SSS.6.178 - Otter Creek Labs Infinity and the Savage Model 10 PC .308 (Free Version)
/Otter Creek Labs Infinity on a Savage Model 10 .308 with 20-in Barrel
The Infinity is a 30 caliber centerfire rifle silencer designed by Otter Creek Labs. The Infinity is intended to suppress many cartridges with projectiles appropriately sized to travel through the bore, and may be used with severe firing schedules. It has a 1.73-inch diameter and is 6.6 inches long without a mount. The silencer does not include any mounts; the proximal end of the Infinity is threaded 1.375-24 tpi to accommodate “HUB” compatible mounting systems. The silencer body is 3D printed from Inconel 718 alloy and the retail package includes multiple heat-treated stainless steel end caps that change system behavior. The user may choose to install different end caps to achieve varying flow states appropriate for the combustion dynamics of the chosen cartridge and weapon system. With an end cap installed, the silencer weighs 20 ounces and with a Rearden titanium direct-thread mount, weighs 20.8 ounces and is 6.8 inches long, as tested. The Otter Creek Labs Infinity can be obtained from Silencer Shop.
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-OCL-103-001-24. Therefore, data pertaining to the Infinity in this Sound Signature Review is published with the express written permission of Otter Creek Labs, LLC.
This report contains two sets of testing and analytical results using the Otter Creek Labs Infinity with solid and vented 7.62 mm end caps 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 6.178.1 contains an overall Otter Creek Labs 30 caliber rifle silencer bolt-action rifle performance summary.
Section 6.178.2 contains the Infinity 7.62 mm solid end cap test results and analysis.
Section 6.178.3 contains the Infinity 7.62 mm vented end cap test results and analysis.
Section 6.178.4 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 5 and below. 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 6.178.5 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 with the solid 7.62 end cap, the Otter Creek Labs Infinity achieved a Suppression Rating™ of 39.0 in PEW Science testing. With the vented 7.62 end cap, the Otter Creek Labs Infinity achieved a Suppression Rating of 31.8.
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
6.178.1 Otter Creek Labs 30 Caliber Silencer Bolt-Action Performance Summary
The PEW Science Silencer Sound Standard public research pedigree includes the evaluation of five 30 caliber rifle silencers designed and manufactured by Otter Creek Labs. Comprehensive performance Rankings are tabulated in Section 7 of the Standard. The scope of this report contains 7.62x51mm NATO combustion suppression analysis. To that end, Figure 1 presents a performance comparison of six Otter Creek Labs 30 caliber rifle silencer configurations currently evaluated. The configurations include:
6.178 - Infinity (7.62 mm vented end cap): a hybrid design silencer with ancillary axial and annular venting at the distal end.
6.142 - Polonium-30: a conventional cone design silencer (compact-size).
6.178 - Infinity (7.62 mm solid end cap): a hybrid design silencer with only axial bore venting at the distal end.
6.49 - PR30S: a curved cone Omega-baffle derivative silencer (mid-size, discontinued).
6.48 - PR30L: a curved cone Omega-baffle derivative silencer (full-size, discontinued).
6.81 - Hydrogen-L: a conventional cone design silencer (full-size).
The silencers are presented in order, in accordance with their distal blast momentum propagation rate, from least restrictive to most restrictive. The rate of distal external blast momentum accumulation is quantified by the calculated PEW Science Omega Metric (6.40).
Figure 1. Suppression Rating Comparisons of Otter Creek Labs Rifle Silencers Using PEW-SOFT 7.62×51mm Supersonic Test Data and PEW Science Analysis
From the above bolt-action rifle performance metrics, it can be concluded that signature suppression levels may increase or decrease in accordance with not only distal blast momentum propagation rate, but also in accordance with other signature components that vary based on silencer internal design. Furthermore, it is extremely important to note that the early-time flow rate of a silencer may also influence performance, independent of late-time distal momentum control. For example, the Polonium-30 (6.142) may have a lower rate of distal blast momentum propagation (lower Omega Metric) than the Infinity with its solid 7.62 end cap, but the Infinity most certainly has a higher early-time flow rate than the Polonium-30. This may result in varying levels of semiautomatic weapon platform performance comparison. For further details on such performance factors, the reader is encouraged to examine the semiautomatic performance evaluation of the Otter Creek Labs Infinity with multiple end caps in the 5.56x45mm NATO combustion regime in the follow-on MK18 testing and analysis report from this Infinity research program (6.179). MK18 performance comparisons with the Polonium-30 (6.143), Polonium (6.75), and Polonium-K (6.95) are also included in that report.
