SSS.6.141 - Combat Application Technologies CAT/SR/A1 and the Beretta 21A
/Combat Application Technologies CAT/SR/A1 on a Beretta 21A Subcompact Semiautomatic Pistol
The CAT/SR/A1 (“SR” in this report) is designed by Combat Application Technologies (CAT). It is a 22 caliber rimfire silencer, intended to suppress cartridges ranging from .22LR to 5.7x28mm. It has a 1.05-inch diameter and is 5.6 inches long, including its external end cap features. The silencer’s integrated mount and core is DMLS (3D-printed) Titanium and the removable end cap is aluminum. The silencer may be installed on host weapons threaded 1/2”-28-tpi. The silencer weighs 2.8 ounces, as tested. The CAT/SR/A1 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/SR/A1 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 CAT SR mounted to the Beretta 21A subcompact semiautomatic pistol, chambered in .22LR with a 2.4-inch barrel. CCI Standard Velocity 40gr ammunition was used in the test.
- Section 6.141.1 contains the CAT SR test results and analysis.
- Section 6.141.2 contains Suppression Rating comparisons with selected .22 rimfire silencers in the subsonic cartridge regime.
- Section 6.141.3 contains the review summary and PEW Science laboratory staff technical opinions.
Summary: When paired with the Beretta 21A subcompact semiautomatic pistol and fired with CCI SV .22 LR ammunition, the CAT/SR/A1 achieved a composite Suppression Rating™ of 87.6 in PEW Science testing.
The bolt-action rifle rimfire performance of the CAT/SR/A1 is detailed in Sound Signature Review 6.140, in which it achieved a composite Suppression Rating of 96.8.
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
6.141.1 CAT/SR/A1 Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the CAT SR 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/SR/A1 Sound Metric Summary
6.141.1.1 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 and the weapon was fired until the magazine was empty; the Beretta 21A pistol does not possess a last round bold hold open feature, and thus the slide does not lock back on the last round fired. Only five shots are considered in the analysis, to maintain consistency with the overall PEW Science public dataset. 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 are shown in Figure 1a. A zoomed-in timescale displays the region of peak sound pressure in Figure 1b, for the first two shots. The real sound impulse (momentum transfer potential) histories from the same 6-shot test are shown in Figure 2. Again, full and short timescales are shown.
Fig 1a. CAT/SR/A1 Subsonic .22 LR Beretta 21A Subcompact Semiautomatic Pistol Muzzle Sound Pressure Signature
Fig 1b. CAT/SR/A1 Subsonic .22 LR Beretta 21A Subcompact Semiautomatic Pistol Muzzle Sound Pressure Signature, Short Time Window
Figure 2a. CAT/SR/A1 Subsonic .22 LR Beretta 21A Subcompact Semiautomatic Pistol Muzzle Sound Impulse Signature
Figure 2b. CAT/SR/A1 Subsonic .22 LR Beretta 21A Subcompact Semiautomatic Pistol Muzzle Sound Impulse Signature
The Combat Application Technologies CAT/SR/A1 is a rimfire silencer that exhibits enhanced performance characteristics and incorporates elements of CAT Surge Bypass technology in its design. In the longer barrel rimfire bolt-action test of the silencer (6.140), the CAT SR produced an extremely low amplitude signature and no apparent first-round-pop (FRP). In this short barrel rimfire semiautomatic pistol test using the Beretta 21A, much of the same behavior from the CAT SR is observed, which is atypical for a rimfire silencer. Notable performance attributes observed in the above test data include:
Significantly suppressed primary muzzle blast pressure amplitude (Figure 1).
Extremely consistent gas momentum with low blast impulse accumulation throughout the duration of primary jetting (Fig. 2b).
FRP is nominally measurable in gas momentum (Fig 2b), but is masked and nullified to observers.
Unusually higher amplitude mechanical signatures from pistol slide closing (52 ms, Fig. 1a).
