SSS.6.114 - HUXWRX FLOW 762 Ti and the MK18 5.56x45mm Short Barrel Automatic AR15 Rifle
/HUXWRX FLOW 762 Ti on the MK18 5.56x45mm AR15 with 10.3-in Barrel
The FLOW 762 Ti is designed and manufactured by HUXWRX. It is a 30 caliber centerfire rifle silencer, intended to suppress many cartridges with projectiles appropriately sized to travel through the bore, with no barrel length restrictions. It has a 1.8-inch diameter and is 6.75 inches long. The silencer mounts to proprietary HUXWRX LH-threaded taper-mount muzzle devices. With the muzzle device installed, the total length of the system is 6.9 inches. The entirety of the silencer is DMLS (3D-printed) Grade 5 Titanium. The silencer weighs 11.3 ounces and the Flash Hider-QD 556 taper mount weighs 3.3 ounces, for a total system weight of 14.7 ounces, as tested. The FLOW 762 Ti 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-HUX-054-001-23. Therefore, data pertaining to the FLOW 762 Ti in this Sound Signature Review is published with the express written permission of HUXWRX Safety Co. LLC.
This Sound Signature Review contains single-test results using the FLOW 762 Ti mounted with the Flash Hider-QD 556 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 6.114.1 contains the FLOW 762 Ti test results and analysis.
Section 6.114.2 contains Suppression Rating comparisons of the Flow 762 Ti with dedicated 223 and 30 caliber silencers on the current market, including the 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 6.114.3 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 HUXWRX FLOW 762 Ti achieved a composite Suppression Rating™ of 35.7 in PEW Science testing.
As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.
The supersonic 7.62x51mm performance of the HUXWRX FLOW 762 Ti is detailed in Sound Signature Review 6.113, in which it achieved a Suppression Rating of 41.6.
Relative Suppression Rating Performance is Summarized in SSS.7 - PEW Science Rankings
6.114.1 HUXWRX FLOW 762 Ti Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the FLOW 762 Ti 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. HUXWRX FLOW 762 Ti Sound Metric Summary
6.114.1.1 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 FLOW 762 Ti 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. HUXWRX FLOW 762 Ti 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Pressure Signature
Fig 1b. HUXWRX FLOW 762 Ti 5.56x45mm NATO MK18 Automatic Rifle Sound Pressure Signature
Figure 2a. HUXWRX FLOW 762 Ti 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature
Figure 2b. HUXWRX FLOW 762 Ti 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature
As in the test of the previous generation HUXWRX (OSS) silencers and the new generation HUXWRX FLOW 556k (6.83), the gas jetting from the HUXWRX FLOW 762 Ti is significantly faster than observed from high back pressure silencers like the Maxim Defense DSX (6.110), Otter Creek Labs Polonium (6.75) and the SilencerCo Saker 556 (6.53). It also flows significantly faster than the Surefire SOCOM556-RC2 (6.52). Holistically, the overall flow rate of the FLOW 762 Ti is slightly faster than that of the CGS SCI-SIX (6.101).
PEW Science Research Note 1: When compared to the previous HX-QD generation, the updated Flow-Through technology in the HUXWRX FLOW series exhibits internal gas propagation with measurably longer duration. This behavior was observed in the longer blow down time exhibited during 7.62x51mm combustion in the .308 Bolt Gun Test of the FLOW 762 Ti (6.113) and is also displayed in Figure 1a, above. For reference, the reader may refer to the behavior exhibited by the HUXWRX (OSS) HX-QD 556 on the MK18 (6.54), in which a significantly shorter blow down time was measured. Furthermore, the lower gas momentum accumulation is also evidenced by limited rarefaction persistent throughout the shot string (Figure 1b). Finally, the rate of rise to peak positive phase impulse (Figure 2b) of the FLOW 762 Ti is lower than the other Flow-Through silencers tested on the MK18. The net result of this behavior, with the FLOW technology specifically, is a longer effective contact time of combustion gases with the silencer internals. With the testing of the FLOW 762 Ti, which is over-bored for the 5.56x45mm MK18, this behavior has now been shown to occur independently of bore size, which is a significant technological advancement.
