SSS.6.242 - Combat Application Technologies CAT/SP and the .45ACP 1911
/Combat Application Technologies CAT/SP on the 1911 Full-Size .45ACP Semiautomatic Pistol
The CAT/SP (“SP” in this report) is designed by Combat Application Technologies (CAT). It is a .45 caliber centerfire pistol silencer, intended to suppress the .45ACP cartridge from semiautomatic handguns. The SP is a modular silencer with a 1.48-inch primary diameter, and its long configuration is 8.53 inches in length. In its short configuration, the silencer is 6.66 inches in length. These lengths include the internal inertial-decoupling piston possessing .578-28tpi or 16x1mm LH or RH threading. Users should note that the CAT SP is compatible with its own pistons, as well as those from SilencerCo, Rugged Suppressors, and CGS Group. Performance and operability differentials will occur with varying the piston type from CAT or CGS pistons. The entirety of the two silencer body sections are DMLS (3D-printed) from a proprietary Titanium alloy; the rear and front end caps are constructed from machined titanium. The silencer is user-configurable, and with the piston and spring installed, weighs 11.7 ounces in the long configuration and 9.3 ounces in the short configuration, as tested. The SP can be obtained from Silencer Shop.
Silencer Hazard Maps:
The predicted personnel hazards generated by the tested weapon system in this report, in the free field, are shown in the below Silencer Hazard Maps for both the long and short configurations of the silencer. Click or tap the Maps to enlarge. Please reference Silencer Hazard Map Brief 8.1.39 for further details. The PEW-SOFT HD Blast Hazard Prediction Tool and Hazard Mapper is presented in Report 8.1.1.
CAT SP (Long Configuration) 1911 Free Field Hazard Map Produced by PEW-SOFT HD Blast Hazard Prediction Tool using PEW Science Test Data
CAT SP (Short Configuration) 1911 Free Field Hazard Map Produced by PEW-SOFT HD Blast Hazard Prediction Tool using PEW Science Test Data
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-CAT-139-001-25. Therefore, data pertaining to the CAT/SP in this Sound Signature Review is published with the express written permission of Combat Application Technologies
Other CAT “SB-SHOCK” Technology Testing:
The CAT SC in both long and short configurations was evaluated in Report 6.162 on a 9mm semiautomatic pistol.
Summary and Table of Contents
This Sound Signature Review contains test results and analysis using the CAT SP in both its long and short configurations on the standard 1911 .45ACP combat handgun with 5.5-in factory threaded barrel. Speer Lawman 230gr ammunition was used in the test. Unsuppressed combustion phenomena using the 1911 test host is presented in Report 6.227.
Section 6.242.1 contains Suppression Rating comparisons of the CAT SP with other .45ACP systems, including the AAC Ti-RANT 45, as well as the KAC and B&T silencers evaluated on the HK MK23 and HK USP45 Tactical.
Section 6.242.2 contains the CAT SP Long Configuration test results and analysis on the 1911.
Section 6.242.3 contains the CAT SP Short Configuration test results and analysis on the 1911.
Section 6.242.4 repeats the initial summary suppression performance comparisons with additional commentary.
Section 6.242.5 contains the review summary and PEW Science laboratory staff opinions.
Summary: When paired with the 1911 full-size semiautomatic pistol and fired with Speer Lawman 230gr ammunition, the CAT SP in its long configuration achieved a Suppression Rating™ of 53.8 in PEW Science testing. The short configuration of the CAT SP achieved a Suppression Rating of 43.4 with the same weapon and ammunition.
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.
6.242.1 CAT SP and Legacy System Performance Summary
This report continues examination of .45ACP combustion phenomenology and its suppression from the 1911 full-size combat handgun. Previously, the Rugged Obsidian 45 and AAC Ti-RANT 45 were evaluated on the 1911. Additionally, two other .45ACP combat handguns were evaluated; the HK MK23 and USP45 Tactical, both with the KAC MOD.MK23/USP developed for the SOCOM MK23 Offensive Handgun (OHG) program and the B&T Impulse-IIA SD Mk23 Rev. 03 designed to function on the same host weapons. The reader may examine the full research report on the KAC and B&T silencers here.
Unsuppressed and suppressed muzzle blast pressure histories were measured from all systems in the free field. Data reduction was performed to derive blast impulse histories as well as computations of the PEW Science Suppression Rating DRC metrics at the fielded pressure sensor locations in accordance with the Silencer Sound Standard and compatible with MIL-STD 1474E.
Suppression Rating calculations from all test data in the above research programs are summarized in Figure 1.