PEW Science Research Note 1: Performance note 4, above, is particularly unique. The pistol slide closing signatures with the Beretta 21A, when using the CAT SR, present with slightly higher amplitude than they would with a typical rimfire pistol silencer. This phenomenon is due to the extremely low mass of the silencer (the CAT SR test specimen weighs 2.8 ounces). When a silencer is attached to the Beretta 21A, it produces audible resonance in response to mechanical impact from slide cycling. The natural frequency of vibration of the weapon system, and silencer (resonator), is indirectly proportional to the system mass. One of the primary vibrational modes of this system is typically inherently damped above a certain mass threshold with, for example, a heavier rimfire silencer containing steel baffles. Removing mass from the silencer results in an increase in slide closing impact noise resonance. This undamped resonance presents as the peak transient at approximately 52 ms in each shot (Fig. 1a). The mass of the silencer is not sufficient to reduce the transient’s amplitude to the levels seen in the tests of the Rugged Oculus (6.2) or Resilient Suppressors Jessie’s Girl (6.136). The user may safely perform self-validation of this phenomenon, if desired. With the pistol unloaded, the user may pull back and release the slide of the Beretta 21A with each of the silencers attached. The mechanical signature produced by slide closing impact will be loudest with the CAT SR, compared with that from use of those heavier silencers. Other lightweight rimfire silencers produce similar phenomena on this host weapon.
It is interesting to note that although the low mass of the CAT SR results in louder mechanical action noise on this host, the overall signature is so significantly suppressed, that it is still less severe than the other silencers tested, in totality. In fact, the signature from muzzle blast is so suppressed by the CAT SR on this host that it is only of marginally higher amplitude than the slide closing signatures, themselves. PEW Science postulates that the performance of the CAT SR, on all tested platforms to date, is pushing the limits of muzzle-attached rimfire suppression technology, for the size envelope. PEW Science laboratory rimfire silencer testing is ongoing.
PEW Science Research Note 2: PEW Science previously evaluated the CAT SURGE BYPASS technology in several ammunition combustion regimes, including:
Supersonic 5.56x45mm NATO, with multiple barrel length semiautomatic rifles: CAT ODB 10.3-in MK18 (6.120), CAT WB 10.3-in MK18 (6.129), and CAT WB 14.5-in M4A1 (6.130).
Subsonic 300 BLK: CAT ODB 8-in bolt-action (6.122).
In the above evaluations, similar performance attributes to those noted above were observed with this hybrid technology, regardless of combustion amplitude and duration. When applying SURGE BYPASS hybrid technology to rimfire applications, high early time flow rate with late time gas momentum throttling remain the principal performance considerations. This differs from technologies such as Flow-Through from HUXWRX or Forward Flux from Sig Sauer, in which late time gas momentum may be higher than desirable if overall sound field suppression is a performance consideration. Research Supplement 6.124 examining the characteristics of different examples of silencer technologies, including hybrid designs, is available for reference.
The high early-time flow rate from the CAT SR does pay dividends in reducing ejection port blast hazard to the weapon operator with the Beretta 21A pistol. The signatures at the shooter’s ear are examined in detail in the Member Version of this article.
PEW Science Research Note 3: The rimfire silencer performance Rankings are now expanding; the CAT SR joins the Resilient Suppressor’s Jessie’s Girl and the Rugged Oculus (in two configurations) in the current published dataset. Again, users should note that performance of rimfire silencers on long and short barrels may be significantly different, even with subsonic ammunition, depending on silencer design. These performance differentials are the subject of ongoing PEW Science research.
6.141.1.2 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 shooter’s ear for all 6 shots are shown in Figure 3. The primary sound signature history is shown on the left. A zoomed-in timescale is displayed on the right, in the region of peak sound pressure. The real sound impulse (momentum transfer potential) histories at the ear from the same 6-shot test are shown in Figure 4. Full and short timescales are shown.
Figure 3a. CAT/SR/A1 Subsonic .22 LR Beretta 21A Subcompact Semiautomatic Pistol Ear Sound Pressure Signature
Figure 3b. CAT/SR/A1 Subsonic .22 LR Beretta 21A Subcompact Semiautomatic Pistol Ear Sound Pressure Signature, Short Time Window
Figure 4a. CAT/SR/A1 Subsonic .22 LR Beretta 21A Subcompact Semiautomatic Pistol Ear Sound Impulse Signature
Figure 4b. CAT/SR/A1 Subsonic .22 LR Beretta 21A Subcompact Semiautomatic Pistol Ear Sound Impulse Signature
Much of the same behavior measured at the muzzle of the system is displayed in the waveforms measured at the shooter’s ear with the CAT SR. The signatures are of significantly low amplitude. This is the case in pressure space (Figure 3) as well as in the examination of the blast impulse signatures (Figure 4).