PEW Science Research Note 2: Despite the longer duration gas blow down from the FLOW 762 Ti and it’s higher PEW Science Omega Metric, which is a measure of overall gross flow rate, the FLOW series possesses early-time gas dynamics in close proximity to the muzzle orifice that influence wave propagation significantly less than conventional rifle silencers. These factors include the so-called PEW Science Alpha parameter; a subject of future research. This is important to note, because although the gross flow rate of the FLOW 762 Ti is only slightly lower than the CGS SCI-SIX, for example, its influence on MK18 weapon function is much different. Weapon function, along with blow back and other system phenomena, are functions of both Alpha and Omega. The FLOW 762 Ti, and the FLOW technology in general, is able to keep combustion gasses in the system for a longer duration, while still maintaining a very high flow rate. This is highly atypical.
PEW Science Research Note 3: The above noted internal gas propagation duration phenomena are of particular importance when comparing the performance of the FLOW 762 Ti to the FLOW 556k on the MK18 weapon system. Both silencers exhibit extremely high flow rates relative to typical rifle silencers; however, operator hazard is a function of both ejection port signature and muzzle signature. Furthermore, the relative timing of these signature components, as well as complex waveform parameters such as frequency and phase, influence inner ear response.
Advanced signature analysis of the FLOW 556k is available to PEW Science Members; further FLOW 762 Ti analysis will be published at a later date. The FLOW 556k induces a more “boomy” signature than the FLOW 762 Ti on this weapon system; the shorter length and shorter flow paths in the FLOW 556k produce a higher gross flow rate and both contribute to this phenomenon. Accordingly, the FLOW 762 Ti is able to contain combustion gasses for a longer duration in its geometry. As discussed in the bolt action test report, this behavior allows for a greater degree of gas expansion and heat transfer over the time regime of blow down, which both contribute to suppression performance increases. However, the slight decrease in gross flow rate, even with favorable early-time gas dynamics, produce an ejection port signature that combines with the muzzle signature components to produce a holistic signature at the shooter’s ear that is slightly less favorable to the weapon operator on the untuned MK18 weapon system with the FLOW 762 Ti than with the FLOW 556k. Though the performance differential is not significant, it is measurable. PEW Science data and analysis is therefore consistent with HUXWRX internal weapon kinematics testing, which indicates that the FLOW 762 Ti induces a slightly higher bolt velocity on the standard MK18 than does the FLOW 556k. This comparison of test data and analysis, from two independent sources, not only illustrates the crucial importance of ejection port signature to operator hazard on an untuned AR15, but also provides a significant validation case study for efficacy of research published in The Silencer Sound Standard, as well as for internal HUXWRX research and development.
PEW Science Research Note 4: The holistic suppression performance of the FLOW 762 Ti on this weapon system eclipses that of the FLOW 556k. This overall conclusion is notable given that the FLOW 762 Ti is over-bored for the cartridge. Public testing of over-bored silencers on the 5.56x45mm MK18 weapon system by PEW Science has demonstrated typical inefficiencies, such as erratic flow rate. Such inefficiency characterized in measured impulse signatures from over-bored silencers may be examined in test reports featuring products such as 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).
Internal PEW Science research indicates that previous generations of Flow-Through technology, as implemented in the HX-QD series, lose efficiency when used in an over-bored application. For the technology in the FLOW 762 Ti to not lose efficiency on a 5.56x45mm host weapon, particularly on a short barrel, is significantly notable.
PEW Science Research Note 5: The FLOW 762 Ti exhibits less significant first round pop (FRP) to bystanders on this platform than does the FLOW 556k, in accordance with PEW Science inner ear modeling. The ancillary combustion during Shot 1 is observed in both pressure space (Figure 1b) and impulse space (Figure 2a). Another notable trait of the updated Flow-Through technology in both the FLOW 556k and FLOW 762 Ti is the maintained suppression efficiency throughout the shot string, when compared to that of the previous HX-QD generation. In the .308 bolt action test report with the FLOW 762 Ti, this test report, as well as the 5.56x45mm MK18 test report with the FLOW 556k, impulse accumulation from later shots does increase in amplitude. However, unlike as is the case with the HX-QD technology, the FLOW technology results in a consistent throttling of accumulation rate. It is this change in gas dynamics that is one of the key differentiators between the two technology generations and one of the factors responsible for significant holistic suppression performance increases. The FLOW series is able to maintain a high flow rate while increasing the duration for which the gas occupies the silencer, when compared to previous generations of the Flow-Through technology. The silencers in the HUXWRX FLOW series continue to demonstrate some of the most advanced gas dynamics, and associated performance, quantified in the Silencer Sound Standard research pedigree.
