SSS.6.238 - PTR VENT 1 and the Q mini FIX 300 BLK Subsonic (Free Version)

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PTR VENT 1 on a Q mini FIX 300 BLK with 8-in Barrel

The VENT 1 is designed and manufactured by PTR Industries. It is a 30 caliber centerfire rifle silencer, intended to suppress the 7.62x51mm NATO cartridge. The VENT 1 has a 1.74-inch diameter and is 8.75 inches long with no mount. The silencer may be attached to a variety of weapon systems depending on the user’s choice of mount; the included 5/8-24tpi direct thread mount increases the system length to 9.1 inches. Other mounting options are possible due to the rear of the silencer body being HUB compatible (1.375-24 tpi threading). The entirety of the VENT 1 structure is monolithic and constructed from 3D Printed Titanium. The silencer weighs 13.1 ounces and the included direct thread mount weighs 2.3 ounces, for a total system weight of 15.4 ounces, as tested. The VENT 1 can be obtained from Silencer Shop.

Silencer Hazard Map:

The predicted personnel hazards generated by the tested weapon system in this report, in the free field, are shown in the adjacent Silencer Hazard Map. Click or tap the Map to enlarge.  Please reference Silencer Hazard Map Brief 8.1.35 for further details.  The PEW-SOFT HD Blast Hazard Prediction Tool and Hazard Mapper is presented in Report 8.1.1.

Previous Evaluation:

The VENT 1 was also evaluated in the supersonic ammunition combustion regime on a .308 bolt-action rifle.  That testing and analysis is presented in Report 6.160.  The behaviors observed in that test program are contextually relevant to the observations and conclusions presented in this report.

PTR VENT 1 8-in barrel 300 BLK Subsonic Bolt-Action Free Field Hazard Map Produced by PEW-SOFT HD Blast Hazard Prediction Tool using PEW Science Test Data

PEW Science is an independent private testing laboratory and also hosts the world’s only independent public 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 analysis production for this Sound Signature Review was funded in part by PEW Science Project PEW-PTR-084-001-24. Therefore, data pertaining to the VENT 1 in this Sound Signature Review is published with the express written permission of PTR Industries Inc.

This Sound Signature Review contains single-test results using the PTR VENT 1 with its direct-thread mount on the Q mini FIX bolt action rifle, chambered in 300 BLK with an 8-inch barrel. Discreet Ballistics 190gr ammunition was used in the test.

  • Section 6.238.1 contains the PTR VENT 1 test results and analysis.

  • Section 6.238.2 contains Suppression Rating comparisons with selected .30 rifle silencers in the subsonic 300 BLK ammunition combustion regime.

  • Section 6.238.3 contains the review summary and PEW Science laboratory staff technical opinions.

Summary: When paired with the Q mini FIX 8-in 300 BLK and fired with Discreet Ballistics 190gr Subsonic Target ammunition, the PTR VENT 1 with its direct-thread mount achieved a composite Suppression Rating™ of 81.5 in PEW Science testing.

The 20-in barrel bolt-action supersonic .308 performance of the PTR VENT 1 with its direct-thread mount system is detailed in Sound Signature Review 6.160, in which it achieved a composite Suppression Rating of 57.3.

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.

6.238.1 PTR VENT 1 Sound Signature Test Results

A summary of the principal Silencer Sound Standard performance metrics of the PTR VENT 1 is shown in Table 1. The data acquired 1.0 m (39.4 in) left of the muzzle is available for viewing to all. The data acquired 0.15 m (6 in) right of the shooter’s ear is only available to membership supporters of PEW Science and the Silencer Sound Standard. You can support public PEW Science testing, research, and development with a membership, here. State-of-the-art public firearm sound signature testing and research conducted by PEW Science is supported by readers like you.

