SSS.6.160 - PTR VENT 1 and the Savage Model 10 PC .308 (Free Version)
/PTR VENT 1 on a Savage Model 10 .308 with 20-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 PTR Dealers.
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 PTR VENT 1 in this Sound Signature Review is published with the express written permission of PTR Industries Inc.
“In addition to our internal engineering, research, and development, PTR relies upon independent third-party performance validation and analysis expertise from the PEW Science Laboratory. PEW findings contribute significantly to the choices we make throughout each design iteration, resulting in what we believe to be some of the most advanced innovations in the field of suppressor technology.”
This review contains single test results using the PTR VENT 1 with the direct-thread mount on the Savage Model 10 Precision Carbine rifle, chambered in .308WIN with a 20-inch barrel. Federal XM80 149gr ammunition was used in the tests.
Section 6.160.1 contains the PTR VENT 1 test results and analysis.
Section 6.160.2 contains back pressure and Suppression Rating comparisons with selected .30 rifle silencers possessing a PEW Science Back Pressure Metric, Ω [Pa-1] in Omega Zones 6 and above. An updated Ω metric chart for the full suite of publicly evaluated .30 rifle silencers is also provided in this section. Further information about the Ω metric and Omega Zones can be obtained in PEW Science Research Supplement 6.40 (Public Article).
- Section 6.160.3 contains the review summary and PEW Science laboratory staff technical opinions.
Summary: When paired with the Savage M10 20” .308 and fired with Federal XM80, the PTR VENT 1 with the direct-thread mount achieved a Suppression Rating™ of 57.3 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
6.160.1 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
6.160.1.1 SOUND SIGNATURES AT THE MUZZLE
Real sound pressure histories acquired with PEW-SOFT™ are shown below. The waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science testing is 1.0 MS/s (1 MHz). The peaks, shape, and time phasing (when the peaks occur in relation to absolute time and to each other) of these raw waveforms are the most accurate of any firearm silencer testing publicly available. PEW-SOFT data is acquired by PEW Science independent testing; the industry leader in silencer sound research. For more information, please consult the Silencer Sound Standard.
The primary sound signature pressure histories for all 5 shots with the VENT 1 are shown in Figure 1a. The sound signatures of Shot 1 and Shot 2 are shown in Figure 1b, in early time. The real sound impulse (momentum transfer potential) histories from the same 5-shot test are shown in Figure 2a. In Figure 2b, a shorter timescale is shown comparing the impulse of Shot 1 to that of Shot 2 and Shot 3.
Fig 1a. PTR VENT 1 Bolt Action Rifle Muzzle Sound Pressure Signature
Fig 1b. PTR VENT 1 Bolt Action Rifle Muzzle Sound Pressure Signature, Short Time Window
Figure 2a. PTR VENT 1 Bolt Action Rifle Muzzle Sound Impulse Signature
Figure 2b. PTR VENT 1 Bolt Action Rifle Muzzle Sound Impulse Signature, Short Time Window
The above presented test data displays highly unusual and advanced characteristics for the tested combustion regime. The PTR VENT 1 produces free field signature characteristics that illustrate behaviors indicative of both hybrid design technology, as well as ultra-high performance suppression. In examining the measured signatures in both pressure space (Figure 1) and impulse space (Figure 2), the following progressive observations are made:
Typical coupled muzzle blast jetting and bullet shock present in the expected amplitude range with notable precursor internal combustion consistency (30 ms, Fig. 1b).
Somewhat atypical minimization of first-round-pop (FRP) overpressure is noted followed by a highly atypical reduction in overpressure propagation from all shots, without substantial decoupling post-negative phase (30.2 ms and later, Fig. 1b).
Strong consistency throughout initial pressure propagation, resulting in impulse accumulation that initiates the primary phase at higher amplitude due to the phenomena in (2), with noted rate decrease prior to maxima (32 ms, Fig. 2b).
