inch long silencer. The Lahar-30L also outperforms some silencers that are larger in diameter and length in this combustion regime, such as the Q Thunder Chicken (6.20). These comparisons are notable.

PEW Science Research Note 6: The Aero Precision Lahar-30L is in Omega Zone 7 (Figure 6), which indicates that it exhibits relatively high flow restriction. Interior expansion volume, coupled with the quantity and number of baffles, contribute to this lower flow rate.

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.

6.112.3 Review Summary: Aero Precision Lahar-30L on a Savage Model 10 .308 with 20-in Barrel

When paired with the Savage M10 20” .308 and fired with Federal XM80, the Aero Precision Lahar-30L, mounted with the direct thread mount, achieved a Suppression Rating™ of 46.4 in PEW Science testing. As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.

PEW Science Subjective Opinion:

The Aero Precision Lahar-30L is a mid-size 30 caliber precision rifle silencer that possesses significant sound signature suppression performance for its size, in this combustion regime. The silencer also possesses an Inconel blast baffle and may be used on machineguns, with no barrel length restrictions. The Lahar-30L represents one of the best examples of performance-based design optimization for this combustion regime in the research pedigree, to date. PEW Science 5.56 testing and analysis results with the Lahar-30L are forthcoming.

The performance of the Aero Precision Lahar-30L, for its size, is atypical. The internal baffle configuration of the tubeless silencer is not exceedingly complex, relative to other silencers examined in the Silencer Sound Standard research pedigree, to date. However, the configuration of the curved-cone baffles in the given tubeless volume of the Lahar-30L appears to be highly optimized for this combustion regime. For a silencer of its length and diameter to produce the above measured signatures requires progressively delayed gas expansion that typically occurs with silencers approximately 8 inches in length and longer, especially with conventional baffle systems.

Holistically, the performance of the Lahar-30L is best compared with the Thunder Beast ULTRA 9 and the Otter Creek Labs PR30L, which are both over an inch longer. The Lahar-30L is quieter to both the shooter, and to bystanders, than the Rugged Surge; a silencer that is 9 inches long. The Lahar-30L significantly outperforms the Dead Air Sandman-L, which is another 9 inch long silencer. The Lahar-30L also outperforms some silencers that are larger in diameter and length in this combustion regime, such as the Q Thunder Chicken. These comparisons are notable.

In addition to its size-to-performance factors, the Aero Precision Lahar-30L also possesses a feature not typically seen in some competing models. The silencer has an Inconel blast baffle, which may enable the silencer to exhibit significant durability under heavy firing schedules. However, PEW Science has not evaluated the durability of the Lahar-30L. In addition to high temperature durability, Aero Precision indicates the silencer may be used without barrel length restrictions for the cartridges on which it is rated. This performance factor may be attractive to some users due to the resulting high degree of utility; it also possesses a universal rear mounting system.

In this review, the Lahar-30L 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.