Fig 1. Suppression Rating Comparisons of the CAT SP, Rugged Obsidian 45, and AAC Ti-RANT 45 on the Remington 1911 R1 and KAC MOD.MK23/USP and B&T Impulse-IIA SD Mk23 Rev. 03 silencers on the HK MK23 and USP45 Tactical full-size semiautomatic pistols Using PEW-SOFT Test Data and PEW Science Analysis
From the above performance comparisons, the following gross conclusions can be made:
The long configuration of the CAT SP produces the highest pure muzzle suppression performance and operator suppression performance of the group. Its combination of high flow rate and the SB-SHOCK technology produce operator risk that is relatively low compared to other systems.
The Rugged Obsidian 45 produces the second highest pure muzzle suppression performance of the group, when used in its long configuration. However, its significant back pressure results in an operator (shooter’s ear) Suppression Rating almost a full category lower than that of the legacy AAC Ti-RANT 45, and on par with that of the legacy KAC silencer on the MK23 and USP. This is a significant performance conclusion, as the Rugged Obsidian 45 is considered a “modern” silencer.
The short configuration of the CAT SP produces pure muzzle suppression on par with that of the short configuration of the Rugged Obsidian 45 on the 1911 and similar to that of the legacy KAC silencer on the MK23. However, the high early-time flow rate (lower early-time back pressure) of the CAT SP being maintained in the short configuration reduces ejection port blast and produces operator protection that exceeds that of the short Obsidian 45 by a full Suppression Rating category on the 1911 and begins to approach that of the full size legacy Ti-RANT 45 on the 1911. This performance is significant.
As previously reported, the AAC Ti-RANT 45 produces exceptionally higher performance than both the KAC and B&T silencers and its operator protection is also significantly more robust than that of the Rugged Obsidian 45, regardless of Obsidian configuration. Notably, the pure suppression performance of the Ti-RANT 45 is only approximately a half Suppression Rating category lower than the CAT SP. The CAT SP is more advanced and somewhat shorter than the Ti-RANT 45, but the relative performance of the legacy silencer is notable nonetheless.
The KAC MOD.MK23/USP silencer, and its requisite inertial-decoupling piston assemblies, provide scalable signature suppression and personnel hazard reduction performance on the two HK combat handgun host weapons. The KAC system performance is more robust than the B&T system performance.
The 1911 and HK MK23 system signatures may be suppressed to a greater degree than the HK USP45 Tactical system signature. This is a function of the longer 1911 and MK23 barrels generating lower muzzle blast pressure input into the silencer(s), as well as system lock time mechanics and dynamics.
The 1911 system lock time and barrel rifling differs from the two HK systems. This changes unsuppressed and suppressed hazards by varying ejection port blast timing and muzzle blast precursor development. Nonetheless, unsuppressed blast loads from all three weapon systems are exceedingly hazardous to personnel in the near field. Silencer use is recommended not only to minimize operational signature, but to reduce damage to the unprotected human ear. Unsuppressed blast loads from the three weapon systems were presented and examined in Report 6.227.
Please note that extrapolating the performance of a silencer when suppressing a 1911 to that of the same silencer suppressing a USP or MK23 may produce erroneous results due to the mechanical differences highlighted in (7). In general, gross risk fields may scale in severity, but there are system optimization differences present that cause discrete hazard scaling to be nonlinear or even uncorrelated. This is particularly the case with system-specific silencers such as the legacy KAC model which has tuned inertial decoupling assemblies for the two HK pistols, as noted in (5). In addition to these cautions, it is important to note that piston design can significantly influence suppression performance. The user is therefore encouraged to field silencer manufacturer-recommended pistons for a given silencer and weapon system combination, when possible.
Detailed suppressed signature evaluations of the CAT SP suppressing the .45ACP Remington 1911 R1 follow.
6.242.2 CAT SP (Long Configuration) 1911 Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the CAT SP in its long configuration tested on the Remington 1911 R1 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 SP (Long Configuration) Subsonic .45 ACP 1911 Sound Metric Summary
6.242.2.1 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, and the slide locked back on the slide-release lever actuated by 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 dataset. The waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science testing is 1.0 MS/s (1 MHz). The peaks, shape, and time phasing (when the peaks occur in relation to absolute time and to each other) of these raw waveforms are the most accurate of any firearm silencer testing publicly available. PEW-SOFT data is acquired by PEW Science independent testing; the industry leader in silencer sound research. For more information, please consult the Silencer Sound Standard.
The primary sound signature pressure histories for all 6 shots with the CAT SP in its long configuration tested on the Remington 1911 R1 are shown in Figure 2a. The sound signatures of Shot 1 and Shot 2 are shown in Figure 2b, in early time. The real sound impulse (momentum transfer potential) histories from the same 6-shot test are shown in Figure 3a. In Figure 3b, a shorter timescale is shown comparing the impulse of Shots 1 through 3.