 

Table 1. PTR VENT 1 Sound Metric Summary

 

6.238.1.1 SOUND SIGNATURES AT THE MUZZLE

Real sound pressure histories from a 5-shot test acquired with PEW-SOFT™ are shown below. The waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science laboratory sound signature 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 recognized 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 are shown in Figure 1a. A zoomed-in timescale displays early time phenomena in Figure 1b, for the first two shots. 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. PTR VENT 1 Bolt Action 300 BLK Muzzle Sound Pressure Signature

Fig 1b. PTR VENT 1 Bolt Action 300 BLK Muzzle Sound Pressure Signature, Short Time Window

Figure 2a. PTR VENT 1 Bolt Action 300 BLK Muzzle Sound Impulse Signature

Figure 2b. PTR VENT 1 Bolt Action 300 BLK Muzzle Sound Impulse Signature

This report summarizes the low pressure subsonic 300 BLK testing of the PTR VENT 1. The silencer has also been evaluated suppressing longer duration higher pressure combustion on a .308 bolt-action rifle in Report 6.160.

As previously presented in the aforementioned high pressure evaluation, the PTR VENT 1 displays highly unusual and advanced signature suppression characteristics. The iteration of PTR Purposely Induced Porosity (PIP) technology in the VENT 1 allows significant and continuous heat transfer and external momentum propagation beginning very early in the first pressure stage response of the silencer all the way through complete blowdown. The resulting measured signatures present with a characteristic “smoothness” and “continuity” devoid of abrupt jet components or transient flow changes observed from several other designs.  Interestingly, this behavior is not limited to full rifle cartridge suppression.  Some early hypotheses and debate regarding the behavior of the PIP technology in the VENT 1 postulated that full high amplitude pressure saturation (an internal propagation of high amplitude blast overpressure through a significant part of the lattice structure) would be required to gain significant suppression efficiency and take adequate advantage of the technology. On the contrary, that initial hypothesis appears to be incorrect. The blast test data measured in this study displays indications that not only does the hybrid design implementation of the PIP technology in the VENT 1 scale its performance into lower combustion pressure and duration regimes, but several of the same behavioral factors remain with its low pressure subsonic 300 BLK suppression that were observed in its high pressure 7.62 NATO suppression.

PEW Science Research Note 1:  One of the very unique signature “fingerprint” features of the VENT 1 silencer is its propensity to allow external blast load propagation to build appreciable momentum very early in time and control it to such a degree that the totality of external signature forms a complete, uninterrupted “continuum” through the entire blowdown phase. Most silencers of this suppression performance class possess distinct pressure staging and the transition through those stages results in transient shifts and pronounced delays throughout blowdown. It is the increase in transient impulsivity that can many times contribute significantly to increased suppressed signature severity.  The VENT 1 smooths all transitions between each stage of primary flow (ref. 6.160, Research Note 1).  The following observations in the above test data once again illustrate this behavior:

  1. Very low amplitude free field blast overpressure with relatively expedient blowdown (Fig. 1a).

  2. Highly controlled jetting components for a significant portion of the initial positive phase momentum accumulation (Fig. 1b).

  3. First-round-pop (FRP) is effectively masked; its divergence in both overpressure and impulse accumulation rate is nominal, particularly considering the observed amplitude range (Fig. 2a).

  4. Primary phase impulse accumulation initiates at higher amplitude than typical and remains extremely stable and consistent (Fig. 2b).

PEW Science Research Note 2: Each of the above four observations were also noted in the previous supersonic high pressure evaluation of the VENT 1. Congruent behavior across significantly different combustion input regimes demonstrates superior scaling of the PIP technology in this implementation.  It is very important to note that the VENT 1 is a hybrid design and it does contain some conventional baffle elements. The effectiveness of those elements, in conjunction with the PIP tech throughout both the baffle structure and annular flow paths, is maximized.

