SSS.6.185 - Otter Creek Labs Infinity and the Q mini FIX 300 BLK Subsonic (Free Version)
/Otter Creek Labs Infinity on a Q mini FIX 300 BLK with 8-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 Sound Signature Review contains single-test results using the Infinity 762 with its solid end cap and direct thread mount on the Q mini FIX bolt action pistol, chambered in 300 BLK with an 8-inch barrel. Discreet Ballistics 190gr ammunition was used in the test.
Section 6.185.1 contains the Infinity 762 test results and analysis.
Section 6.185.2 contains Suppression Rating comparisons with selected .30 rifle silencers in the subsonic 300 BLK ammunition combustion regime.
Section 6.185.3 contains the review summary and PEW Science laboratory staff technical opinions.
Summary: When paired with the Q mini FIX 8” 300 BLK and fired with Discreet Ballistics 190gr Subsonic Target ammunition, the Otter Creek Labs Infinity with its solid end cap and direct-thread mount achieved a composite Suppression Rating™ of 60.1 in PEW Science testing.
The supersonic .308 performance of the Otter Creek Labs Infinity with the same mount system is detailed in Sound Signature Review 6.178, in which it achieved a composite Suppression Rating of 39.0.
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.
6.185.1 Otter Creek Labs Infinity Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Infinity with its solid end 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 Sound Metric Summary
6.185.1.1 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 the region of peak sound pressure in Figure 1b, for the first three 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. Otter Creek Labs Infinity Bolt Action 300 BLK Muzzle Sound Pressure Signature
Fig 1b. Otter Creek Labs Infinity Bolt Action 300 BLK Muzzle Sound Pressure Signature, Short Time Window
Figure 2a. Otter Creek Labs Infinity Bolt Action 300 BLK Muzzle Sound Impulse Signature
Figure 2b. Otter Creek Labs Infinity Bolt Action 300 BLK Muzzle Sound Impulse Signature
The Otter Creek Labs Infinity has been evaluated in the below end cap configurations on the respective weapon systems:
This report contains an evaluation of the Infinity with the solid 7.62 end cap on an 8-in barrel bolt-action with subsonic 300 BLK ammunition. Use of the Otter Creek Labs Infinity equipped with its vented 7.62 end cap with short-barrel subsonic 300 BLK systems will induce more severe operator and bystander risk.
PEW Science Technology Note: As discussed in the above referenced reports, 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 Centurion Arms, PTR, CAT, CGS, SilencerCo, Surefire, updated recent Dead Air models, 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 and recent Research Supplement 6.184.
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: The same design attributes that allow the Infinity 7.62 to manage high pressure blast load input with high flow rate introduce some difficulty in its management of lower pressure, shorter duration blast load inputs characteristic of the subsonic 300 BLK cartridge. The resulting performance deficiencies are not severe, but they are noteworthy for comparison to other technologies in the research pedigree, as well as for comparison and contrast with the performance of the Infinity on the other platforms with supersonic cartridge loadings. The most significant behavioral difference between operating the Infinity 7.62 with 30 caliber cartridges and 223 caliber cartridges is first-round-pop (FRP).
As discussed in the 7.62 NATO evaluations (6.178) and the 5.56 NATO evaluations (6.179), the OCL Infinity is a 30 caliber silencer greatly optimized for 5.56x45mm combustion jetting. The early time flow rate is high enough such that its high pressure stage becomes saturated earlier relative to input duration with .308 than with 5.56. And, because its late time flow rate is not severely restrictive (like a Polonium, for example), ancillary combustion during FRP propagates further throughout the system prior to quenching. The result of this phenomenon can be examined when comparing solid end-cap blast load impulse accumulations in those two referenced reports.
With subsonic 300 BLK combustion, both the input blast load pressure amplitude and duration are significantly reduced. The high pressure efficiencies of the Infinity are then not fully utilized. The practical result of this is shown in Figure 1, above. Severe FRP jetting occurs early in the measured pressure history (Fig. 1b) and is persistent throughout much of the blowdown duration.
As a result of the early FRP pressure propagation to atmosphere from the presence of extra oxidizer (the oxygen present in the silencer’s internal air volume), the accumulation of blast load impulse occurs early (Fig. 2a). Note that due to the Infinity’s high early time flow rate into multiple stages, the FRP has distinct staged propagation up to accumulation maximum (Fig. 2b). This test data indicates that the Infinity 7.62 is not simply allowing FRP combustion to propagate unimpeded; on the contrary, it most likely indicates that the pressure stages are simply not reaching saturation before subsequent ignition(s). This again highlights the high pressure bias of the OCL Infinity’s performance envelope, despite its second low pressure stage. It is only in the presence of combustion below a certain pressure and duration that this performance attribute is observed.
