SSS.6.129 - Combat Application Technologies CAT/WB/A1/718 and the MK18 5.56x45mm Short Barrel Automatic AR15 Rifle
/Combat Application Technologies CAT/WB/A1/718 on the MK18 5.56x45mm AR15 with 10.3-in Barrel
The CAT/WB/A1/718 (“WB” in this report) is designed by Combat Application Technologies (CAT). It is a compact (“K”) 223 caliber centerfire rifle silencer, intended to suppress the 5.56x45mm cartridge, with no barrel length restrictions. It has a 1.6-inch diameter and the silencer core is 5.2 inches long (5.4 inches long, including its external flash hiding features). The silencer is HUB compatible (1.375”-24 tpi threading). Therefore, the user may install a variety of 3rd-party mounting systems and muzzle devices with the silencer. Length of the total system will vary, depending on mount choice. For example, use of the CAT/TSF X threaded coupler will result in a total system length of 5.8 inches. The entirety of the silencer is DMLS (3D-printed) from a proprietary Inconel alloy. The factory specified weight of the CAT/WB/A1/718 Inconel core is 12.6 ounces. The CAT/WB/A1 Titanium core model is also available, and weighs 6.9 ounces. Geometry is identical. The third-party flash hider used in testing resulted in a tested system length of approximately 6.1 inches. Both CAT/WB/A1 models 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 for public research is generated with funding provided by PEW Science members. Any test data that is generated with any portion of private funding contains this disclosure. The testing and data production for this Sound Signature Review white paper was funded in part by PEW Science Project PEW-CAT-059-001-23. Therefore, data pertaining to the CAT/WB/A1/718 in this Sound Signature Review is published with the express written permission of Combat Application Technologies.
This Sound Signature Review contains single-test results using the WB mounted with a 3-prong flash hider on the MK18 Automatic AR15 rifle, chambered in 5.56x45mm NATO with a 10.3-inch barrel. Federal XM193 55gr ammunition was used in the test. The standard PEW Science MK18 test host weapon system is described in Public Research Supplement 6.51.
Section 6.129.1 contains the WB test results and analysis.
Section 6.129.2 contains Suppression Rating comparisons of the WB with dedicated 223 and 30 caliber silencers on the current market, including the PWS BDE 556, CAT ODB, Aero Precision Lahar-30L, Lahar-30, HUXWRX FLOW 762 Ti, Maxim Defense DSX, Thunder Beast Dominus, KAC 5.56 QDC, CGS SCI-SIX, Dead Air Nomad-30, YHM Turbo T2, Dead Air Sandman-S, HUXWRX FLOW 556k, Energetic Armament ARX, KAC QDSS-NT4, Rugged Razor556, Otter Creek Labs Polonium and Polonium-K, Surefire SOCOM556-RC2, HUXWRX HX-QD 556 and HX-QD 556k, Q Trash Panda, CGS Helios QD, SilencerCo Saker 556, Rugged Razor762, and others.
Section 6.129.3 contains an article summary and PEW Science laboratory staff opinions.
Summary: When paired with the 10.3-in barrel MK18 and fired with Federal XM193, the CAT/WB/A1/718 achieved a composite Suppression Rating™ of 35.3 in PEW Science testing.
When paired with the 14.5-in barrel M4A1 and fired with Federal XM193, the CAT/WB/A1/718 achieved a composite Suppression Rating™ of 41.0 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
6.129.1 CAT/WB/A1/718 Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the WB is shown in Table 1. The data acquired 1.0 m (39.4 in) left of the muzzle is available for viewing to all. This is a members-only review and includes pressure and impulse waveforms measured at the shooter’s ear. PEW Science thanks you for your support; further testing, research, and development of PEW-SOFT and the Silencer Sound Standard is made possible by members like you!