Highly atypical blowdown rate (Fig. 1a) in the context of (2) and (3). Free field overpressure amplitude is shown to continuously propagate, without an initial decoupling from the exit event, and to still exhibit a favorable decay trend to ambient.
The PTR VENT 1 exhibits the consistency of an ultra-high performance precision rifle silencer with the early-time flow rate of a hybrid design, while demonstrating external distal momentum accumulation characteristics that may lead the analyst to initially assume a more severe signature. On the contrary, the absence of both significant rarefaction and the phenomena in (2) create a less impulsive transition from initial jet to primary accumulation. Along with its significantly faster blowdown and efficient pressure throttling, these characteristics produce a signature that is one of the most unique examined in the research pedigree, to date.
PEW Science Research Note 1: This iteration of the PTR Purposely Induced Porosity (PIP) technology is highly advanced and tuned for the tested combustion regime. The VENT 1, like the smaller 5.56mm VENT 3 (6.135) and 9mm VENT 2 (6.131), possess elements of both conventional silencer geometry, as well as high flow rate characteristics in certain portions of the combustion propagation cycle. The PIP technology in the VENT 1 exhibits the blast momentum consistency characteristics of the SNIPER2 hybrid technology in the CAT JL (6.147) but with a pressure amplitude throttle that is more significant. As tested, the PTR VENT 1 is 0.6 inches longer than the CAT JL, and this extra length is partially responsible for performance gains. However, it is important to note that regardless of this length increase, there are phenomena present in the VENT 1 signatures that illustrate similar peak momentum accumulation (Omega Metric) with more expedient blowdown. The blast venting structure, along with the PIP technology in the VENT 1, is observed to throttle overpressure with a smoother transition between each primary phase of flow. PEW Science postulates that this behavior is made possible directly by the porosity in portions of the silencer. Blast load is purposely “leaked” forward through every phase of combustion propagation longitudinally, and with each transition, heat transfer efficiency is further maximized. FRP is effectively nullified.
PEW Science Research Note 2: To elaborate on the above performance demonstrations, it is important to note the method by which high pressure stagnation relief is achieved with the particular implementation of the PIP technology in the VENT 1. When traditional high performance supersonic silencers relieve stagnation through the combustion propagation cycle, they often make use of legacy Omega baffle derivative technology; coaxial elements providing alternate flow paths away from primary jetting. This highly efficient behavior pays significant performance dividends and may be accomplished through a variety of methods and geometries. In the research pedigree to date, there are several examples of this technology and its derivatives proving to be highly effective, including those by CGS, Dead Air, CAT, Liberty Precision Machine, SilencerCo, Otter Creek Labs, and others. However, one inherent limitation of such technologies is the need to create additional volumetric expansion and contraction throughout the stagnation relief zones and do so throughout the entire propagation cycle. This limitation results in the need for increasing complexity in flow paths; not unattainable, but also eventually potentially cumbersome to manage without additional length to accommodate the time regime above critical pressure. It appears as though PIP technology may offer another option to increase efficiency in relieving stagnation. PEW Science postulates that when implemented as done in the VENT 1, it is combined with simple baffle geometry to provide simultaneous stagnation relief and direct heat transfer. The very act of pressurizing the interstitial space between PIP regions activates their purpose - the structure’s nature lends itself to creating an immediate flow gradient that can be tuned for each pressure region depending upon the expected critical pressure amplitude. If this postulation is correct, the implication is that the typical paradigm for this type of silencer design has now been shifted. PEW Science concludes with a high degree of confidence that this is the case. The combination of post-exit low amplitude jetting, nested precursor, and shorter blowdown duration, alone, strongly supports this hypothesis.
PEW Science Research Note 3: 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 PTR VENT 1 is 9.1 inches long in the tested configuration. Regardless of length, the performance differential between it and its nearest neighbors is significant. The muzzle Suppression Rating of the VENT 1 is over 49. This is unprecedented in PEW Science testing, on this host weapon. The shooter’s ear Suppression Rating of the VENT 1 is 56. This is, again, unprecedented. The entire pressure field exhibits abnormally low intensity.