PEW Science Research Note 3: Another very unique behavioral characteristic of the VENT 1, brought about by its specific implementation of the PIP technology, becomes much more apparent with subsonic suppression and is related to the early momentum propagation described in Research Note 1 and observed in the blast impulse histories. There is a nesting of two significant but different phenomena that occur in early time from the silencer.  The PIP lattice allows for blast loads to propagate through the silencer in very early time. Simultaneously there is significant internal blast load propagation into the first expansion chamber of the silencer, where PIP is not utilized. The acoustic resonance from this chamber nests with initial blast pressure egress from the lattice.  The same thing happens when the silencer is used to suppress supersonic rifle cartridges, but the difference here is that because the overall pressure amplitude of the subsonic 300 BLK cartridge is so low, the initial momentum contribution from these events is higher in a relative sense. Two practical consequences of this behavior are:

  1. Peak positive phase impulse accumulation is higher than one may expect given the degree of overall signature severity.

  2. Areas in close proximity to the blast chamber will be subjected to increased signature that is actually meaningful in a relative sense, due to the extreme suppression of the global signature.

A succinct demonstration of consequence (2) is displayed visually in the Silencer Hazard Map at the beginning of this report. Note the hazard source located near the end of the barrel (the entrance to the silencer). Also note there is a hazard source located at the weapon chamber (though closed, a bolt-action weapon chamber still emits audible signature as the blast pressure waves propagate through the steel). These ancillary sources are always present; when suppressed weapon systems become exceptionally quiet, the source contributions to observed signature become more significant. These phenomena are large drivers of the limits of operator (Shooter’s Ear) Suppression Rating on this weapon system.  Even as the bystander (Muzzle) Suppression Rating of the PTR VENT 1 reaches a staggering 81.0 on this weapon system, the operator Rating remains in the 70s. The very nature of 300 BLK cartridge combustion is difficult to make quieter on this bolt-action weapon system.  It is hypothesized that adding system mass to both the rifle and the silencer could potentially make the operator risk even lower; as it stands, the system is exceedingly quiet. It is likely that personnel standing shoulder-to-shoulder with the shooter would seldom need hearing protection, for all practical purposes.

PEW Science Research Note 4:  PEW-SOFT HD Version 2.2.8 Alpha contains a revised near field blast propagation engine to model the physics driving the hazard contours displayed in the Hazard Map in this report. The PEW-SOFT HD Blast Hazard Prediction Tool and Hazard Mapper, a research tool continuously under development, is presented in Report 8.1.1.  Note that even with a computational mesh density of 3 inches (relatively coarse for the physical weapon system components analyzed from this test), the map displays appropriate resolution to delineate hazard gradients.

PEW Science Research Note 5: On the topic of limiting signature suppression factors, or “diminishing returns,” it is worthwhile to list the competing products in high performance suppression in this combustion regime that have been examined in the public research pedigree, to date.  The following silencers provide exceptionally high performance subsonic 300 BLK suppression.  Of significant note is the fact that the PTR VENT 1 outperforms all of them in gross signature suppression on this platform and represents one of the greatest performance jumps recently observed.

  • Q Full Nelson (6.99) - an exceptional performer when suppressing subsonic 300 BLK, in a gross sense. This silencer uses conventional baffle technology, large internal expansion volume, and optimized internal porting to excel in this combustion regime. Its construction is such that its shooter’s ear Suppression Rating on this host platform is nominally higher than that of the VENT 1 (for all intents and purposes, the shooter hazard is identical, on average). Its gross suppression performance, however, is eclipsed by that of the VENT 1 and its supersonic (higher pressure) cartridge suppression suffers significantly and is outperformed by many modern silencer designs.  Its muzzle Suppression Rating is 68.5.

  • Liberty Precision Machine Mach-L (6.164) - an extremely high performing rifle silencer across multiple combustion regimes (low pressure, short duration pressure input, as well as high pressure, long duration pressure input). A much more advanced silencer than the Full Nelson, the Mach-L is an example of modern hybrid design proliferation in the market. Note that even with its large size and ancillary flow paths that efficiently relieve pressure stagnation, it still lags behind the PTR VENT 1 in overall suppression performance.  Resonance, FRP control, and other ordinarily less significant performance factors become more important at these levels of performance. Its muzzle Suppression Rating is 71.3.