Table 1. CAT/WB/A1/718 Sound Metric Summary
6.129.1.1 SOUND SIGNATURES AT THE MUZZLE
Real sound pressure histories from a 6-shot test acquired with PEW-SOFT™ are shown below. Six cartridges were loaded into the magazine, the fire control group positioned to single-shot, and the weapon was fired until the magazine was empty and the bolt locked back on the follower of the empty magazine. Only five shots are considered in the analysis. The signatures of Shot 6 are displayed in the data presentation but are not included in the analysis to maintain consistency with the overall PEW Science public dataset and bolt-closing signatures. 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 6 shots with the WB are shown in Figure 1a. The sound signatures of Shot 1 and Shot 2 are shown in Figure 1b, in early time. The real sound impulse (momentum transfer potential) histories from the same 6-shot test are shown in Figure 2a. In Figure 2b, a shorter timescale is shown comparing the impulse of Shot 1 to that of Shot 2 and Shot 3.
Fig 1a. CAT/WB/A1/718 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Pressure Signature
Fig 1b. CAT/WB/A1/718 5.56x45mm NATO MK18 Automatic Rifle Sound Pressure Signature
Figure 2a. CAT/WB/A1/718 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature
Figure 2b. CAT/WB/A1/718 5.56x45mm NATO MK18 Automatic Rifle Muzzle Sound Impulse Signature
Similarly to those noted from the CAT ODB on the MK18 (6.120), the measured signatures from the CAT WB on this platform indicate atypical behavior. The ODB is a 7.62mm (30 caliber) silencer, whereas the WB is a 5.56mm (223 caliber) silencer. Both silencers behave like dedicated-bore 5.56mm silencers on the MK18, and both share some attributes common in signatures generated by “high flow rate” silencers. As was discussed in the aforementioned ODB MK18 white paper, these behaviors are highly atypical because these silencers from CAT are not Flow Through silencers, and the external muzzle signatures indicate this.
Both silencers present the following behavior on the standard MK18 weapon system. ODB and WB differentiation is given in bold.
Early combustion signature phenomenology presents as typical (Fig. 1b), along with relatively typical coupling of bullet shock and initial jetting. The initial jetting from the WB is of lower amplitude than from the ODB.
The immediate negative phase characterized by consistent rarefaction begins primary jetting with an initial delay (approximately 30 ms, Fig. 1b). Initial FRP divergence from the WB is slightly more severe than from the ODB.
Jet accumulation is linear in early time with minimal first round pop (FRP) divergence. This is true for both silencers.
FRP impulse accumulation (Fig. 2b) is of unusually low amplitude, with a similar rate to that of subsequent shots after initial jetting. This is the case for both silencers.
Consistency in impulse accumulation is notable; external flow anomalies are not evident. Flow normalization is slightly superior with the larger ODB, compared with the WB.
Finally, bolt carrier group (BCG) closing signatures, in late time, are significantly delayed (Fig. 1a). The bolt closing time with the WB is slightly faster than with the ODB.
The above external pressure signatures, and comparisons of the CAT WB behavior with that of the CAT ODB on the same weapon system, highlight the below simultaneous high-level conclusions:
Both CAT silencers possess the gross muzzle signature suppression characteristics of a high performance dedicated bore 5.56mm silencer on this short barrel weapon system, like a Surefire SOCOM556-RC2 (6.52).
Both silencers produces signature consistency with extremely controlled gas momentum, like an Otter Creek Labs Polonium (6.75).
Both silencers produce low-amplitude FRP impulse accumulation like a Thunder Beast Dominus (6.105).
Both silencers produce weapon kinematics similar to Flow Through silencers such as the HUXWRX FLOW 556k (6.83) and HUXWRX FLOW 762 Ti (6.114).
The CAT WB accomplishes the same gross behavioral traits as the CAT ODB on the MK18 weapon system in a significantly smaller design envelope. This is notable, and highly unusual. The above four conclusions, common to both the 30 caliber ODB and the 223 caliber WB, occurring simultaneously on the MK18, are the result of the CAT SURGE BYPASS technology used in both silencers.
PEW Science Research Note 1: The SURGE BYPASS technology in the ODB and WB silencers consists of multistage pressure reducing regions with multiple stagnation relief zones. Early blast chamber venting to reduce the so-called alpha parameter appears to facilitate the early stage, post-uncorking. The SURGE BYPASS technology in the WB is of slightly varied design compared with that in the ODB (see Research Note 3). It is important to note the differences between so-called Flow Through technology and SURGE BYPASS. In a Flow Through silencer, gas is routed early and continuously through a toroidal overlapping path for final distal exit; heat transfer being a significant performance parameter. With such silencers, the alpha parameter, characterizing internal early time shock propagation and flow rate, is minimized with the externally measured PEW Science Back Pressure Metric, Omega also minimized.