The 7.62x51mm NATO bolt-action evaluation of the Otter Creek Labs Infinity with both 7.62 solid and 7.62 vented end caps follows.
6.178.2 Otter Creek Labs Infinity 7.62 Solid End Cap Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Otter Creek Labs Infinity with 7.62 solid cap 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. Otter Creek Labs Infinity Solid End Cap Sound Metric Summary
6.178.2.1 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 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 with the Infinity are shown in Figure 2a. The sound signatures of Shot 1, Shot 2, and Shot 3 are shown in Figure 2b, in early time. The real sound impulse (momentum transfer potential) histories from the same 5-shot test are shown in Figure 3a. In Figure 3b, a shorter timescale is shown comparing the impulse of Shot 1 to that of Shot 2 and Shot 3.
Fig 2a. Otter Creek Labs Infinity Solid End Cap Bolt Action Rifle Muzzle Sound Pressure Signature
Fig 2b. Otter Creek Labs Infinity Solid End Cap Bolt Action Rifle Muzzle Sound Pressure Signature, Short Time Window
Figure 3a. Otter Creek Labs Infinity Solid End Cap Bolt Action Rifle Muzzle Sound Impulse Signature
Figure 3b. Otter Creek Labs Infinity Solid End Cap Bolt Action Rifle Muzzle Sound Impulse Signature, Short Time Window
As discussed in the preceding performance summary, the Otter Creek Labs Infinity is a 30 caliber rifle silencer that is classified as a hybrid design in the PEW Science research taxonomy. More specifically, the Infinity is classified as a staged hybrid. Hybrid design silencers are those in which elements of both conventional and high flow rate silencers are used, coupled with other technology variations and staged elements to provide parametrically varied performance attributes. Such attributes include the ability to reduce early-time shock reflections while significantly altering the rate of proximal and distal venting. These silencers may allow for minimal reciprocating weapon functional influence, while at the same time significantly suppressing signature to the operator and bystanders. Hybrid designs span a large range of the market in both brand and performance in different combustion regimes. There also exist subcategories of this class of silencers that have been shown to demonstrate efficacy in multiple flow regimes. Discussion of these subcategories is outside the scope of this report. Other hybrid designs and staged hybrids include those from PTR, CAT, CGS, SilencerCo, Surefire, and others. For an overview of the three primary classes of rifle silencer designs, the reader is encouraged to review PEW Science Research Supplement 6.169.
The Infinity hybrid design is characterized by the following physical design attributes:
Early venting in the first expansion (blast) chamber prevents excessive blast load impulse accumulation in early time.
Clearing off of the first reflector (blast baffle) occurs through venting on both the convex surface and boundary walls.
Multiple stages are utilized; high pressure baffle geometry in the first stage, lower pressure geometry in the second stage, and varied alternate flow path geometries that are utilized differently in accordance with user choice of end cap.
PEW Science Research Note 1: When fitted with the solid 7.62 end cap, the Otter Creek Labs Infinity functions as a 30 caliber rifle silencer with a relatively high early-time flow rate and a moderate to restricted late-time flow rate. This performance is demonstrated by the following characteristics shown in the above test data:
Relatively longer blowdown duration (Fig. 2a).
Lack of decoupled ground reflection, consistent with (1).
Relatively short initial positive phase blast load duration with coincident rarefaction (Fig. 2b).
Blast pressures reach maxima later in time, post-initial jetting (Fig. 2b).
Relatively typical duration rise to maximum positive phase blast impulse for the silencer’s size (Fig. 3a).
The reader is encouraged to compare and contrast the behavior of the HUXWRX FLOW 762 Ti (6.113) and the Otter Creek Labs Infinity with 7.62 solid end cap, described above. The differences in gross behavior provide an excellent example of Flow-Through vs. hybrid design performance.
PEW Science Research Note 2: The taxonomic classification of silencer technology is not solely academic. On the contrary, it is important for users to be aware of how the performance of such technologies manifests in practical use. Hybrid silencer designs are not “Flow-Through” designs. That technology is only available from HUXWRX, and its principles of operation differ significantly from all hybrid designs. Although some hybrid design silencers may be marketed as “Flow-Through” silencers by manufacturers, dealers, and distributors that sell products, the physical mechanisms and performance differentials between all of the technologies are significant.