PEW Science Research Note 6: 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 90 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 7: 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 8: Note that the muzzle Suppression Rating of the HUXWRX FLOW 762 Ti is 33.9 and the at-ear Suppression Rating is 29.8; almost the same zone on the Suppression Rating Dose Chart. Unlike many rifle silencers, the high flow rate of the HUXWRX FLOW 762 Ti, coupled with its above-average muzzle suppression, is extremely beneficial to the sound signature at the shooter’s ear on the standard MK18 weapon system. The back pressure of the FLOW 762 Ti is low, and the muzzle signature is suppressed adequately enough, that the weapon operator is subjected to less significant hearing damage risk. The HUXWRX FLOW 762 Ti possesses the second highest Suppression Rating at the shooter’s ear on the untuned standard MK18 weapon system than any silencer tested by PEW Science, to date; it is only bested by the HUXWRX FLOW 556k. The signatures measured at the shooter’s ear are presented below.
6.114.1.2 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.HUXWRX FLOW 762 Ti 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Pressure Signature
Figure 3b. HUXWRX FLOW 762 Ti 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Pressure Signature, Short Time Window
Figure 4a. HUXWRX FLOW 762 Ti 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Impulse Signature
Figure 4b. HUXWRX FLOW 762 Ti 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Impulse Signature Peaks
The waveforms measured at the shooter’s ear offer several insights into gross MK18 system behavior with the FLOW 762 Ti, and also provide additional validation for the conclusions presented in the preceding section.
Overall, the signatures are characterized by relatively low amplitude, expedient decay, and notable consistency. The FLOW 762 Ti not only provides high suppression performance; it does it repeatedly throughout the shot string.
The longer blow down time (longer duration of internal gas propagation through the silencer) is again observed, this time in the later time jetting noted in Figure 3b. Typically, an extremely high flow rate silencer will exhibit extremely low amplitude in the pressure regime prior to ground reflection. The FLOW 762 Ti does exhibit low amplitude, but not as low as does the FLOW 556k on this weapon system.
The relative timing and amplitude of FRP impulse accumulation indicates that the ejection port signature is still producing meaningful operator hazard. This phenomenon is described in the research note below.
PEW Science Research Note 9: 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 AR15 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. In the case of the HUXWRX FLOW series, the FRP impulse accumulation is nominally balanced.
When comparing the signatures from the FLOW 762 Ti to that from the FLOW 556k, there are late-time accumulation features noted in the FLOW 762 Ti signatures that suggest a slightly higher muzzle contribution to the nested signature in late time. This slight imbalance, though nuanced, is consistent with the silencer’s slightly longer blow down time, slightly higher induced bolt velocity on the weapon system measured by HUXWRX, and the slightly lower shooter’s ear Suppression Rating on this weapon system. PEW Science postulates that even nominal tuning of the MK18 weapon system may nullify the influence of this behavior. The FLOW technology, even when incorporated into a larger envelope, continues to demonstrate extreme efficiency on semiautomatic weapon systems, with regard to holistic signature suppression and operator hazard reduction.
PEW Science Research Note 10: There is a significant performance factor exhibited by the FLOW 762 Ti, for the weapon operator, relative to that of the FLOW 556k. The FLOW 762 Ti masks additional FRP hazard to the shooter on the untuned MK18. For a high flow rate silencer to accomplish this, with overall significant suppression performance, is not only extremely notable, but also unprecedented in PEW Science research.
6.114.2 Suppression Rating Comparison (5.56x45mm from the MK18)
Figure 6 presents a comparison of the PEW Science Suppression Rating of the HUXWRX FLOW 762 Ti 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 HUXWRX FLOW 762 Ti 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 aforementioned low back pressure of the HUXWRX FLOW 762 Ti results in significant sound signature hazard reduction at the shooter’s ear on the MK18 weapon system. This performance occurs despite the silencer’s longer blow down time, which also contributes to significant sound signature hazard reduction to bystanders. For a high flow rate silencer to achieve these levels of hazard reduction to both the bystander, and to the shooter, on an untuned MK18 weapon system, is extremely notable. Once again, the updated Flow-Through technology in the HUXWRX FLOW series of silencers demonstrates unprecedented hazard reduction efficacy for the platform.