However, in a CAT silencer with SURGE BYPASS technology, while alpha is minimized and managed, the resulting final externally measured Omega Metric may not drop to levels usually seen in a Flow Through silencer. In fact, gross exterior impulse accumulation rates of the CAT ODB on the MK18 are extremely similar to that of the aforementioned Surefire SOCOM556-RC2 and the Q Trash Panda (6.61), whereas the accumulation rates of the CAT WB on the MK18 are similar to that of the Surefire SOCOM556-RC2 and the Liberty Precision Machine Torch with its solid end cap (6.126).
PEW Science Research Note 2: The measured data in this report illustrates a combination of behaviors only previously characterized by the PEW Science laboratory in the CAT ODB research. PEW Science postulates that the SURGE BYPASS technology may represent one of the most significant advancements in semiautomatic rifle silencer technology in the pedigree, to date. For a silencer to possess all of the above mentioned traits on the MK18, simultaneously, is highly atypical, especially for a 30 caliber silencer in the case of the ODB. And, as the behavior also occurs in the shorter CAT WB, at least some portion of the technology is likely to have scaling properties across geometries. No rifle silencers tested by the PEW Science laboratory, to date, behave like the CAT ODB and WB on the MK18. To date, it has only been reconfigurable silencers that can approach this type of behavior. For example, the aforementioned Liberty Precision Machine Torch can achieve high gross signature suppression at the muzzle and somewhat reduced bolt speed with its solid end cap, but the Torch requires an end cap change to drive down the hazard to the weapon operator. With its vented end cap, the Torch now loses gross suppression efficiency in the entire sound field. The SURGE BYPASS technology is able to excel in all three performance areas (bystander hazard, shooter hazard, and weapon function) simultaneously with no physical change. However, there are technology differences between the CAT ODB and WB (see Research Note 3).
PEW Science Research Note 3: The SURGE BYPASS technology implementation in the WB is slightly different than in the ODB. In the WB A1 implementation of the technology, the staged design has been minimized. PEW Science postulates that the simplification of the the technology in the WB, when compared to that of the ODB, results in more direct performance scaling across 5.56x45mm barrel lengths in both signature suppression and back pressure reduction. M4A1 14.5-in Mid-Gas evaluation of the WB is presented in 6.130. Further research is needed to characterize other combustion regimes. Regardless of the change in technology implementation between the two silencers, the shorter design envelope of the WB model shows a high degree of performance efficacy across barrel lengths, similar to how the CAT ODB demonstrates “pressure agnostic” behavior in its 5.56x45mm MK18 and subsonic 300 BLK performance envelopes. The ability of silencers to exhibit high performance in a variety of blast load environments (varying both pressure and duration, along with varied shock impulse accumulation with barrel length variation) is relatively uncommon. The Surefire SOCOM556-RC2 (6.52 and 6.128) demonstrates potential challenges with this with varied barrel length, as does the HUXWRX (OSS) HX-QD 762 (6.41 and 6.45) with varied combustion regimes. CGS Hyperion Technology in the Helios QD also demonstrates such pressure-dependent performance variation (albeit variable with muzzle orifice location in that technology). Research is ongoing.
PEW Science Research Note 4: The FRP signature to bystanders from the CAT WB on the standard MK18 is slightly more severe than that from the CAT ODB. Both silencers possess nominal FRP severity when compared to that of subsequent shots.
PEW Science Research Note 5: The holistic suppression performance of the CAT WB on this weapon system eclipses that of many dedicated 5.56mm silencers evaluated by PEW Science, to date, especially for the size of the silencer. The CAT WB is a shorter "kurtz” or “K” model and notably, also eclipses the performance of many 7.62mm silencers on this platform. The closest holistic performance competitors to the CAT WB on the MK18 are the CAT ODB and the HUXWRX FLOW 762 Ti (both 7.62mm silencers that are larger). The Liberty Precision Machine Torch is somewhat capable of extremely competitive holistic performance, but as described above, the end cap must be changed for it to achieve certain performance parameters, which results in performance in other areas dropping.
