SSS.6.116 - Aero Precision Lahar-30 and the MK18 5.56x45mm Short Barrel Automatic AR15 Rifle

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Aero Precision Lahar-30 on the MK18 5.56x45mm AR15 with 10.3-in Barrel

The Lahar-30 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 5.8 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 6.1 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 14.7 ounces and the direct thread mount weighs 2.1 ounces, for a total system weight of 16.8 ounces. The Lahar-30 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-30 in this Sound Signature Review is published with the express written permission of Aero Precision, LLC.

This Sound Signature Review contains single-test results using the Lahar-30 mounted with its direct thread mount on the MK18 Automatic AR15 rifle, chambered in 5.56x45mm NATO with a 10.3-inch barrel. Federal XM193 55gr ammunition was used in the test. The standard PEW Science MK18 test host weapon system is described in Public Research Supplement 6.51.

  • Section 6.116.1 contains the Lahar-30 test results and analysis.

  • Section 6.116.2 contains Suppression Rating comparisons of the Lahar-30 with dedicated 223 and 30 caliber silencers on the current market, including the HUXWRX Flow 762 Ti, Maxim Defense DSX, Thunder Beast Dominus, KAC 5.56 QDC, CGS SCI-SIX, Dead Air Nomad-30, YHM Turbo T2, Dead Air Sandman-S, HUXWRX FLOW 556k, Energetic Armament ARX, KAC QDSS-NT4, Rugged Razor556, Otter Creek Labs Polonium and Polonium-K, Surefire SOCOM556-RC2, HUXWRX HX-QD 556 and HX-QD 556k, Q Trash Panda, CGS Helios QD, SilencerCo Saker 556, Rugged Razor762, and others.

  • Section 6.116.3 contains the review summary and PEW Science subjective opinions.

Summary: When paired with the 10.3-in barrel MK18 and fired with Federal XM193, the Aero Precision Lahar-30 achieved a composite Suppression Rating™ of 29.5 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

6.116.1 Aero Precision Lahar-30 Sound Signature Test Results

A summary of the principal Silencer Sound Standard performance metrics of the Lahar-30 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-30 Sound Metric Summary

 

6.116.1.1 SOUND SIGNATURES AT THE MUZZLE

Real sound pressure histories from a 6-shot test acquired with PEW-SOFT™ are shown below. Six cartridges were loaded into the magazine, the fire control group positioned to single-shot, and the weapon was fired until the magazine was empty and the bolt locked back on the follower of the empty magazine. Only five shots are considered in the analysis. The signatures of Shot 6 are displayed in the data presentation but are not included in the analysis to maintain consistency with the overall PEW Science dataset and bolt-closing signatures. 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 6 shots with the Lahar-30 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 6-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-30 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Pressure Signature

Fig 1b. Aero Precision Lahar-30 5.56x45mm NATO MK18 Automatic Rifle Sound Pressure Signature

Figure 2a. Aero Precision Lahar-30 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature

Figure 2b. Aero Precision Lahar-30 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature

The Aero Precision Lahar-30 is a relatively compact 30 caliber rifle silencer. Relative to dedicated 5.56x45mm silencers, the Lahar-30 may be considered “full-size.” It contains six baffles and is shorter than the longer Aero Precision Lahar-30L (6.112) that was previously evaluated by PEW Science in the 7.62x51mm combustion regime on a bolt-action rifle. MK18 5.56x45mm testing and analysis reporting of the longer Lahar-30L performance by PEW Science is forthcoming.

The Lahar-30 MK18 signature possesses first round pop (FRP) on this platform which is notated in both pressure space (Figure 1) and impulse space (Figure 2). Although the Lahar-30 is a 30 caliber silencer and over-bored for the 5.56x45mm cartridge, its quantity of baffles, interstitial expansion volumes, and baffle design, result in gas propagation that is relatively delayed when compared to other 30 caliber silencers evaluated on the MK18 weapon system. Note the lower impulse accumulation rate (Fig. 2b); the silencer exhibits gross flow restriction on par with that of some 5.56 bore silencers.

