SSS.6.119 - Aero Precision Lahar-30L and the MK18 5.56x45mm Short Barrel Automatic AR15 Rifle
/Aero Precision Lahar-30L on the MK18 5.56x45mm AR15 with 10.3-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 hosts 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 Sound Signature Review contains single-test results using the Lahar-30L 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 6.119.1 contains the Lahar-30L test results and analysis.
Section 6.119.2 contains Suppression Rating comparisons of the Lahar-30L with dedicated 223 and 30 caliber silencers on the current market, including the Lahar-30, 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 6.119.3 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-30L achieved a composite Suppression Rating™ of 37.6 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
6.119.1 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 public 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
6.119.1.1 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 laboratory testing; the industry leader in public 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-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 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-30L 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Pressure Signature
Fig 1b. Aero Precision Lahar-30L 5.56x45mm NATO MK18 Automatic Rifle Sound Pressure Signature
Figure 2a. Aero Precision Lahar-30L 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature
Figure 2b. Aero Precision Lahar-30L 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature
The Aero Precision Lahar-30L is a midsize 30 caliber rifle silencer. Relative to dedicated 5.56x45mm silencers, the Lahar-30L may be considered “over-sized;” the silencer is slightly shorter than the Maxim Defense DSX (6.110) and similar in size to the short configuration of a Rugged Surge (6.22). It is longer than the Aero Precision Lahar-30 (6.116) that was previously evaluated by PEW Science in the 5.56x45mm combustion regime on the MK18. The suppression performance of the 30 caliber Lahar-30L, to bystanders, eclipses that of most other silencers tested on this platform, to date. However, its length should be noted.
Like the the Lahar-30, the Lahar-30L MK18 signature possesses first round pop (FRP) on this platform which is notated in both pressure space (Figure 1) and impulse space (Figure 2). However, the severity of FRP from the Lahar-30L is reduced when compared to that of the shorter Lahar-30. Both are 30 caliber silencers and over-bored for the 5.56x45mm cartridge. However, their designs result in gas propagation that is relatively delayed when compared to other 30 caliber silencers evaluated on the MK18 weapon system.
PEW Science Research Note 1: The Lahar-30L exhibits a reduced impulse accumulation rate when compared to that of the shorter Lahar-30 (Fig. 2b). The behavior is observed during FRP and significantly more pronounced during subsequent shots. As the two silencers possess identical proximal geometry, the rate decrease directly illustrates increased flow restriction (back pressure) of the Lahar-30L over that of the Lahar-30. The early time gas dynamics characterized by the so-called alpha parameter are identical, with the external gas momentum differing and characterized by the Omega research parameter. Keeping alpha constant allows for Omega scaling in accordance with the methodology outlined in Public Research Supplement 6.40. Although the silencer exhibits gross flow restriction in excess of many 5.56 bore silencers, early time gas dynamics not characterized by external wave momentum may result in similar weapon kinematics to some silencers with lower gross flow restriction.
PEW Science Research Note 2: The FRP divergence in the signature of the Aero Precision Lahar-30L is somewhat delayed (Fig. 1b). The FRP suppression performance of the Lahar-30L is on the MK18 is notable, as it was in the 7.62x51mm combustion regime in Review 6.112. The Aero Precision Lahar-30L outperforms the shorter Lahar-30 on the MK18 in FRP and in suppression performance, in general. The primary factor contributing to this overall higher suppression performance is the increased number of baffles. It was previously determined that the traditional curved-cone notched baffles of the Lahar series produce gas propagation behavior typical for the number employed in this design. The conclusion is further reinforced in this test.
PEW Science Research Note 3: The Aero Precision Lahar-30L exhibits notable signature consistency on the MK18 that is greater than observed in the test of the shorter version. The suppression performance for a 30 caliber silencer on the MK18, overall, is significant. However, the silencer is also 7.6-inches long in the tested configuration with a significant number of baffles for the envelope. Comparisons with shorter 30 caliber (over-bored) silencers may not be contextually appropriate, unless the user is mindful to note length, weight, and other parameters.