PEW Science Research Note 6: As noted in the Liberty Precision Machine Torch white paper (6.126), it is important to note that severity comparisons given herein are valid in the free field. Further research is being conducted on the efficacy of different high flow system technologies and the respective hazards produced near reflecting surfaces. This is one of the reasons why PEW Science postulates the SURGE BYPASS technology in the CAT ODB and WB silencers represents a potential departure from typical performance envelopes on reciprocating rifles. In the case of HUXWRX Flow-Through technology, reducing hazard to the weapon operator with a high gross flow rate is well studied in the free field. The potential of maintaining a high flow rate, reducing weapon over-function, and still maintaining a high degree of muzzle suppression, is a significant milestone in the state of practice. PEW Science considers these types of parametric performance evaluations critical to the future of suppressed small arms development.
PEW Science Research Note 7: As in all semiautomatic AR15 weapon testing, a second pressure pulse originates from the ejection-port signature of the weapon and it occurs early enough in time such that its waves coalesce with that of the muzzle signature. However, in late time (at approximately 85 ms in Figure 1a) the mechanical noise of the bolt closing is observed. The pressure signature of Shot 6 does not display this event due to the bolt remaining open after the sixth and final round is fired from the magazine. For a silencer like the WB to produce these kinematics is atypical. The BCG cycle speed, overall, is much slower than with a typical rifle silencer (with the caveats given in Research Note 6, below. Note that the Member version of this article contains further kinematics discussion).
PEW Science Research Note 8: The closing time of the MK18 bolt is directly related to the flow restriction of a silencer for a given weapon system. PEW Science has determined bolt closing time variation from the unsuppressed state to be a reliable indicator of silencer back pressure, with strong correlation with the PEW Science Back Pressure Metric, Omega and the alpha parameter. However, PEW Science has also determined that the indicator is unreliable upon upper receiver fouling. Sound signatures are not influenced by this fouling, as these kinematics occur in late time, after gas venting to atmosphere. Momentum transfer, weapon condition (upper receiver fouling), and other factors, can significantly influence bolt closing time. PEW Science urges the reader to exercise extreme caution if using the published bolt closing time to make determinations regarding silencer flow restriction (back pressure) or weapon system kinematics. This type of calculation may provide erroneous results, as the weapon condition at the time of each test is not published data. The time-scale duration showing bolt closing time is only published by PEW Science such that the signature data pedigree may be verified. Weapon function information provided by PEW laboratory personnel is provided in the final section of this article.
The shape, timing, and magnitudes of the early-time pressure pulses and overall shape of the impulse waveforms measured at the muzzle, from shot-to-shot, are very consistent. The consistency of the waveform amplitudes highlight the silencer’s overall sound performance consistency at the muzzle after the FRP, as well as the relative consistency of the tested automatic rifle firearm configuration.
As typically indicated, first-round sound signatures always differ from subsequent shots, as the atmosphere within the silencer changes. The FRP phenomenon cannot always be shown by viewing only the peak sound pressure. This is one of the reasons why The Silencer Sound Standard requires examining multiple sound signature metrics. Ammunition consistency can play a role in the determination of FRP, however, the close examination of measured pressure and impulse waveforms typically excludes ammunition from the possible factors influencing true FRP, due to the relative consistency of most high quality factory ammunition.
PEW Science Research Note 9: Note that the muzzle Suppression Rating of the CAT WB is 34.1 and the at-ear Suppression Rating is 27.9; almost the same zone on the Suppression Rating Dose Chart. Unlike many rifle silencers, the high early time flow rate of the CAT WB, coupled with its above-average muzzle suppression, is extremely beneficial to the sound signature at the shooter’s ear on the standard MK18 weapon system. The resulting back pressure of the CAT WB is low, and the muzzle signature is suppressed adequately enough, that the weapon operator is subjected to less significant hearing damage risk. The CAT WB produces a shooter’s ear Suppression Rating on an untuned MK18 only bested by the CAT ODB and HUXWRX FLOW silencers in the free field. The CAT WB possesses a higher degree of bystander suppression than the FLOW silencers. The signatures measured at the shooter’s ear are presented below.