PEW Science Research Note 11: For context, the hazard to the weapon operator with the FLOW 762 Ti is characterized by a shooter’s ear Suppression Rating of 29.8; this level of hazard reduction is only bested by another HUXWRX silencer; the FLOW 556k, which exhibits an even higher flow rate. Technical comparison of the behavior of these two systems is provided in the preceding sections of this report. Typically, silencers with such high flow rates (low back pressure) exhibit muzzle Suppression Ratings that are more severe (higher hazard to bystanders). However, the HUXWRX FLOW 762 Ti, on the 10.3-inch MK18 weapon system, does not. In addition to providing significant hazard reduction to the weapon operator, the FLOW 762 Ti provides significant hazard reduction to bystanders, relative to other silencers evaluated in the Silencer Sound Standard pedigree. The FLOW 762 Ti provides equivalent hazard reduction to bystanders as the CGS SCI-SIX (6.101) on this platform, which is a highly advanced silencer. Furthermore, the FLOW 762 Ti matches the Composite Suppression Rating of the Surefire SOCOM556-RC2 (6.52) on the MK18, which is a silencer specifically designed for the platform and it does so with a shooter’s ear hazard reduction that significantly outperforms that of the Surefire silencer.
PEW Science Research Note 12: The HUXWRX FLOW 762 Ti, holistically, outperforms most silencers tested on the MK18 by PEW Science, to date, in signature hazard reduction. Due to the breadth of the Silencer Sound Standard testing and analysis pedigree, the reader is encouraged to examine the spectrum over which suppression performance on the MK18 has been demonstrated. There exist silencers evaluated on the 5.56x45mm short barrel rifle platform that have significantly lower performance. Because the PEW Science Suppression Rating is a damage risk criterion (DRC), a lower Suppression Rating indicates a higher personnel hazard in the free field. Therefore, silencers such as the Energetic Armament ARX (6.82), the Rugged Razor762 (6.58), and WARCOMP-equipped Surefire silencers, are postulated to be more hazardous to the unprotected ear than silencers like the HUXWRX FLOW 762 Ti. To iterate, the Suppression Rating is a DRC - it is not a subjective quantity; it is an objective quantification of hearing damage risk potential.
PEW Science Research Note 13: The larger bore of the HUXWRX FLOW 762 Ti, prior to this testing and analysis, was postulated to be a performance detriment on 5.56x45mm weapons systems. This postulation by PEW Science was based on internal research with the previous generation HX-QD series, testing and analysis of other 30 caliber silencers on the platform, and the available evidence in the pedigree research, to date. With the publication of this report, the FLOW 762 Ti demonstrates the first example of a silencer that exhibits both high performance and flow rate, with significant over-bore, in the state of practice. Coupled with the published performance research on a .308 bolt action rifle (6.113), the HUXWRX FLOW 762 Ti again illustrates a significant technological performance gap compared to other 30 caliber silencers that is considered by PEW Science to be generational. Similar conclusions were published by PEW Science in the FLOW 556k MK18 test report (6.83).
To put the above conclusion in further context, the Dead Air Nomad is considered to be an advanced supersonic rifle silencer. The HUXWRX FLOW 762 Ti matches the performance of the Dead Air Nomad series on a 7.62x51mm bolt action weapon, and significantly exceeds the performance of the Nomad series on a semiautomatic 5.56x45mm short barrel rifle. For a Flow-Through silencer to achieve this performance is extremely notable. Other 30 caliber silencers are also significantly outperformed in suppression performance by the FLOW 762 Ti in multiple combustion regimes and on multiple platforms, including the Q Trash Panda, the Thunder Beast Dominus, and the Dead Air Sandman-S.
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. Silencers such as the FLOW series from HUXWRX may require minimal, if any, weapon tuning to reduce operator hazard, when compared to conventional silencers. Specific weapon system parameters will dictate modification efficacy.
6.114.3 Review Summary: HUXWRX FLOW 762 Ti 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 HUXWRX FLOW 762 Ti achieved a composite Suppression Rating™ of 35.7 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 HUXWRX FLOW 762 Ti is a relatively compact and lightweight 30 caliber machine gun rated rifle silencer that exhibits significant back pressure reduction and sound signature suppression performance, for its size. Its sound suppression performance on a short barrel 5.56x45mm rifle is significant. Notably, its sound suppression performance at the shooter’s ear on a .308 bolt action rifle is competitive with that of advanced conventional baffle silencers. The silencer is constructed of 3D-printed Grade 5 Titanium and represents one of the most advanced systems evaluated by PEW Science, to date.