  • CGS Hyperion (6.71) - another silencer that is significantly more advanced than silencers like the Q Full Nelson, the Hyperion is able to produce advanced signature suppression across an extremely wide range of pressure input, including high pressure magnums. In low pressure regimes, its suppression performance is extremely high. One of the most prolific hybrid designs, the Hyperion technology re-routes blast load input in very early time.  Its flow recombination in later stages is very unique.  However, like the Mach-L, its suppression limits are capped to around the “70 zone” on this weapon system. Its muzzle Suppression Rating is 69.2.

  • Otter Creek Labs Hydrogen-L (6.94) - like the Full Nelson, the Hydrogen-L is an example of “brute force” suppression in that conventional baffle elements are utilized with relatively high volumetric expansion and length. Baffle efficiency with the Hydrogen-L is higher than the Full Nelson through a greater degree of surface area and turbulence generating features that increase the efficiency of gross heat transfer. Some performance deficiencies, again of more significance at these levels of performance, include FRP control and peak momentum accumulation consistency. This silencer exhibits high performance, and is again, systemically outperformed by the VENT 1. Its muzzle Suppression Rating is 65.1.

There are other silencers, in addition to the above, that demonstrate very high performance in pure subsonic 300 BLK suppression. They include those from AAC, Resilient Suppressors, Sig Sauer, CAT, T&K, and others. Some of these silencers are conventional designs, while many are hybrid designs. None of them reach the pure signature suppression performance of the PTR VENT 1 on this platform. The physical mechanisms of signature suppression from the PIP implementation in the VENT 1 are not the same as all of these silencers. The VENT 1 begins the suppression cycle early and its nature allows a more stable flow continuum. Now that both supersonic high pressure and subsonic low pressure inputs have been evaluated and reconciled, this conclusion may be considered largely definitive.

PEW Science Research Note 6: Interestingly, the newly revised AAC 762-SDN-6 (6.221) produces signature components on this weapon system that somewhat grossly mimic the resultant behavior observed from the VENT 1 described in Research Note 1. The new modern 762-SDN-6 isn’t using PIP, but the flow paths through which the early blast propagation flows do seem to lower transient impulsivity and present a smoother continuum than many competing designs. This behavior occurring without the use of PIP may be an indication that this type of behavior could be advanced in other designs and potentially drive further performance advancements in the state of practice.

PEW Science Research Note 7: There are purpose-built subsonic 300 BLK silencers with older technologies that still offer very competitive performance. For example, the Surefire SOCOM300-SPS (6.57) outperforms many silencers in both FRP suppression and overall suppression with subsonic 300 BLK.  Silencer technology is advancing, even as legacy designs continue to offer competitive performance.  Compromises in some performance areas are being tackled; balanced performance is now being achieved in multiple combustion regimes.  This has not always been the case. The reader is encouraged to examine how high flow rate silencers with Flow-Through technology from HUXWRX (OSS) may result in significantly reduced performance with the lower pressure and duration combustion of the subsonic 300 BLK cartridge.  This is showcased in the HUXWRX HX-QD 762 300 BLK test report (6.45).  This type of performance inefficiency is also examined in the Sig Sauer SLH300Ti 300 BLK test report (6.107).  Hybrid technologies from PTR, CAT, Otter Creek Labs, AAC, and others, offer users more versatile silencer solutions.  

The signatures measured at the shooter’s ear are presented and analyzed in the full Member Version of this report. Gross comparisons with other silencers in the subsonic 300 BLK combustion regime are shown below.