6.129.1.2 SOUND SIGNATURES AT SHOOTER’S EAR
Real sound pressure histories from the same 6-shot test acquired with PEW-SOFT at the shooter’s ear are shown below. Again, the waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science testing is 1.0 MS/s (1 MHz).
The primary sound signature pressure histories at the ear for all 6 shots are shown in Figure 3. The primary sound signature history is shown in Figure 3a. An annotated timescale is displayed in Figure 3b, for Shots 1 and 2. The real sound impulse (momentum transfer potential) histories at the ear from the same 5-shot test are shown in Figure 4. Again, full and short timescales are shown.
Figure 3a. CAT/WB/A1/718 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Pressure Signature
Figure 3b. CAT/WB/A1/718 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Pressure Signature, Short Time Window
Figure 4a. CAT/WB/A1/718 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Impulse Signature
Figure 4b. CAT/WB/A1/718 5.56x45mm NATO MK18 Automatic Rifle Ear Sound Impulse Signature Peaks
The waveforms measured at the shooter’s ear with the CAT WB on the standard untuned MK18, like with the CAT ODB, indicate Flow Through weapon function and signature characteristics with conventional high performance silencer behavior. As discussed in the main section of this report, this is a consequence of the SURGE BYPASS technology in the two silencers. The alpha parameter is minimized, without regard to gross Omega Metric. The end result mirrors high flow rate silencer behavior with significant lack of muzzle signature contribution to the operator hazard.
PEW Science Research Note 10: Similar notes that were provided in the ODB MK18 whitepaper are provided below, in reference to the above WB MK18 data. This time, they are occurring with a “K” silencer.
Figure 3b, above, displays Shot 1 and Shot 2 at full time scale. It is important to note the following:
Ground reflection is revealed; this is only possible due to low amplitude blow down at the time regime of interest. This indicates that the nested blowdown and ejection port pulses have diminished to levels of lower hazard, quickly.
Mechanical noise begins to dominate the shooter’s ear signature, early. Note the clear impact of the BCG with the end of the receiver extension prior to forward travel (~48 ms). This event is only visible without significant coalescence of signature from other events; therefore, silencers like the WB, ODB, Torch, and FLOW series show this phenomenon. Conventional silencers on this weapon system will not. Note that this is one of the reasons testing in the free field is paramount, and one of the reasons the Silencer Sound Standard and MIL-STD require such testing.
The BCG returns to battery in very late time, as previously discussed in Research Note 7. The BCG speed is reduced from typical. For a similar bystander suppression performance as a CGS SCI-SIX and Surefire SOCOM556-RC2, in a smaller design envelope, the CAT WB is allowing the weapon to cycle like a Flow-Through silencer.
The above alludes to weapon kinematics. Signature characteristics expressed in momentum transfer potential (impulse) measured at the operator’s location are displayed in Figure 4. Note that the WB produces less post-peak FRP divergence than the ODB. For its size and tighter bore, the WB manages ejection port signature with notable consistency. The performance can be described as very balanced with regard to bystander and operator hazard.
One of the primary differences between the ODB and the WB (besides the overall size and bore aperture) is the overall signature severity from the silencer and the ejection port on the standard MK18. The two sources of overpressure are not only different in amplitude, but different in timing. For its size, the WB achieves notable hazard reduction the weapon operator. The reduction in length, coupled with a tighter bore, drops the shooter’s ear Suppression Rating by a relatively low amount when compared to the ODB.
In summary, the CAT WB, to the shooter, provides an operator experience on the MK18 that is a cross between a CGS SCI-SIX, Surefire SOCOM556-RC2, and a HUXWRX HX-QD 556 / FLOW 762 Ti, in a smaller size envelope. That is the most succinct way to describe the holistic signature, gas dynamics, and hazard conditions of the system. Another performance analog is that the WB is a "smaller ODB, meant for 5.56mm weapons.” It is likely that if the standard MK18 weapon system is tuned, the CAT WB system will achieve even higher levels of performance. The reader is encouraged to examine previous Research Note 6 for postulations regarding these performance combinations, comparisons, and utility of the data for their use case.
PEW Science Research Note 11: In PEW Science laboratory testing of the WB (and of the ODB), FRP severity differential was completely masked to the weapon operator on the standard MK18.