The reader is highly encouraged to examine the in-depth laboratory testing and analysis of HUXWRX systems for a detailed description of pertinent behavioral factors. For example, when distal gas velocity increases significantly, as it does in a true Flow-Through design, there are consequences to the sound field that may induce unfavorable frequency components and reflection phenomena. For example, when fired outside of the free field, near reflecting surfaces, Flow-Through silencers may induce significant blast load reflections. The amplifying reflection factor, c_r, is directly proportional to both amplitude and angle of incidence; resultant reflected blast overpressures are often over twice as high as measured free field values. PEW Science postulates this performance differential will be apparent to users operating near berms, vehicles, awnings, structure walls, and other reflecting surfaces. Anecdotal user reports have indicated flat obstacles in the near field sized approximately 4-ft cubed (standard IBC chemical totes) present enough reflecting surface area for significantly noticeable signature severity increase with HUXWRX Flow-Through silencers. These reports are congruent with characterized blast propagation behavior in laboratory testing. Various hybrid silencer designs mitigate these adverse signature effects, including technologies from PTR (Purposely Induced Porosity, or “PIP”) and CAT (Surge Bypass, SNIPER2, SB-SHOCK). It is expected that the hybrid design Otter Creek Labs Infinity also mitigates these effects, particularly with its solid end cap installed.
PEW Science Research Note 3: The Otter Creek Labs Infinity produces a relatively significant first-round-pop (FRP) intensity to bystanders on the tested weapon system. However, the relative intensity of FRP from the Infinity may vary based upon the shot string; some later shots may produce signatures on-par with FRP severity. More research is needed; it is postulated that some cavity volumes are evacuated differently during blowdown, depending on end cap use.
Hybrid technologies are not necessarily always superior to Flow-Through designs. One benefit of true Flow-Through technology over the specific hybrid technology implemented in the Otter Creek Labs Infinity is the use of longer flow paths. This allows the HUXWRX FLOW 762 Ti to accomplishing similar free field suppression performance over a shorter length envelope. Different silencer technologies exhibit performance tradeoffs.
PEW Science Research Note 4: The gross suppression performance of the Infinity with solid 7.62 end cap is higher than that of the Otter Creek Labs Polonium-30 (6.142), SilencerCo Omega 300 (6.10), SilencerCo Harvester 300 (6.31), Dead Air Nomad-30 1st Gen (6.43), Dead Air Sandman-S (6.11), Rugged Radiant (6.12), Q Trash Panda (6.4), and others. The reader is encouraged to examine the bar chart in Figure 10 of this article, along with the comprehensive and sortable Rankings Table in Section 7 of the Standard.
Close to the weight of 20 ounces, the Infinity outperforms the Dead Air Sandman-L (6.23) and Surefire SOCOM762-RC2 (6.26). The Suppression Rating Parametric Visualization Tool in the Members Ranking Section may be used to filter for weight, length, and other parameters.
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.
Test data and analysis of the signatures measured at the shooter’s ear are presented in the full Member Version of this report.
The vented end cap evaluation follows.
6.178.3 Otter Creek Labs Infinity Vented End Cap Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Otter Creek Labs Infinity with 7.62 vented end cap is shown in Table 2. The data acquired 1.0 m (39.4 in) left of the muzzle is available for viewing to all. Again, 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 2. Otter Creek Labs Infinity Vented End Cap Sound Metric Summary
6.178.3.1 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 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 with the Infinity with 7.62 vented end cap are shown in Figure 6a. The sound signatures of Shot 1, Shot 2, and Shot 3 are shown in Figure 6b, in early time. The real sound impulse (momentum transfer potential) histories from the same 5-shot test are shown in Figure 7a. In Figure 7b, a shorter timescale is shown comparing the impulse of Shot 1 to that of Shot 2, Shot 3, and Shot 5.
Fig 6a. Otter Creek Labs Infinity Vented End Cap Bolt Action Rifle Muzzle Sound Pressure Signature
Fig 6b. Otter Creek Labs Infinity Vented End Cap Bolt Action Rifle Muzzle Sound Pressure Signature, Short Time Window
Fig 7a. Otter Creek Labs Infinity Vented End Cap Bolt Action Rifle Muzzle Sound Impulse Signature
Fig 7b. Otter Creek Labs Infinity Vented End Cap Bolt Action Rifle Muzzle Sound Impulse Signature, Short Time Window
When fitted with the vented 7.62 end cap, the performance of the Otter Creek Labs Infinity changes significantly. The varying stages of the silencer are utilized differently, and blast loads are now vented from both annular space and additional primary axial volume. This results in the following behavioral changes, observed in the above data plots:
More expedient blowdown, with ground reflection beginning to decouple (Fig. 6a).