6.238.2 Suppression Rating Comparison - Subsonic 300 BLK

The PTR VENT 1 was developed with a focus on high performance sound signature reduction (PEW Science Suppression Rating) in a variety of combustion regimes. As previously discussed, its supersonic and subsonic sound signature suppression performance may be considered extremely high relative to several other systems in the research. Figure 6 shows a performance comparison of many 30 caliber rifle silencer configurations tested with the subsonic 300 BLK cartridge shown in public PEW Science testing, to date. Unsuppressed and suppressed Suppression Ratings are shown for both the shooter and bystanders.  The silencers in the figure are presented in order of total mounted system length, from shortest to longest.

Figure 6. Suppression Rating Comparisons Of .30 Rifle Silencers Using PEW-SOFT 300 BLK Subsonic Test Data

Hazards in Figure 6 are expressed with the Suppression Rating; a holistic parameter that captures human inner ear damage risk potential from a measured impulsive complex overpressure signature during the entire time regime of weapon operation, including combustion, complete blowdown, and all mechanical operation, including the carrier group returning to battery (if applicable), in the true free field. The parameter may be used with the dose chart at the beginning of this report.  The PEW Science Suppression Rating is a damage risk criterion (DRC), a lower Suppression Rating indicates a higher personnel hazard in the free field - it is not a subjective quantity; it is an objective quantification of hearing damage risk potential.  Due to its true free field test data origin and complete waveform analytical calculation basis, it is the only known universal suppressed weapon system signature comparison metric available.

The following gross conclusions can be made from the subsonic 300 BLK bolt-action suppression performance metrics presented in Figure 6, above:

As previously stated in Research Note 5, none of the above silencers reach the pure signature suppression performance of the PTR VENT 1 on this platform. The physical mechanisms of signature suppression from the PIP implementation in the VENT 1 are not the same as all of these silencers. The VENT 1 begins the suppression cycle early and its nature allows a more stable flow continuum. Now that both supersonic high pressure and subsonic low pressure inputs have been evaluated and reconciled, this conclusion may be considered largely definitive. The fact that operator (shooter’s ear) Suppression Ratings from other silencers are close to that of the VENT 1 on this platform is a consequence of limiting physical factors of the host weapon system platform, itself.

PEW Science Research Note 11: The signature of a high performance silencer with subsonic ammunition fired from a bolt-action weapon is significantly suppressed and may not sound like a “gunshot” to the operator or to bystanders.  When such systems enter the 80-zone on the Suppression Rating scale, the signatures have a large proportion of audibly discernable resonance or “metallic” sounding noise.  It is important for operators and bystanders to remain cognizant of the potential hazards of firearm use and the potential lethality of such weapon systems; the operation of such systems, if not in accordance with weapon and silencer manufacturer instructions, may still result in serious injury or death. 

The difference in sound signature suppression performance from silencers in the subsonic 300 BLK suppression regime can be extremely significant. The user is encouraged to be mindful of the degree to which sound signature suppression, and resulting personnel hazards, can vary across designs. Small arm weapon system suppression performance is a spectrum. The PEW Science Suppression Rating and the Silencer Sound Standard help quantify this spectrum for end users and industry, objectively.

6.238.3 Review Summary: PTR VENT 1 on a Q mini FIX 300 BLK with 8-in Barrel

When paired with the Q mini FIX 8-in 300 BLK and fired with Discreet Ballistics 190gr Subsonic Target ammunition, the PTR VENT 1 with its direct-thread mount achieved a composite Suppression Rating™ of 81.5 in PEW Science testing.

The 20-in barrel bolt-action supersonic .308 performance of the PTR VENT 1 with its direct-thread mount system is detailed in Sound Signature Review 6.160, in which it achieved a composite Suppression Rating of 57.3.

As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.