Despite the above contextual comparison caution, it should be noted that the Aero Precision Lahar-30L is shorter than the Surefire SOCOM762-RC2 (6.73) and significantly outperforms it in muzzle suppression. PEW Science Members are encouraged to utilize the Suppression Rating Parametric Visualization Tool in Section 7.2 to filter by weight and length parameters, for further contextual comparison.
It bears repeating that it is rare for 30 caliber silencers to exhibit significant combustion propagation consistency on the MK18 weapon system. Both the Lahar-30 (due to its design) and the longer Lahar-30L in this test report (due to its further increased length) are outliers joining the Dead Air Nomad-30 and CGS Helios QD. The previously expressed performance descriptions from Review 6.116 of the shorter Lahar-30 are repeated below:
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. The Lahar-30L continues this, as one would expect.
PEW Science Research Note 4: Again, it should be noted that although the Aero Precision Lahar-30L 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 75 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 can be 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-30L is 37.3 and the at-ear Suppression Rating is 24.0; different zones on the Suppression Rating Dose Chart. The higher early time flow rate of the 30 caliber Lahar-30L, 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, even despite its high degree of muzzle suppression. The signatures measured at the shooter’s ear are presented below.
6.119.1.2 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-30L 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Pressure Signature
Figure 3b. Aero Precision Lahar-30L 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Pressure Signature, Short Time Window
Figure 4a. Aero Precision Lahar-30L 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Impulse Signature
Figure 4b. Aero Precision Lahar-30L 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Impulse Signature Peaks
Like at the muzzle, the FRP from the Lahar-30L is measurable and visible in both pressure space and impulse space. However, unlike at the muzzle, the signature from the Lahar-30L, to the MK18 weapon operator, is not as consistent and is much more severe. This is largely due to its significant flow restriction (back pressure) driving ejection port pressure wave propagation.
PEW Science Research Note 8: There are several key indications that the ejection port signature is still producing meaningful operator hazard, even though the Lahar-30L is a 30 caliber rifle silencer. Over-bored silencers can still produce hazardous ejection port signatures on an untuned AR-15 weapon system.
Latent pressure pulses, along with latent negative phase (Fig. 3b) are one indication that ejection port pulse coalescence is becoming an operator risk factor. When examining the gas momentum transfer potential measured at the shooter’s ear (impulse, displayed in Figure 4), the positive phase accumulation after initial muzzle blast is significant. This type of impulse accumulation, measured at the MK18 operator location, typically manifests from severe ejection port pulse. Similar (but not identical) phenomena can be observed with other high backpressure silencers such as the the YHM Turbo T2 (6.98), SilencerCo Saker 556 (6.53), Otter Creek Labs Polonium (6.75), and others.
PEW Science Research Note 9: Interestingly, the impulse decay is sharp and consistent (Fig. 4a, 30 ms) with FRP differential manifesting later than typical. The high backpressure behavior of the Lahar-30L is not as severe to the operator as with the aforementioned silencers, and in conjunction with its significant muzzle signature suppression, the holistic signature to the operator is not as severe. Although the shooter’s ear Suppression Rating is 24.0, lower than the 30-Zone on the dose chart, its severity had the muzzle signature been more severe would have been much worse. This type of gas dynamics behavior, on the MK18, is indicative of a system that would benefit from “tuning” the weapon system such that less severe ejection port pulse may be generated. For typical benefits of such weapon modification, to operator signature, the reader may examine the test report of the Maxim Defense DSX SURG (6.111).