For end-user context, the CGS Hyperion (6.27), as tested, is 9.5 inches long. Its muzzle Suppression Rating is 41.7; a significant differential. The Dead Air Nomad-L (6.55) has a nominally higher muzzle Suppression Rating than the Hyperion at 41.9, and is 8.5 inches long. There are no closer performers in pure muzzle pressure field suppression in the pedigree. At the shooter’s ear, the closest competitors in Suppression Rating are the aforementioned CAT JL, producing 53.5 and the Diligent Defense Enticer-L (6.67) producing 51.8. Though not as significant as the muzzle Suppression Rating differentials, the shooter’s ear risk reduction differences are non-trivial, given the context of the research pedigree examination, to date.
PEW Science Research Note 4: Blast momentum transfer potential (impulse) onset transitions, phase timing, and pressure blowdown durations, all significantly contribute to the severity of suppressed small arm weapon system signatures. When comparing the free field signature propagation from the PTR VENT 1 to that of the propagation from other silencers on this host weapon, the greatest differentials are:
The VENT 1 signature immediately drops to low amplitude, but without significant negative phase transition. This is due to the PIP enabling continuous precursor flow propagation. Transitions are “smoothed” (see Research Note 1).
The VENT 1 signature normalizes expediently and stagnation does not relieve at high frequency; there are no rapid depressurization cycles throughout primary blowdown (see Research Note 2).
Without the significant decoupling in (1), and without the abrupt flow rate changes in (2), the PIP technology is free to maximize heat transfer with minimal consequences to flow through the primary bore. There appear to be no phases of flow in which adverse turbulent jetting would disrupt consistency. PEW Science postulates that in addition to superior pressure field severity reduction, these technical factors may result in a silencer that exhibits a low degree of disruption to projectile flight precision. Internal PTR (manufacturer) testing demonstrates a high degree of projectile precision with this silencer technology, which stands to reason given the above observations. More third-party research is needed for further PEW Science conclusions and commentary. As an aside, anecdotal reports indicate a correlation between these types of momentum propagation consistency with the test apparatus and system precision.
PEW Science Research Note 5: 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.
As typically indicated, first-round sound signatures always differ from subsequent shots, as the atmosphere within the silencer changes. The FRP phenomenon cannot always be shown by viewing only the peak sound pressure. This is one of the reasons why The Silencer Sound Standard requires examining multiple sound signature metrics. Ammunition consistency can play a role in the determination of FRP, however, the close examination of measured pressure and impulse waveforms typically excludes ammunition from the possible factors influencing true FRP, due to the relative consistency of most high quality factory ammunition.
PEW Science has made a concerted effort to characterize the FRP phenomenon with true physiological human inner-ear response analyses. Additional PEW Science Member Research Supplements containing this information are released periodically. The full Member Version of this review contains complete analysis, including high fidelity signature information measured near the shooter’s head.
6.160.2 Relative Suppression Rating and Back Pressure Comparisons (.30 Rifle Silencers)
The PTR VENT 1 suppressor is intended to offer significant sound signature suppression across the pressure field, with lower back pressure than typical designs. PEW Science has developed an empirical relation to quantify the back pressure (flow restriction) of silencers. Figure 5 and Figure 6 show supersonic suppression and back pressure comparisons between selected 7.62mm (30 caliber) rifle silencers shown in public PEW Science Sound Signature Reviews, as of the date of this review publication. The results shown in Figure 5 and Figure 6 are calculated from real test data acquired with PEW-SOFT. Please note the following:
The PEW Science Back Pressure Metric, Ω [Pa-1], may be generated for any silencer and suppressed weapon system using any suitable raw external overpressure signature data acquired 1.0 m left of the silencer end cap. PEW Science highly recommends data acquisition in accordance with The Silencer Sound Standard.
Omega Zones are presented in Table 2, below, which are intended to provide guidance to weapons developers, silencer designers, and end-users, with regard to flow restriction characteristics of different silencer designs. It is very important to note that silencers possessing a relatively high Ω can still provide functional use on weapon systems. Some weapon systems are more sensitive to Ω than others.