PEW Science Research Note 4: Of interesting note, the lack of FRP that occurs at the muzzle remains in the sound field near the shooter’s head. The CAT SR produces no FRP on suppressed rimfire bolt-action rifle or semiautomatic subcompact pistol, neither at the muzzle, nor the shooter’s ear. For all intents and purposes, FRP is not a practical consideration with this silencer, in accordance with PEW Science laboratory testing, to date. However, PEW Science does acknowledge that there remain other combinations of rimfire host weapons and rimfire ammunition untested. Further rimfire testing is ongoing.
The Suppression Rating at the shooter’s ear with the CAT SR on this host weapon enters the 80-zone. For context, the user is encouraged to examine the Rankings Section of the Standard. To date, the only shooter’s ear signatures entering the 80-zone in the research pedigree are those from suppressed bolt-action rimfire rifle at the shooter’s ear. For a suppressed subcompact semiautomatic rimfire pistol to produce such a Suppression Rating is highly unusual. The next closest shooter’s ear Suppression Rating with this Beretta 21A host weapon is a category more severe on the scale.
PEW Science Research Note 5: In addition to significantly suppressed muzzle blast loads, the ejection port blast loads being less severe with the CAT SR contribute to the aforementioned high shooter’s ear Suppression Rating. The hybrid design of the silencer pays dividends in this regard. The oscillatory momentum displayed post-peak at approximately 32.8 ms (Figure 4) highlights how mechanical action noise, itself, is a large proportion of the overall signature. The blast loads are being suppressed to unusually low amplitudes.
6.141.2 Suppression Rating Comparison - Semiautomatic Subsonic .22 LR
The CAT/SR/A1 was developed to maximize pure sound signature reduction (PEW Science Suppression Rating) on both low and high pressure rimfire hosts (e.g. bolt-action rifle and semiautomatic pistol), regardless of barrel length or action type. Figure 6 shows a performance comparison of rimfire silencer configurations tested on a subcompact semiautomatic pistol shown in public PEW Science testing, to date. Suppression Ratings are shown for both the shooter and bystanders.
Figure 6. Suppression Rating Comparisons Of Rimfire Silencers Using PEW-SOFT subsonic .22 LR Beretta 21A Subcompact Semiautomatic Pistol Test Data
The performance of the CAT SR is extremely high. As discussed above, the signature from muzzle blast is so suppressed by the CAT SR on this host that it is only of marginally higher amplitude than the slide closing signatures, themselves. This phenomenon is reflected in the muzzle Suppression Rating, which is half a category higher than the nearest competitor in the current dataset.
At the shooter’s ear on the subcompact semiautomatic Beretta 21A pistol, the suppression performance of the CAT SR is unprecedented. The performance gap between the performance of the SR and the other tested silencer configurations is nontrivial; it is a category higher on the Suppression Rating scale. This superior suppression performance is a direct result of high performance muzzle blast suppression in tandem with high early-time flow rate nullifying the severity of ejection port blast loads from the semiautomatic pistol. The CAT SURGE BYPASS technology implementation in the SR results in the quietest overall suppressed rimfire pistol configuration tested by PEW Science, to date. With the addition of superior FRP performance, the CAT SR exhibits one of the highest signature suppression performance potentials of any silencer tested, in general.
From the above data, it can be concluded that the CAT SR and the short configuration of the Rugged Oculus, for example, produce signatures that have such contrasting severity that their nature may be interpreted as drastically different by weapon operators and bystanders. Even when reconfiguring the Rugged Oculus to the long configuration, its low-pressure optimized baffle geometry is unable to reach the performance of the CAT SR. The higher-pressure optimized Resilient Jessie’s Girl also fails to reach the gross suppression performance of the CAT SR, and its flow rate is lower; the higher back pressure of the Jessie’s Girl does not mitigate ejection port blast to the degree required to reach SR levels of pistol suppression.