PEW Science Research Note 1: The FRP divergence in the signature of the Aero Precision Lahar-30 is immediate (Fig. 1b). And, the divergence is significant until momentum accumulation decay (Fig. 2b, 31.8 ms). Although the FRP suppression performance of the longer Lahar-30L on the 7.62x51mm platform was high, the FRP suppression performance of the shorter Lahar-30 on the short barrel 5.56x45mm MK18 is less robust. The factors contributing to this lower relative suppression performance during the first shot include the reduced number of baffles, coupled with the specific baffle design and over-bore for the platform. The traditional curved-cone notched baffles of the Lahar series produce gas propagation behavior typical for the number employed in this design.

PEW Science Research Note 2: Despite the typical FRP performance of such a design on this platform, the Aero Precision Lahar-30 does exhibit notable signature consistency as well as competitive suppression performance for a 30 caliber silencer on the MK18, overall. Typically, over-bored silencers on the MK18 exhibit erratic signatures, due to the severe secondary combustion from the short 10.3-in barrel. In the MK18 testing of the Dead Air Nomad-30 (6.100), it was noted that silencers with advanced coaxial baffle elements, like the Nomad-30 and the CGS Helios QD (6.66), typically outperform more simple 30 caliber silencers on the MK18, with regard to consistency. Such inconsistent and inefficient performance is characterized in measured impulse signatures from over-bored silencers in test reports featuring the Rugged Razor762 (6.58), the Energetic Armament ARX (6.82); the Rugged Razor556 (6.76), the Q Trash Panda (6.61), and the Dead Air Sandman-S (6.92). For the Aero Precision Lahar-30 to employ a simple over-bored baffle geometry, and still produce a signature consistency on-par with that of 30 caliber silencers like the Nomad-30 and Helios QD, is notable.

PEW Science Research Note 3: The Aero Precision Lahar-30 is only 6.1 inches long with its direct thread mount. This is notable, considering its performance on the MK18 as a 30 caliber rifle silencer. For example, the Lahar-30 outperforms the Q Trash Panda on the MK18; a 30 caliber rifle silencer that is almost an inch longer. The Lahar-30 also outperforms the Dead Air Nomad and CGS Helios QD, which are both over an inch longer. Interestingly, the only 30 caliber rifle silencer in the current dataset that eclipses the overall suppression performance of the Lahar-30 on the MK18 is the HUXWRX FLOW 762 Ti (6.114), which is also longer.

PEW Science Research Note 4: It should be noted that although the Aero Precision Lahar-30 is a 30 caliber rifle silencer, it produces significantly higher back pressure on the MK18 than silencers exhibiting very high flow rates, such as the HUXWRX (OSS) HX-QD 556 (6.54), HUXWRX (OSS) HX-QD 556k (6.64), the HUXWRX FLOW 556K (6.83), and the HUXWRX FLOW 762 Ti (6.114).

PEW Science Research Note 5: As in all semiautomatic AR15 weapon testing, a second pressure pulse originates from the ejection-port signature of the weapon and it occurs early enough in time such that its waves coalesce with that of the muzzle signature. However, in late time (at approximately 77 ms in Figure 1a) the mechanical noise of the bolt closing is observed. The pressure signature of Shot 6 does not display this event due to the bolt remaining open after the sixth and final round is fired from the magazine.

PEW Science Research Note 6: The closing time of the MK18 bolt is directly related to the flow restriction of a silencer for a given weapon system. PEW Science has determined bolt closing time variation from the unsuppressed state to be a reliable indicator of silencer back pressure, with strong correlation with the PEW Science Back Pressure Metric, Omega. However, PEW Science has also determined that the indicator is unreliable upon upper receiver fouling. Sound signatures are not influenced by this fouling, as these kinematics occur in late time, after gas venting to atmosphere. Momentum transfer, weapon condition (upper receiver fouling), and other factors, can significantly influence bolt closing time. PEW Science urges the reader to exercise extreme caution if using the published bolt closing time to make determinations regarding silencer flow restriction (back pressure) or weapon system kinematics. This type of calculation may provide erroneous results, as the weapon condition at the time of each test is not published data. The time-scale duration showing bolt closing time is only published by PEW Science such that the signature data pedigree may be verified.