More expedient initial jetting with prolonged initial positive phase, signifying greater early momentum propagation (Fig. 6b).
Faster rise to maximum positive phase blast load impulse (lower Omega Metric) in all shots (Fig. 7a).
Uncontrolled erratic blast load momentum propagation in some shots, post-FRP (see Shot 5, Fig. 7).
Observation (4), above, is relatively common when excess blast load vent area is introduced into a primary flow path. It is likely that this adverse erratic combustion propagation originates from the ancillary venting of the primary bore,
PEW Science Research Note 7: The silencer has now changed function; the Infinity with a vented end cap is no longer a low-alpha, moderate-omega hybrid- it has been transformed into a low-alpha, low-omega hybrid. While many positive attributes of its hybrid design are maintained, higher gas particle velocity and momentum propagation begin to push its performance envelope into a regime in which both bystander and operator risk may be compromised on this weapon platform. Overall pressure field shape is also changed due to particle velocity gradients. For example, note that the muzzle (bystander) Suppression Rating is extremely similar. However, the shooter’s ear (operator) Suppression Rating drops a full category.
It should be noted that despite this performance drop, the vented 7.62 end cap configuration of the Otter Creek Labs Infinity outperforms the vented configuration of the CGS Helios QD (6.13), the Surefire SOCOM762-MINI2 (6.106), the Energetic Armament VOX-S (6.3), and the Rugged Razor762 (6.16) on this host weapon system.
Signature analysis of test data acquired near the operator’s head is presented in the full report.
Comprehensive performance comparisons follow.
6.178.4 Relative Suppression Rating and Back Pressure Comparisons (.30 Rifle Silencers)
The Otter Creek Labs Infinity suppressor is intended to offer reduced back pressure when compared to some other designs, regardless of end cap choice. With a vented end cap, the Infinity may significantly reduce back pressure, with blast propagation severity penalty. PEW Science has developed an empirical relation to quantify the back pressure (flow restriction) of silencers. Figure 10 and Figure 11 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 10 and Figure 11 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 3, 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 PEW Science Alpha parameter; a subject of internal research.
The Back Pressure Metric relations are most easily viewed on a logarithmic scale (See Figure 11).
Figure 10. 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 11. 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 3. 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 PEW Science Alpha parameter; a subject of internal research. The Otter Creek Labs Infinity possesses blast chamber venting that influences both early time shock reflections near the muzzle and late time momentum accumulation. Due to the overall design of the Infinity, its Omega Metric is relatively low for its suppression performance.
The gross suppression performance of the Infinity with solid 7.62 end cap is higher than that of the Otter Creek Labs Polonium-30 (6.142), SilencerCo Omega 300 (6.10), SilencerCo Harvester 300 (6.31), Dead Air Nomad-30 1st Gen (6.43), Dead Air Sandman-S (6.11), Rugged Radiant (6.12), Q Trash Panda (6.4), and others. The reader is encouraged to examine the comprehensive and sortable Rankings Table in Section 7 of the Standard.
The performance of the Infinity with its solid end cap is very similar to that of the HUXWRX FLOW 762 Ti (6.113) on this weapon system. However, The FLOW 762 Ti may provide a more favorable operator experience on some reciprocating weapons. System parameters and operating environment play a significant role in this performance comparison.
With its vented end cap, many positive attributes of the Infinity’s hybrid design are maintained, but higher gas particle velocity and momentum propagation begin to push its performance envelope into a regime in which both bystander and operator risk may be compromised on this weapon platform. Overall pressure field shape is also changed due to particle velocity gradients. For example, note that the muzzle (bystander) Suppression Rating is extremely similar. However, the shooter’s ear (operator) Suppression Rating drops a full category.
PEW Science Research Note 9: Hybrid technologies continue to proliferate in the market; designs like the Surefire SOCOM556-RC3 (6.151), SilencerCo Velos (6.134), CAT WB (6.129), FOR Systems Monarch 7.62 (6.155), and others, are joined by silencers like the Otter Creek Labs Infinity to balance suppression performance in multiple environments with higher flow rates to mitigate operator hazards.
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 10: The Otter Creek Labs Infinity retail package ships without a mount. While this lowers cost and gives the user maximum flexibility, it also requires the user to remain diligent and be responsible for their mounting system choice. Appropriate mount for both practical field use case and blast load dynamics is paramount; the Infinity has a significant degree of early-time venting. This beneficial performance trait may be compromised through the use of mounts that induce undue blast load reflection, such as compensators like the "Cherry Bomb” and others. Use of such devices may increase the effective back pressure of a system by elevating the Alpha parameter; the early-time blast load impulse accumulation inside the first expansion chamber of the silencer. PEW Science encourages the user to contact the silencer manufacturer for a recommended mounting system for their requisite application(s).