6.129.2 Suppression Rating Comparison (5.56x45mm from the MK18)
Figure 6 presents a comparison of the PEW Science Suppression Rating of the CAT/WB/A1/718 to that of other rifle silences on the MK18 automatic AR15 rifle. The standard PEW Science MK18 test host weapon system is described in Public Research Supplement 6.51.
Figure 6. Suppression Rating Comparisons of the CAT/WB/A1/718 and other silencers, Using PEW-SOFT 5.56x45mm Supersonic Test Data and PEW Science Analysis
Figure 6 presents detailed PEW Science Suppression Ratings, computed at the muzzle and ear, for the listed silencers. The Suppression Rating is a holistic parameter that captures human inner ear damage risk potential from a measured impulsive overpressure signature during the entire time regime of weapon operation, including combustion, complete blowdown, and all mechanical operation, including the carrier group returning to battery, in the true free field. The parameter may be used with the dose chart at the beginning of this report.
From the above data, it can be concluded that the CAT WB exhibits extremely competitive performance on the standard untuned MK18 weapon system as a dedicated 5.56mm silencer, and eclipses the holistic performance of several larger 7.62mm silencers:
The CAT WB has a smaller design envelope, but provides bystander signature severity similar to that of the CGS SCI-SIX (6.101) and Surefire SOCOM556-RC2 (6.52).
The CAT SURGE BYPASS technology in the WB allows Flow Through-like weapon kinematics and ejection port signature hazard reduction like a HUXWRX FLOW silencer, with the gas momentum control of an Otter Creek Labs Polonium (6.75) which has much higher backpressure.
The closest holistic performance competitors to the CAT WB on the MK18 are the CAT ODB and the HUXWRX FLOW 762 Ti (both 7.62mm silencers that are larger). The Liberty Precision Machine Torch is somewhat capable of extremely competitive holistic performance, but as previously noted, the end cap must be changed for it to achieve certain performance parameters, which results in performance in other areas dropping.
PEW Science Research Note 12: The CAT WB, holistically, outperforms most silencers tested on the MK18 by PEW Science, to date, in signature hazard reduction. For a "K” silencer, its performance on the MK18 is extremely significant. Due to the breadth of the Silencer Sound Standard testing and analysis pedigree, the reader is encouraged to examine the spectrum over which suppression performance on the MK18 has been demonstrated. There exist silencers evaluated on the 5.56x45mm short barrel rifle platform that have significantly lower performance. Because the PEW Science Suppression Rating is a damage risk criterion (DRC), a lower Suppression Rating indicates a higher personnel hazard in the free field. Therefore, silencers such as the Energetic Armament ARX (6.82), the Rugged Razor762 (6.58), and WARCOMP-equipped Surefire silencers, are postulated to be more hazardous to the unprotected ear than silencers like the CAT WB. To iterate, the Suppression Rating is a DRC - it is not a subjective quantity; it is an objective quantification of hearing damage risk potential.
As shown in Figure 6, the Suppression Rating at the shooter’s ear may be significantly influenced by the ejection port signature from the MK18; all other things equal. For details on performance increases that are possible when “tuning” an AR-15 weapon system for a silencer, please see Review 6.111. It is important to note that not all silencers will possess a significant increase in shooter’s ear Suppression Rating from weapon tuning. Signature at the operator’s head is a function of both muzzle and ejection port signatures from the AR-15 weapon system. Specific weapon system parameters will dictate modification efficacy.
In summary, the CAT WB provides an operator experience on the MK18 that is a cross between a CGS SCI-SIX, Surefire SOCOM556-RC2, and a HUXWRX HX-QD 556 / FLOW 762 Ti, in a smaller design envelope. Further laboratory testing of the WB is presented with the M4A1 14.5-in Mid-Length gas rifle in 6.130.
6.129.3 Review Summary: CAT/WB/A1/718 on the MK18 5.56x45mm AR15 with 10.3-in Barrel
When paired with the 10.3-in barrel MK18 and fired with Federal XM193, the CAT/WB/A1/718 achieved a composite Suppression Rating™ of 35.3 in PEW Science testing.