The shape, timing, and magnitudes of the early-time pressure pulses and overall shape of the impulse waveforms measured at the muzzle, from shot-to-shot, are relatively consistent. The consistency of the waveform amplitudes highlight the silencer’s overall sound performance consistency at the muzzle after the FRP, as well as the relative consistency of the tested automatic rifle firearm configuration.

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 Research Note 7: Note that the muzzle Suppression Rating of the Aero Precision Lahar-30 is 27.3 and the at-ear Suppression Rating is 24.2; the same zone on the Suppression Rating Dose Chart. The higher flow rate of the 30 caliber Lahar-30, relative to some dedicated bore 5.56 silencers, does assist with reducing ejection port signature, but it is not high enough to significantly decrease the overall severity of the signature to the shooter on the standard MK18 weapon system. The signatures measured at the shooter’s ear are presented below.

6.116.1.2 SOUND SIGNATURES AT SHOOTER’S EAR

Real sound pressure histories from the same 6-shot test 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 6 shots are shown in Figure 3. The primary sound signature history is shown in Figure 3a. A zoomed-in timescale is displayed in Figure 3b, in the region of peak sound pressure for Shots 1 and 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-30 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Pressure Signature

Figure 3b. Aero Precision Lahar-30 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Pressure Signature, Short Time Window

Figure 4a. Aero Precision Lahar-30 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Impulse Signature

Figure 4b. Aero Precision Lahar-30 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Impulse Signature Peaks

Like at the muzzle, the FRP from the Lahar-30 is measurable and visible in both pressure space and impulse space. Overall, the signature from the Lahar-30, to the MK18 weapon operator, is relatively consistent.

The relative timing and amplitude of FRP impulse accumulation indicates that the ejection port signature is still producing meaningful operator hazard, even though the Lahar-30 is a 30 caliber rifle silencer. Over-bored silencers can still produce hazardous ejection port signatures on an untuned AR-15 weapon system. As has been discussed in previous publications, this phenomenon is again described in the research note below.

PEW Science Research Note 8: As was discussed in the test report of the Maxim Defense DSX SURG (6.111), there are waveform features in Figure 4 pertinent to the behavior of silencers on the standard MK18, in general. The timing and accumulation of FRP impulse, relative to that of other shots, can provide insight into which phenomena are muzzle driven or ejection port driven in an AR-15 system, even with limited transducer fielding and measurement points. Typically, with an extremely “low back pressure” silencer, the shooter’s ear signature on the standard MK18 will exhibit front-loaded impulse accumulation during FRP; this is because the ejection port pulse is not dominating the signature, so the primary nested FRP accumulation from the muzzle appears earlier in time. With an extremely “high back pressure” silencer, the opposite occurs, with the shooter’s ear signature exhibiting back-loaded impulse during FRP on this weapon system. With the Lahar-30, note the back-loaded FRP impulse at the shooter’s ear (Fig. 4b). For a case of front-loaded impulse, see the aforementioned DSX SURG article. For an example of balanced impulse loading, see the aforementioned articles examining the HUXWRX FLOW series.

PEW Science Research Note 9: The FRP to the weapon operator on the MK18, with the Lahar-30, is more severe than it is to bystanders. This phenomenon is due to the muzzle FRP occurring from a relatively short silencer. In general, severe muzzle signature components occurring in close relative proximity to the operator result in increased hazard. Further standoff from the pressure origin (using a longer barrel, for example) would lessen FRP relative severity to the operator. As described in Research Note 8, it is important to note that FRP is a muzzle driven phenomenon.