It is important to note that a silencer’s Omega Zone can shift when using a mounting scheme that differs from that used in the testing referenced in the published PEW Science Sound Signature Reviews. This phenomenon occurs due to some silencer mounting schemes significantly influencing flow restriction with some silencer designs.
The theoretical lower limit of flow restriction, or so-called "zero back pressure" would be represented by the unsupressed state, Ω = 0 [Pa-1].
PEW Science acknowledges that other dynamic events occur within a suppressed weapon system that can also influence weapon function. Therefore, PEW Science acknowledges that Ω is not the sole parameter one must consider for total supppressed weapon system operation. However, PEW Science postulates that the Ω metric influence can be significant. Note that weapon system influence is also a function of early-time wave propagation factors which may be measured inside the system, in close proximity to the muzzle orifice. These factors include the so-called PEW Science Alpha parameter; a subject of internal research.
The Back Pressure Metric relations are most easily viewed on a logarithmic scale (See Figure 6).
Figure 5. Omega Back Pressure Metric And Suppression Rating Comparisons Of .308 Rifle Silencers Using PEW-SOFT Data and Analysis
As stated above, the PEW Science Back Pressure Metric is most easily viewed on a logarithmic scale. The metric is nonlinear; the shape of the trend in the data presented in Figure 6, below, illustrates the potential thresholds of extreme flow rate (approaching the unsuppressed state) and extreme flow restriction (approaching the trapping of the maximum amount of combustion byproducts in a system).
Figure 6. Omega Back Pressure Metric Comparisons Of .308 Rifle Silencers Using PEW-SOFT Data and Analysis
Omega characterizes silencer back pressure. It is important to note that back pressure is not blow back. The back pressure of a silencer is the flow restriction it introduces in a suppressed weapon system. The blow back phenomenon that can occur during the use of a suppressed weapon system is caused by the reciprocating system actuating too early relative to overpressure decay within the weapon system, resulting in exposure of excessive internal system overpressure to atmosphere. Some weapons may be tuned to function well with silencers in a high Omega Zone. Some weapons may require low-Omega silencers due to constraints in their operating system(s). Omega metric technical details can be found in PEW Science Public Research Supplement 6.40.
Table 2. PEW Science Back Pressure Metric Omega Zones And Suppressed Weapon System Functional Descriptions
As stated above, weapon system influence is a function of both Ω and early-time wave propagation factors which may be measured inside the system, in close proximity to the muzzle orifice. These factors include the so-called PEW Science Alpha parameter; a subject of internal research. The PTR VENT 1 possesses blast chamber venting and multiple porosity zones through multiple stages which most likely significantly influence both early time shock reflections near the muzzle and late time momentum accumulation. The PIP technology in the PTR VENT 1 results in an unusually low Omega Metric for the degree of measured sound field suppression. As previously discussed in Research Note 1, the blowdown being as expedient as measured in the testing is relatively unusual; the overall sound field hazard profile from the PTR VENT 1 is also unusually lower risk, as well.
The suppression performance of the PTR VENT 1 on this platform, holistically, is best compared with the aforementioned CAT JL (6.147), CGS Hyperion (6.27), Dead Air Nomad-L (6.55), and Diligent Defense Enticer-L (6.67), as well as with the Otter Creek Labs Hydrogen-L (6.81) and Resilient Suppressors Jolene (6.137). It should be noted that all of the aforementioned silencers exhibit extremely high suppression performance in this combustion regime. These silencers objectively outclass most 30 caliber rifle silencers evaluated on this host weapon system by PEW Science, to date. The PTR VENT 1 outperforms all of these silencers and does so with a design envelope and consistency that form an unprecedented combination of performance. As previously described in context in Research Note 2, the VENT 1 is 9.1 inches long as tested, but regardless of this length, the performance differential between it and its nearest neighbors is significant.