6.119.2 Suppression Rating Comparison (5.56x45mm from the MK18)
Figure 6 presents a comparison of the PEW Science Suppression Rating of the Aero Precision Lahar-30L 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-30L 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 during the entire time regime of weapon operation, including combustion, complete blowdown, and all mechanical operation, including the carrier group returning the battery, in the true free field. 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-30L eclipses most rifle silencers on the 5.56x45mm short barrel MK18 in muzzle (bystander) suppression performance, in PEW Science testing. Although the bystander performance of the Lahar-30L is eclipsed by that of the Maxim Defense DSX (6.110), the DSX is a larger silencer. The Otter Creek Labs Polonium (6.75) provides nominally higher muzzle suppression performance, but at the expense of more severe operator hazard on this untuned host weapon system. It is important to note that both the DSX and Polonium have smaller bores; the Lahar-30L is a 7.62mm rifle silencer, whereas the DSX is a dedicated 5.56mm silencer and the Polonium is a 6mm silencer.
The next closest muzzle suppression performance in the dataset is possessed by the Surefire SOCOM556-RC2 (6.52); another dedicated 5.56mm silencer. However, it exhibits both lower muzzle suppression and shooter’s ear suppression on this weapon system than the 30 caliber Lahar-30L. It is important to note that the SOCOM556-RC2 is significantly smaller than the Lahar-30L.
PEW Science Research Note 10: For a silencer with relatively high gross flow restriction and very high performance muzzle suppression, the shooter’s ear Suppression Rating of the Aero Precision Lahar-30L, on this weapon system, is somewhat as expected. The 30 caliber bore of the silencer does contribute to the somewhat reduced operator hazard when compared to the DSX, for example. However, it should be noted that the shorter Aero Precision Lahar-30 exhibits almost the same operator hazard on this untuned weapon system. This is a direct illustration of signature at the operator’s head being a function of both muzzle and ejection port signatures from the AR-15 weapon system. And, as a result, standoff of the silencer’s distal end, from the shooter’s head, plays a role. Muzzle suppression, standoff, and ejection port pulse all combine to create a sound field with the Lahar-30L and the Lahar-30 that are extremely holistically similar in hazard potential, to the weapon operator.
Silencers like the Aero Precision Lahar-30L, although reducing signature severity to bystanders, are not capable of reducing the severity of signature to the operator to the degree of silencers such as the HUXWRX FLOW 762 Ti (6.114). Without weapon tuning, most reciprocating rifles in typical configurations will produce hazardous ejection port signatures resulting from the degree of flow restriction possessed by the Lahar-30L. It is important to note that the technologies in the FLOW series, and other such silencers that exhibit high flow rate characteristics, are highly advanced.
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 systems and 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. Because the PEW Science Suppression Rating is a damage risk criterion (DRC), a lower Suppression Rating indicates a higher personnel hazard, in the true free field. Complete combustion dynamics and weapon mechanical operation are considered.
6.119.3 Review Summary: Aero Precision Lahar-30L 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-30L achieved a composite Suppression Rating™ of 37.6 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 should be considered full-size or oversized relative to dedicated 5.56mm silencers. The Lahar-30L possesses significant sound signature suppression performance in this combustion regime, possesses an Inconel blast baffle, may be used on machineguns, and has no barrel length restrictions. Although high performance, the Lahar-30L exhibits higher back pressure than the shorter Lahar-30 variants, which may require weapon tuning for optimal signature reduction or weapon operation.
The performance of the Aero Precision Lahar-30L, for a 30 caliber silencer of its size, is notable. However the current public dataset for such silencers on this host weapon is not yet robust. 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 relatively optimized for this combustion regime, even if it is potentially serendipitous.
Holistically, the performance of the Lahar-30L on the MK18 is best compared with the Maxim Defense DSX and the Otter Creek Labs Polonium, which are both smaller bore silencers. The Aero Precision Lahar-30L exhibits notable signature consistency on the MK18 that is greater than observed in the test of the shorter version. The suppression performance for a 30 caliber silencer on the MK18, overall, is significant. However, the silencer is also 7.6-inches long in the tested configuration with a significant number of baffles for the envelope. Comparisons with shorter 30 caliber (over-bored) silencers may not be contextually appropriate, unless the user is mindful to note length, weight, and other parameters. Despite this contextual comparison caution, it should be noted that the Aero Precision Lahar-30L is shorter than the Surefire SOCOM762-RC2 and significantly outperforms it in muzzle suppression.
In addition to its 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 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.