Despite the higher backpressure resulting in severe ejection port signature, as well as the more severe FRP in closer proximity to the shooter due to silencer’s short length, the waveform features measured at the shooter’s ear are still not as severe as those measured with the Otter Creek Labs Polonium (6.75) or SilencerCo Saker 556 (6.53). This is one indicator that the Lahar-30 is increasing flow restriction, but not to the degree of a dedicated bore silencer. All three silencers lack internal porting; the primary difference is due to gas expansion volume and larger bore. As discussed in Research Note 2, it is atypical for a traditional 30 caliber rifle silencer to achieve this holistic performance on the MK18, especially in a 6 inch length envelope.

6.116.2 Suppression Rating Comparison (5.56x45mm from the MK18)

Figure 6 presents a comparison of the PEW Science Suppression Rating of the Aero Precision Lahar-30 to that of other rifle silences on the MK18 automatic AR15 rifle. The standard PEW Science MK18 test host weapon system is described in Public Research Supplement 6.51.

Figure 6. Suppression Rating Comparisons of the Aero Precision Lahar-30 and other silencers, Using PEW-SOFT 5.56x45mm Supersonic Test Data and PEW Science Analysis

Figure 6 presents detailed PEW Science Suppression Ratings, computed at the muzzle and ear, for the listed silencers. The Suppression Rating is a holistic parameter that captures human inner ear damage risk potential from a measured impulsive overpressure signature. The parameter may be used with the dose chart at the beginning of this report.

From the above data, it can be concluded that the Aero Precision Lahar-30 outperforms most 30 caliber rifle silencers on the 5.56x45mm short barrel MK18, in PEW Science testing. Although the performance of the Lahar-30 is eclipsed by that of the HUXWRX FLOW 762 Ti (6.114), the technology in the FLOW series is highly advanced and the FLOW 762 Ti is longer than the Lahar-30. For a traditional curved-cone baffle silencer like the Lahar-30 to outperform the suppression of 30 caliber silencers like the Dead Air Nomad-30 (6.100) and CGS Helios QD (6.66) on the MK18, is notable. The Aero Precision Lahar-30 outperforms the Dead Air Sandman-S (6.92) on this platform significantly, and is almost an inch shorter than the Sandman-S. Both silencers use traditional baffle technology; the Lahar-30 provides a shorter, lighter, and higher performing solution.

PEW Science Research Note 10: Interestingly, the Aero Precision Lahar-30 performs similarly, holistically, to the YHM Turbo T2 (6.98). A key difference in the performance of the two silencers is the flow restriction (back pressure). With its larger bore, the Lahar-30 is able to reduce operator hazard on the untuned MK18 weapon system, by reducing the severity of the ejection port signature. It does this despite its relatively short length and closer proximity of muzzle pressure origin to the operator’s head. This phenomenon is discussed in further detail in the previous section. At the shooter’s ear, on the untuned MK18, the Aero Precision Lahar-30 produces a signature similar in severity to that of the CGS SCI-SIX (6.101). Users should note that due to the disparity in muzzle suppression between the two silencers on this platform, as well as the nature of the untuned MK18 test host, the comparison of the signature produced by the two silencers may be significantly influenced by surrounding environments and weapon parameters differing from the tested configuration. The influence of nearby reflecting surfaces on small arm sound signatures is a subject of future PEW Science research.

The Aero Precision Lahar-30 also exhibits an overall signature severity, to the shooter and bystanders, that is similar to that of the KAC QDSS-NT4 (6.78) on this weapon system. Although the behavior of this legacy silencer is much different than that of the Lahar-30, the hearing damage risk potential from the two silencers is comparable on the standard MK18.

PEW Science Research Note 11: Another 30 caliber silencer that is almost an inch longer than the Lahar-30 is the Thunder Beast Dominus (6.105). The Dominus produces a more severe hazard to both bystanders and to the weapon operator than does the Aero Precision Lahar-30. As the two silencers both use relatively simple baffles, a comparison case study using the two silencers may provide insight to system designers regarding the efficacy of different baffle technology. Another particularly useful comparison is that of the Lahar-30 performance with that of the Q Trash Panda (6.61). The Trash Panda is larger than the Lahar-30 in both length and diameter. Both silencers provide comparable suppression performance on this weapon system.