PEW Science urges the reader not to misconstrue a low Omega metric with the mirroring of unsuppressed weapon function, nor a high Omega Metric with absolute use prohibition on semi-automatic systems. Each weapon system may experience varying sensitivity to different Omega Zones and users may exhibit varying preference for weapon system function and operability. The Zones are provided by PEW Science to assist the reader with determination of postulated applicability of silencer types, as some users may only have experience with certain silencers. The Omega Metric is one performance indicator; it allows overall flow rate phenomena to be categorized independently from sound signature suppression performance. Note that weapon system influence is also a function of early-time wave propagation factors which may be measured inside the system, in close proximity to the muzzle orifice.
PEW Science Research Note 8: The PIP technology in the 5.56mm VENT 3 and 9mm VENT 2 are more purposely-adapted to high gross flow rate than in the VENT 1. Nonetheless, it is still postulated that the performance of the VENT 1 on semiautomatic host weapon platforms exhibits a relatively high degree of shooter hazard reduction. The early-time flow rate in the VENT 1 is high and the blowdown expedient. Further testing and analysis is needed to quantify its performance on reciprocating systems.
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.
6.160.3 Review Summary: PTR VENT 1 on a Savage Model 10 .308 with 20-in Barrel
When paired with the Savage M10 20” .308 and fired with Federal XM80, the PTR VENT 1 with the direct-thread mount achieved a Suppression Rating™ of 57.3 in PEW Science testing.
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 this test report demonstrate 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.
This iteration of the PTR PIP technology is highly advanced and tuned for the tested combustion regime. The VENT 1, like the smaller 5.56mm VENT 3 and 9mm VENT 2 , possess elements of both conventional silencer geometry, as well as high flow rate characteristics in certain portions of the combustion propagation cycle. The PIP technology in the VENT 1 exhibits the blast momentum consistency characteristics of the SNIPER2 hybrid technology in the CAT JL but with a pressure amplitude throttle that is more significant. As tested, the PTR VENT 1 is 0.6 inches longer than the CAT JL, and this extra length is partially responsible for performance gains. However, it is important to note that regardless of this length increase, there are phenomena present in the VENT 1 signatures that illustrate similar peak momentum accumulation with more expedient blowdown. This demonstrates a holistic technological performance shift.
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.
PEW Science postulates that in addition to superior pressure field severity reduction, the presented technical factors may result in a silencer that exhibits a low degree of disruption to projectile flight precision. Internal PTR testing demonstrates a high degree of projectile precision with this silencer technology, which stands to reason given the above observations. More third-party research is needed for further PEW Science conclusions and commentary. As an aside, anecdotal reports indicate a correlation between these types of momentum propagation consistency with the test apparatus and system precision. Flash suppression performance is also expected to be relatively high. Again, further research is needed.
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 so-called HUB threading system 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.
The suppression performance of the PTR VENT 1 on this platform, holistically, is best compared with the aforementioned CAT JL, CGS Hyperion, Dead Air Nomad-L, and Diligent Defense Enticer-L, as well as with the Otter Creek Labs Hydrogen-L and Resilient Suppressors Jolene. It should be noted that all of the aforementioned silencers exhibit extremely high suppression performance in this combustion regime. These silencers objectively outclass most 30 caliber rifle silencers evaluated on this host weapon system by PEW Science, to date. The PTR VENT 1 outperforms all of these silencers and does so with a design envelope and consistency that form an unprecedented combination of performance. As previously noted, the VENT 1 is 9.1 inches long as tested, but regardless of this length, the performance differential between it and its nearest neighbors is significant.
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 supersonic centerfire rifle cartridge; no easy task. PEW Science encourages the reader to remain vigilant with regard to all supersonic centerfire rifle suppression claims. The gas volume and combustion products created by the firing of the supersonic .308WIN cartridge are significant; the measured pressure and impulse magnitudes, and their durations, illustrate this fact.
The hearing damage potential of supersonic centerfire rifle use is significant. PEW Science encourages the reader to consider the Suppression Rating when deciding on an appropriate silencer and host weapon combination for their desired use.