PEW Science Research Note 2: The net result of the above behavior is compromised FRP suppression performance. After the system is purged of added oxidizer, the low pressure stage of the OCL Infinity can more readily accommodate the short duration low pressure combustion of subsonic 300 BLK cartridges, even on the relatively short 8-in barrel of the Q mini FIX bolt-action rifle. Post-FRP, the consistency of the Infinity’s combustion propagation in the free field is very high.
PEW Science Research Note 3: Note that the blowdown duration from the Otter Creek Labs Infinity is relatively short, as displayed in Figure 1a. This is a consequence of the lack of full stage saturation discussed above, creating a scenario in which its late-time flow rate is higher. Recall its Omega Metric in the 7.62 NATO supersonic ammunition combustion regime is in Zone 5 with the solid end cap.
PEW Science Research Note 4: As a staged hybrid, the OCL Infinity is best compared with rifle silencers that behave in similar ways; the Infinity is not, for example, a staged “gas trap” like the Anthem and Mach series silencers from Liberty Precision Machine. The same lower flow rate (higher back pressure) behavior that results from the Anthem-S2 QD (6.171) design also results in it possessing superior subsonic 300 BLK suppression performance on bolt-action rifles to the Infinity. A particularly interesting comparison to the Infinity is the Combat Application Technologies CAT ODB (6.122). The CAT ODB is also a staged hybrid. However, the SURGE BYPASS technology is shown to quench FRP more expediently than the staged Infinity hybrid technology. The two technologies are very different; the ODB outperforms the Infinity in this regard, as well as in overall average performance on this cartridge.
Another interesting comparison to the Otter Creek Labs Infinity is the Q Half Nelson (6.29), which is the sister-silencer to the Q Trash Panda. The Half Nelson is larger in diameter and longer than the Infinity, and possesses no advanced staged flow elements; it is a purpose-built subsonic 300 BLK silencer. However, the Infinity outperforms the Q Half Nelson both in FRP suppression and overall suppression; and it does so with lower back pressure. The comparison of the Otter Creek Labs Infinity and the Q Half Nelson serves as an excellent case study in silencer industry technological advancement driven by both design evolution and user requirements. With more primitive designs like the Nelson series, it takes significant baffle quantity and volume to produce superior suppression, as showcased in the Q Full Nelson test report (6.99).
There are other purpose-built subsonic 300 BLK silencers with older technologies that still offer very competitive performance. For example, the Surefire SOCOM300-SPS (6.57) outperforms the Otter Creek Labs Infinity in both FRP suppression and overall suppression with subsonic 300 BLK. However, the SOCOM300-SPS has significantly higher back pressure than the Infinity, and is almost 8 inches long. Again, 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, and now Otter Creek Labs and others, offer users more versatile silencer solutions.
PEW Science Research Note 5: An important comparison of Infinity subsonic 300 BLK performance is with that of the Diligent Defense Enticer-S (6.89). The two silencers have similar overall Composite Suppression Ratings on this host weapon platform. However, the Infinity outperforms the slightly longer Enticer-S in FRP suppression and overall muzzle suppression. The Infinity does this with significantly lower back pressure. This is also an interesting performance comparison because of the similarity in performance of the two silencers with supersonic 7.62 NATO suppression.
The Otter Creek Labs Infinity shooter’s ear suppression performance is examined in the full Member Version of this report. Direct comparisons with other silencers fired with subsonic 300 BLK from an 8-inch barrel are provided in Section 6.185.2, below.
6.185.2 Suppression Rating Comparison - Subsonic 300 BLK
The Otter Creek Labs Infinity was developed with a focus on high pressure sound signature reduction (PEW Science Suppression Rating), with low back pressure. As previously discussed, its subsonic sound signature suppression performance is somewhat less robust than some high performing systems for the cartridge. 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 shown in no particular order.
Figure 6. Suppression Rating Comparisons Of .30 Rifle Silencers Using PEW-SOFT 300 BLK Subsonic Test Data
The holistic performance of the Otter Creek Labs Infinity with subsonic 300 BLK is relatively close to that of both the Diligent Defense Enticer-S (6.89) and the wiped Energetic Armament VOX S (6.38). The Infinity outperforms the Enticer-S in FRP control, and also outperforms the smaller VOX S silencer even when the VOX is using a wipe. Without a wipe, the VOX S (6.25) is significantly louder with extreme FRP.