PEW Science Laboratory Staff Opinion:
The CAT/WB/A1/718 (CAT WB) is a compact and extremely advanced 5.56mm machine gun rated rifle silencer that exhibits significant back pressure reduction and sound signature suppression performance, for its size. Its sound suppression performance on a short barrel 5.56x45mm rifle is significant. Notably, the CAT SURGE BYPASS technology in the silencer appears to balance high flow rate behavior with superior overall signature suppression. The silencer is available in two 3D-printed material options; proprietary Inconel alloy and Titanium. The weights of both models are notable. The CAT WB represents one of the most advanced systems evaluated by PEW Science, to date.
The measured test data presented in this white paper indicate that the CAT WB is producing the following high-level system behavior. All occur simultaneously:
Like the larger 7.62mm CAT ODB, the smaller 5.56mm CAT WB possesses the gross muzzle signature suppression characteristics of a high performance dedicated bore 5.56mm silencer on this short barrel weapon system, like a Surefire SOCOM556-RC2, with extremely controlled gas momentum, like an Otter Creek Labs Polonium. It produces low-amplitude FRP impulse accumulation like a Thunder Beast Dominus, with weapon kinematics similar to Flow Through silencers such as the HUXWRX FLOW 556k and HUXWRX FLOW 762 Ti. This behavior, occurring simultaneously on the MK18, is the result of the CAT SURGE BYPASS technology in the WB.
The SURGE BYPASS technology implementation in the WB is slightly different than in the ODB. In the WB A1 implementation of the technology, the staged design has been minimized. PEW Science postulates that the simplification of the the technology in the WB, when compared to that of the ODB, results in more direct performance scaling across 5.56x45mm barrel lengths in both signature suppression and back pressure reduction. M4A1 14.5-in Mid-Gas evaluation of the WB is presented in 6.130. Further research is needed to characterize other combustion regimes. Regardless of the change in technology implementation between the two silencers, the shorter design envelope of the WB model shows a high degree of performance efficacy across barrel lengths, similar to how the CAT ODB demonstrates “pressure agnostic” behavior in its 5.56x45mm MK18 and subsonic 300 BLK performance envelopes.
Another unusual characteristic of the CAT WB is that like the ODB, is it is offered with so-called HUB universal mount threading at the proximal end. It is not typical for high performance silencers with such technology to use non-proprietary mounts, because mount choice can sometimes significantly influence silencer and suppressed weapon system performance. One unique characteristic of the SURGE BYPASS technology is that the alpha parameter minimization is postulated to be robust with mount choice. In other words, different mounting schemes may not adversely influence SURGE BYPASS behavior as much as some other technologies such as Flow-Through. Further laboratory evaluations are needed. The presented test data was acquired using a third-party flash hider, for reference.
There are specific physical characteristics of the CAT WB that are notable, and may be useful for end users to consider, given the somewhat similar gross free field risk metrics and weapon kinematics to the CAT ODB and HUXWRX FLOW 762 Ti. For example, the factory-specified core weights for the CAT WB are lighter than many competing models, and the length is similar to some “K” silencers. Like the CAT ODB, the WB is available in both Inconel and Titanium versions. The Titanium version of the WB, at a specified core weight of only 6.9 ounces, is extremely light and leaves a significant amount of leeway in mount system weight for users to match the full system weight of a variety of systems. The Inconel version of the WB is 5.7 ounces heavier. Users should note that, in general, the durability and sparking performance of Inconel vs. Titanium silencers may be significant.
In this review, the CAT/WB/A1/718 performance metrics depend upon suppressing a supersonic centerfire rifle cartridge on a short barrel gas-operated rifle, which is an incredibly difficult task. PEW Science encourages the reader to remain vigilant with regard to all supersonic centerfire rifle suppression claims. The gas volume and combustion products created by the firing of the supersonic 5.56x45mm cartridge are significant; the measured pressure and impulse magnitudes, and their durations, illustrate this fact. Silencer performance on automatic (reciprocating) rifles depends on many factors. Weapon configuration may significantly influence total suppressed small arm system performance.
The hearing damage potential of supersonic centerfire rifle use is significant. PEW Science encourages the reader to consider the Suppression Rating when deciding on an appropriate silencer and host weapon combination for their desired use.