PEW Science Laboratory Staff Opinion:

The PTR VENT 1 is a lightweight and highly advanced 30 caliber rifle silencer that exhibits extremely high sound signature suppression performance.  The combination of performance observations noted in the previous .308 supersonic rifle test report and this subsonic 300 BLK rifle test report demonstrates that the VENT 1 exhibits performance that far exceeds that of typical rifle silencers.  The consistency of the measured signatures is also extremely notable.  This iteration of Purposely Induced Porosity (PIP) technology in the silencer, along with other portions of its design, represent further 3D-printed advancement in the suppressed small arms state of practice.  Now that both supersonic high pressure and subsonic low pressure inputs have been evaluated and reconciled, this conclusion may be considered largely definitive.

As previously presented in the aforementioned high pressure evaluation, the PTR VENT 1 displays highly unusual and advanced signature suppression characteristics. The iteration of PTR Purposely Induced Porosity (PIP) technology in the VENT 1 allows significant and continuous heat transfer and external momentum propagation beginning very early in the first pressure stage response of the silencer all the way through complete blowdown. The resulting measured signatures present with a characteristic “smoothness” and “continuity” devoid of abrupt jet components or transient flow changes observed from several other designs.  Interestingly, this behavior is not limited to full rifle cartridge suppression.  Some early hypotheses and debate regarding the behavior of the PIP technology in the VENT 1 postulated that full high amplitude pressure saturation (an internal propagation of high amplitude blast overpressure through a significant part of the lattice structure) would be required to gain significant suppression efficiency and take adequate advantage of the technology. On the contrary, that initial hypothesis appears to be incorrect. The blast test data measured in this study displays indications that not only does the hybrid design implementation of the PIP technology in the VENT 1 scale its performance into lower combustion pressure and duration regimes, but several of the same behavioral factors remain with its low pressure subsonic 300 BLK suppression that were observed in its high pressure 7.62 NATO suppression.

The overall efficiency and consistency of the VENT 1 design is extremely notable.  To date, there exist no other centerfire rifle silencers in the PEW Science research pedigree demonstrating these types of combined behaviors with this high a performance efficacy.  PEW Science estimates that the performance of the VENT 1 silencer in this combustion regime is one of the most advanced demonstrations of overpressure management observed in the suppressed small arms state of practice. 

The included direct thread mount is easy to install in the VENT 1, and possesses hex-wrench features on the exterior. The mount may be removed and other mounts compatible with the HUB thread pattern may be installed. This feature allows the VENT 1 to be used with a variety of weapon systems.

Although PEW Science has internally evaluated multiple VENT 1 design iterations, no mount varying examination has been performed. The blast chamber vent array in the PTR VENT 1 is expected to be less sensitive to mount variation than some others, with regard to early-time shock reflections producing undue impulse accumulation. Nonetheless, if the user wishes to maintain early flow state for consistent weapon function in the silencer flow rate baseline, it is postulated that minimization of orifice restriction is favorable. Accordingly, shock load reflecting silencer mounting muzzle devices such as the Q Cherry Bomb, and others, may adversely influence early-time flow rate and weapon function.  Mount performance differentials with the PTR VENT 1 are outside the scope of this study.

It is likely, given the venting geometry of the PTR VENT 1, that the silencer is relatively durable on automatic weapons, for a titanium silencer.  PEW Science encourages the end user to contact the manufacturer for barrel length and firing schedule guidance in accordance with their desired use case.

In this review, the PTR VENT 1 performance metrics depend upon suppressing a subsonic intermediate rifle cartridge. While the sound signature of such cartridges can be suppressed to levels that may result in the desire of the shooter and bystanders to not wear hearing protection, PEW Science encourages the reader to remain vigilant with regard to all subsonic rifle cartridge suppression claims. The gas volume and combustion products created by firing a subsonic intermediate rifle cartridge such as 300 BLK are still significant; the measured pressure and impulse magnitudes, and their durations, illustrate this fact.

The hearing damage potential of subsonic rifle use is not insignificant. PEW Science encourages the reader to consider the Suppression Rating when deciding on an appropriate silencer and host weapon combination for their desired use.