As shown in Figure 6, the Suppression Rating at the shooter’s ear may be significantly influenced by the ejection port signature from the MK18; all other things equal. For details on performance increases that are possible when “tuning” an AR-15 weapon system for a silencer, please see Review 6.111. It is important to note that not all silencers will possess a significant increase in shooter’s ear Suppression Rating from weapon tuning. Signature at the operator’s head is a function of both muzzle and ejection port signatures from the AR-15 weapon system.

Like the larger Lahar-30L, the Aero Precision Lahar-30 demonstrates the performance of an optimized traditional baffle design. For a conventional baffle 30 caliber silencer to outperform most other 30 caliber silencers on the market on this weapon system, and do so in such a short size envelope, is notable.

6.116.3 Review Summary: Aero Precision Lahar-30 on the MK18 5.56x45mm AR15 with 10.3-in Barrel

When paired with the 10.3-in barrel MK18 and fired with Federal XM193, the Aero Precision Lahar-30 achieved a composite Suppression Rating™ of 29.5 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-30 is a compact 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-30 represents one of the best examples of performance-based design optimization for a conventional baffle 30 caliber rifle silencer on the 5.56x45mm MK18 weapon system, to date.

The performance of the Aero Precision Lahar-30, 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-30 appears to be highly optimized for this combustion regime. For a silencer of its length and diameter to produce the above measured signatures is notable, especially for a 30 caliber rifle silencer using a conventional baffle system.

The Aero Precision Lahar-30 outperforms most 30 caliber rifle silencers on the 5.56x45mm short barrel MK18, in PEW Science testing. Although the performance of the Lahar-30 is eclipsed by that of the HUXWRX FLOW 762 Ti, the technology in the FLOW series is highly advanced and the FLOW 762 Ti is longer than the Lahar-30. For a traditional curved-cone baffle silencer like the Lahar-30 to outperform 30 caliber silencers like the Dead Air Nomad and CGS Helios QD on the MK18, is notable. The Aero Precision Lahar-30 outperforms the Dead Sandman-S on this platform significantly, and is almost an inch shorter than the Sandman-S. Both silencers use traditional baffle technology; the Lahar-30 provides a shorter, lighter, and higher performing solution.

The Aero Precision Lahar-30 performs similarly, holistically, to the YHM Turbo T2. A key difference in the performance of the two silencers is the flow restriction (back pressure). With its larger bore, the Lahar-30 is able to reduce operator hazard on the untuned MK18 weapon system by reducing the severity of the ejection port signature. It does this despite its relatively short length and closer proximity of muzzle pressure origin to the operator’s head.

The Aero Precision Lahar-30 also exhibits an overall signature severity, to the shooter and bystanders, that is similar to that of the KAC QDSS-NT4 on this weapon system. Although the behavior of this legacy silencer is much different than that of the Lahar-30, the hearing damage risk potential from the two silencers is comparable on the standard MK18. Another particularly useful comparison is that of the Lahar-30 performance with that of the Q Trash Panda. The Trash Panda is larger than the Lahar-30 in both length and diameter. Both silencers provide comparable suppression performance on this weapon system.

In addition to its size-to-performance factors, the Aero Precision Lahar-30 (like other silencers in the Lahar family) 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-30. 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-30 performance metrics depend upon suppressing a supersonic centerfire rifle cartridge on a short barrel gas-operated rifle, which is an incredibly difficult 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 5.56x45mm cartridge are significant; the measured pressure and impulse magnitudes, and their durations, illustrate this fact. Silencer performance on automatic (reciprocating) rifles depends on many factors. Weapon configuration may significantly influence total suppressed small arm system performance.

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.