Like the previous generation HX-QD 762 series, the FLOW 762 Ti contains a series of ported helical baffle components within the silencer core. Functionally, the core uses geometric features to induce turbulent flow, while early and continuously routing combustion gasses into annular space for down-stream venting to atmosphere. The distal end of the silencer contains significant exit flow area around its outer circumference. The sound suppression efficiency of this design is directly proportional to cartridge pressure, flow velocity, and duration. The FLOW technology, taking advantage of additive manufacturing (3D-printing), is more advanced than that of the previous generation HX-QD series and the measured performance illustrates this advancement.
The sound suppression performance of the HUXWRX FLOW 762 Ti on a bolt action weapon is highly atypical for a silencer with such a high flow rate. The reader is encouraged to examine that evaluation in the previous article.
On the 5.56x45mm MK18 short barrel rifle, the suppression performance of the FLOW 762 Ti is extremely high. For a high flow rate silencer to achieve these levels of hazard reduction to both the bystander, and to the shooter, on an untuned MK18 weapon system, is extremely notable. Once again, the updated Flow-Through technology in the HUXWRX FLOW series of silencers demonstrates unprecedented hazard reduction efficacy for the platform.
Typically, silencers with such high flow rates (low back pressure) exhibit muzzle Suppression Ratings that are more severe (higher hazard to bystanders). However, the HUXWRX FLOW 762 Ti, on the 10.3-inch MK18 weapon system, does not. In addition to providing significant hazard reduction to the weapon operator, the FLOW 762 Ti provides significant hazard reduction to bystanders, relative to other silencers evaluated in the Silencer Sound Standard pedigree. The FLOW 762 Ti provides equivalent hazard reduction to bystanders as the CGS SCI-SIX on this platform, which is a highly advanced silencer. Furthermore, the FLOW 762 Ti matches the Composite Suppression Rating of the Surefire SOCOM556-RC2 on the MK18, which is a silencer specifically designed for the platform and it does so with a shooter’s ear hazard reduction that significantly outperforms that of the Surefire silencer.
As was noted in the evaluation of the FLOW 556K, the FLOW technology continues to represent the best balance of Suppression Rating and back pressure reduction in the supersonic flow regime measured by PEW Science.
One consequence of high mass flow rate through a silencer is a potential increase in flash signature. However, the FLOW series silencers possesses flash-hiding features on their endcaps and increased internal surface roughness through additive manufacturing, compared with the previous generation HX-QD series. PEW Science postulates that these design factors influence flash suppression performance, but has not yet evaluated the flash hiding performance of the FLOW 762 Ti. Qualitative measurements of flash using the FLOW 556K on short barrel 5.56x45mm weapons has indicated adequate flash suppression for the author.
The left-hand (LH) threaded taper mounts from HUXWRX are simple to operate. They may be installed on the weapon system with an adjustable wrench; the mount bodies, themselves, serve as wrench-flats. Newer iterations of the mounts include additional wrench flat features. As the silencer is LH threaded to the mount, the mount is easily removed from the silencer, should the mount be detached from the weapon while still in the silencer. One can then tighten the entire assembly to the conventionally right-hand (RH) threaded barrel muzzle, and continued RH tightening will subsequently loosen the silencer from the mount. Although proper mount installation torque mitigates such a solution from being absolutely necessary, this mechanical feature is welcome for practicality. The distal vents of the silencer produce thrust which actively tighten the silencer to the mount, during use. This feature is unique to HUXWRX rifle silencers; PEW Science confirms that this feature demonstrates efficacy in the field.
PEW Science has not evaluated the durability of the FLOW silencer system(s) on semiautomatic or automatic host weapons. Note that the nature of low flow restriction (low back pressure) silencers may positively influence durability, as the silencers are designed to vent more quickly than traditional designs, relative to the time regime of combustion. As the FLOW 762 Ti is 3D-printed in its entirety, PEW Science postulates that it may exhibit increased durability when compared to the previous HX-QD generation. These phenomena are subjects of further research. HUXWRX reports this postulation to be correct, in accordance with their internal testing.
In this review, the FLOW 762 Ti 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.