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.
6.178.5 Review Summary: Otter Creek Labs Infinity on a Savage Model 10 .308 with 20-in Barrel
When paired with the Savage M10 20” .308 and fired with Federal XM80 with the solid 7.62 end cap, the Otter Creek Labs Infinity achieved a Suppression Rating™ of 39.0 in PEW Science testing. With the vented 7.62 end cap, the Otter Creek Labs Infinity achieved a Suppression Rating of 31.8.
As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.
PEW Science Laboratory Staff Opinion:
The Otter Creek Labs Infinity is a severe-use mid-size 30 caliber rifle silencer with an advanced but flexible hybrid design. The silencer is user-configurable for different blast load flow states and allows the operator to adapt the system to a variety of host weapons. With a high early-time flow rate, the silencer may perform well on semiautomatic platforms even in its most restrictive configuration. For sensitive platforms, the user may fully vent blast loads from multiple stages of the silencer, lowering back pressure to a minimum for this design. The Infinity is 3D-printed from Inconel alloy and is expected to offer significant durability for hard use.
The Otter Creek Labs Infinity is a 30 caliber rifle silencer that is classified as a hybrid design in the PEW Science research taxonomy. More specifically, the Infinity is classified as a staged hybrid. Hybrid design silencers are those in which elements of both conventional and high flow rate silencers are used, coupled with other technology variations and staged elements to provide parametrically varied performance attributes. Such attributes include the ability to reduce early-time shock reflections while significantly altering the rate of proximal and distal venting. These silencers may allow for minimal reciprocating weapon functional influence, while at the same time significantly suppressing signature to the operator and bystanders. Hybrid designs span a large range of the market in both brand and performance in different combustion regimes.
The Otter Creek Labs Infinity produces a relatively significant first-round-pop (FRP) intensity to bystanders on the tested weapon system. However, the relative intensity of FRP from the Infinity may vary based upon the shot string; some later shots may produce signatures on-par with FRP severity. More research is needed; it is postulated that some cavity volumes are evacuated differently during blowdown, depending on end cap use. The gross suppression performance of the Infinity with solid 7.62 end cap is higher than that of the Otter Creek Labs Polonium-30, SilencerCo Omega 300, SilencerCo Harvester 300, Dead Air Nomad-30 1st Gen, Dead Air Sandman-S, Rugged Radiant, Q Trash Panda, and others. The reader is encouraged to examine the comprehensive and sortable Rankings Table in Section 7 of the Standard. Close to the weight of 20 ounces, the Infinity also outperforms similarly weighted silencers such as the Dead Air Sandman-L and Surefire SOCOM762-RC2.
When fitted with the vented 7.62 end cap, the performance of the Otter Creek Labs Infinity changes significantly. The varying stages of the silencer are utilized differently, and blast loads are now vented from both annular space and additional primary axial volume. While many positive attributes of its hybrid design are maintained, higher gas velocity and momentum propagation begin to push its performance envelope into a regime in which both bystander and operator risk may be compromised. Despite this performance drop, the vented 7.62 end cap configuration of the Otter Creek Labs Infinity outperforms the vented configuration of the CGS Helios QD, the Surefire SOCOM762-MINI2, the Energetic Armament VOX-S, and the Rugged Razor762 on this host weapon system.
The Otter Creek Labs Infinity retail package ships without a mount. While this lowers cost and gives the user maximum flexibility, it also requires the user to remain diligent and be responsible for their mounting system choice. Appropriate mount for both practical field use case and blast load dynamics is paramount; the Infinity has a significant degree of early-time venting. This beneficial performance trait may be compromised through the use of mounts that induce undue blast load reflection, such as compensators like the "Cherry Bomb” and others. Use of such devices may increase the effective back pressure of a system by elevating the Alpha parameter; the early-time blast load impulse accumulation inside the first expansion chamber of the silencer. PEW Science encourages the user to contact the silencer manufacturer for a recommended mounting system for their requisite application(s).
The silencer is primarily constructed from Inconel 725 alloy; users may subject the silencer to abusive firing schedules without significant damage. PEW Science has not performed durability testing or evaluation of the Infinity. The user is encouraged to contact the manufacturer for use guidance.
In this review, the Otter Creek Labs Infinity 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.