In pure muzzle suppression performance, the OCL Infinity is outperformed by the Banish 30 Gold (6.70), Surefire SOCOM300-SPS (6.57), Diligent Defense Enticer L (6.88), and CAT ODB (6.122). Of those silencers, the CAT ODB provides the most advanced FRP control, with the highest gross flow rate. It is somewhat of an outlier in the Standard research pedigree. The Enticer L and Banish 30 Gold have severe FRP, with the FRP from the SOCOM300-SPS being moderate on this host weapon, even with its somewhat older technology.
As discussed in Research Note 4 of this report, another interesting comparison to the Otter Creek Labs Infinity is the Q Half Nelson (6.29), which is the sister-silencer to the Q Trash Panda. The Half Nelson is larger in diameter and longer than the Infinity, and possesses no advanced staged flow elements; it is a purpose-built subsonic 300 BLK silencer. However, the Infinity outperforms the Q Half Nelson both in FRP suppression and overall suppression; and it does so with lower back pressure. The comparison of the Otter Creek Labs Infinity and the Q Half Nelson serves as an excellent case study in silencer industry technological advancement driven by both design evolution and user requirements. With more primitive designs like the Nelson series, it takes significant baffle quantity and volume to produce superior suppression, as showcased in the Q Full Nelson test report (6.99).
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, and now Otter Creek Labs and others, offer users more versatile silencer solutions.
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.
6.185.3 Review Summary: Otter Creek Labs Infinity on a Q mini FIX 300 BLK with 8-in Barrel
When paired with the Q mini FIX 8” 300 BLK and fired with Discreet Ballistics 190gr Subsonic Target ammunition, the Otter Creek Labs Infinity with its solid end cap and direct-thread mount achieved a composite Suppression Rating™ of 60.1 in PEW Science testing.
The supersonic .308 performance of the Otter Creek Labs Infinity with the same mount system is detailed in Sound Signature Review 6.178, in which it achieved a composite Suppression Rating of 39.0.
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. With subsonic 300 BLK, the Infinity is able to compete with many conventional silencers, while exhibiting some performance deficiencies in first-round-pop (FRP) control.
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.
Note that the performance examined in this report is with the solid 7.62 end cap. Use of the vented Infinity end cap with subsonic 300 BLK will increase operator and bystander risk metrics.
The same design attributes that allow the Infinity 7.62 to manage high pressure blast load input with high flow rate introduce some difficulty in its management of lower pressure, shorter duration blast load inputs characteristic of the subsonic 300 BLK cartridge. The resulting performance deficiencies are not severe, but they are noteworthy for comparison to other technologies in the research pedigree, as well as for comparison and contrast with the performance of the Infinity on the other platforms with supersonic cartridge loadings. The most significant behavioral difference between operating the Infinity 7.62 with 30 caliber cartridges and 223 caliber cartridges is FRP.
As a staged hybrid, the OCL Infinity is best compared with rifle silencers that behave in similar ways; the Infinity is not, for example, a staged “gas trap” like the Anthem and Mach series silencers from Liberty Precision Machine. The same lower flow rate (higher back pressure) behavior that results from the Anthem-S2 QD design also results in it possessing superior subsonic 300 BLK suppression performance on bolt-action rifles to the Infinity. A particularly interesting comparison to the Infinity is the Combat Application Technologies CAT ODB. The CAT ODB is also a staged hybrid. However, the SURGE BYPASS technology is shown to quench FRP more expediently than the staged Infinity hybrid technology. The two technologies are very different; the ODB outperforms the Infinity in this regard, as well as in overall average performance on this cartridge. Another interesting comparison to the Otter Creek Labs Infinity is the Q Half Nelson, which is the sister-silencer to the Q Trash Panda. The Half Nelson is larger in diameter and longer than the Infinity, and possesses no advanced staged flow elements; it is a purpose-built subsonic 300 BLK silencer. However, the Infinity outperforms the Q Half Nelson both in FRP suppression and overall suppression; and it does so with lower back pressure. The comparison of the Otter Creek Labs Infinity and the Q Half Nelson serves as an excellent case study in silencer industry technological advancement driven by both design evolution and user requirements. With more primitive designs, like the Nelson series, it takes significant baffle quantity and volume to produce superior suppression, as showcased in the Q Full Nelson test report.
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 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.