The signature of a high performance rimfire silencer with subsonic ammunition fired from a semiautomatic pistol is significantly suppressed and may not sound like a “gunshot” to the operator or to bystanders. When such systems enter the 80-zone on the Suppression Rating scale on a reciprocating weapon, the signatures have a large proportion of audibly discernable mechanical noise. It is important for operators and bystanders to remain cognizant of the potential hazards of firearm use and the potential lethality of such weapon systems; the operation of such systems, if not in accordance with weapon and silencer manufacturer instructions, may still result in serious injury or death. The 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.
6.141.3 Review Summary: CAT/SR/A1 on a Beretta 21A Subcompact Semiautomatic Pistol
When paired with the Beretta 21A subcompact semiautomatic pistol and fired with CCI SV .22 LR ammunition, the CAT/SR/A1 achieved a composite Suppression Rating™ of 87.6 in PEW Science testing.
The bolt-action rifle rimfire performance of the CAT/SR/A1 is detailed in Sound Signature Review 6.140, in which it achieved a composite Suppression Rating of 96.8.
As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.
PEW Science Laboratory Staff Opinion:
The Combat Application Technologies CAT/SR/A1 is a rimfire silencer that exhibits enhanced performance characteristics on a variety of rimfire host weapons of varied barrel length, including semiautomatic pistols with subsonic ammunition. It is rated for 5.7x28mm, and weighs only 2.8 ounces, as tested. The silencer exhibits no discernable first round pop in the tested combustion regime. Other than the removable end cap, the silencer is sealed; its monolithic DMLS titanium body may be cleaned with a variety of chemical solutions, including those offered by CAT.
The CAT SR incorporates elements of CAT Surge Bypass technology in its design. When applying Surge Bypass hybrid technology to rimfire applications, high early time flow rate with late time gas momentum throttling remain the principal performance considerations. This differs from technologies such as Flow-Through from HUXWRX or Forward Flux from Sig Sauer, in which late time gas momentum may be higher than desirable if overall sound field suppression is a performance consideration. The high early-time flow rate from the CAT SR does pay dividends in reducing ejection port blast hazard to the weapon operator with the Beretta 21A pistol.
The CAT SR is extremely light weight. The test specimen evaluated by PEW Science weighs approximately 2.8 ounces. In addition to influencing system handling characteristics, the low mass of the silencer also influences the sound signature, directly, by changing the natural frequency of the primary vibrational mode of the total weapon system such that impulsive noise events from mechanical impact are subject to a lower degree of system damping. For example, pistol action noise from slide closing may sound different to the user with such a silencer installed on the weapon, compared with that from the use of a heavier silencer.
In totality, the CAT SR produces the least severe sound signature on rimfire host weapon platforms of any rimfire silencer tested by the PEW Science laboratory, to date. Its lack of perceptible FRP on this platform may be of significant importance to some users. The CAT SR exhibits one of the highest signature suppression performance potentials of any silencer tested, in general.
Servicing the CAT SR is accomplished by removing the silencer’s end cap and soaking with the user’s cleaning solution of choice to remove lead fouling. The user may choose to use the organic acid CAT 206 cleaning solution, formulated for titanium or Inconel parts. In general, the user is encouraged to contact the manufacturer for cleaning and servicing directives.
PEW Science has not evaluated the durability of the CAT/SR/A1, nor its performance on cartridges other than subsonic .22 LR. It is important for the user to contact the manufacturer to determine the suitability of firing schedules and use cases.
In this review, the CAT/SR/A1 performance metrics depend upon suppressing a subsonic rimfire cartridge on a subcompact semiautomatic rimfire pistol, which is a difficult task. While the sound signature of such systems can be suppressed to levels that may not sound like a “gunshot” to the operator or to bystanders, PEW Science encourages the reader to remain vigilant with regard to all subsonic rimfire cartridge suppression claims. It is important for operators and bystanders to remain cognizant of the potential hazards of firearm use and the potential lethality of such weapon systems; the operation of such systems, if not in accordance with weapon and silencer manufacturer instructions, may still result in serious injury or death.
The hazard potential of subsonic rimfire pistol 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.