Fig 2a. CAT SP (Long Configuration) Subsonic .45 ACP 1911 Semiautomatic Pistol Muzzle Sound Pressure Signature
Fig 2b. CAT SP (Long Configuration) Subsonic .45 ACP 1911 Semiautomatic Pistol Sound Pressure Signature
Figure 3a. CAT SP (Long Configuration) Subsonic .45 ACP 1911 Semiautomatic Pistol Muzzle Sound Impulse Signature
Figure 3b. CAT SP (Long Configuration) Subsonic .45 ACP 1911 Semiautomatic Pistol Muzzle Sound Impulse Signature
The .45 ACP cartridge is of significantly larger diameter than the commonly fielded 9x19mm cartridge, and it also operates at a lower combustion pressure. This creates complexities in balancing distal flow rate with adequate turbulence generation and heat transfer. The larger the silencer exit aperture, the more difficult the signature suppression, all other things equal. When combustion pressure drops, some silencer technologies lose suppression efficiency to a greater degree than do others. Conversely, some silencer technologies are shown to produce significantly higher efficiency than others.
The previous 9mm pistol suppression evaluation of the CAT SC (6.162) demonstrated how the CAT SB-SHOCK technology (a specific adaptation combining elements of SURGE BYPASS with DiVerge technologies for centerfire handgun use) was optimized for the lower combustion pressures of centerfire pistol cartridges. In theory, such a technology should provide scalable performance when suppressing .45ACP, despite the aforementioned challenges of a larger bore and lower input pressure. Based on the raw blast overpressure and impulse data measured in this test program, the SB-SHOCK implementation in the CAT SP appears to demonstrate that performance scaling. Specific observations are as follows:
Unusually low blast overpressure amplitude through the time regime of the complete gunshot (Fig. 2a).
Early and defined initial coupled jetting that is higher in relative amplitude than typical, but with truncated duration (Fig. 2b).
Extremely short duration primary jetting (Fig. 2b) that results in stable accumulation of peak momentum (Fig. 3a).
Minor first-round-pop (FRP) divergence that is confined to the short duration events in (2) and (3).
Very low overall blast impulse accumulation amplitude which is relatively consistent (Fig. 3).
PEW Science Research Note 1: Observations (1) and (5) are particularly unusual given observation (2). Typically when there is high relative initial coupled jetting, somewhat severe or high amplitude jetting will continue in early time. But in the case of the CAT SP, continued jetting is highly controlled. This control is extreme from the long configuration of the silencer and still present in the short configuration of the silencer, but to a lesser degree, which suggests it is a function of both the silencer’s early- and late-time flow rates (the phenomenon is not resulting from only “baffle count,” for example). That hypothesis is further supported by observation (3) occurring in both configurations, as well. Observation (4) is very notable given the large bore of the silencer and illustrates a true scalability of the SB-SHOCK technology as previously shown in the 9mm evaluation of the CAT SC.
PEW Science Research Note 2: The above performance factors, alone, are objectively significant. However, there is a combined performance factor that is equally if not more significant in that the early-time flow rate of the silencer is high enough and its distal momentum control is high enough in the long configuration such that the system back pressure is extremely low without undue influence to global signature suppression. This means that the hazard field is globally less severe than the other .45ACP silencers evaluated, to date, on a standard combat handgun. One can visualize the predicted global severity differentials using the Hazard Maps presented at the beginning of this report and in Silencer Hazard Map Brief 8.1.39.
PEW Science Research Note 3: It is very important to highlight that the legacy AAC Ti-RANT 45 (6.227), which is no longer in production, does approach the gross suppression performance of the long configuration of the CAT SP on the standard full-size 1911 .45ACP combat handgun. Furthermore, the Ti-RANT 45 is extremely competitive with the CAT SP, in pure suppression performance, on other .45ACP combat handguns as well. The legacy AAC optimized K-baffle geometry, in combination with its dual-layer annular porting array in the proximal section of the silencer, produces significantly advanced blast dynamics that were “ahead of their time” circa 2010 when the silencer debuted. The CAT SP is lighter and nominally shorter and does outperform the Ti-RANT 45, but the pure signature suppression performance differential is not as extreme as it is between the previously mentioned CAT SC and the AAC Ti-RANT 9 series (6.118) in the 9x19mm combustion regime.
The above performance comparisons highlight both the difficulty of .45ACP pistol suppression and advancements in the pistol suppression state of practice. As discussed in previous research, the “newness” or “modern nature” of a silencer may not be a good predictor of suppression performance. This was demonstrated in the evaluation of the highly prolific Rugged Obsidian 45 on the 1911 (6.234). In all PEW Science Laboratory internal research (IR) testing, the Obsidian 45 produces significantly more intense ejection port blast loads than the Ti-RANT 45 and now as presented, than the CAT SP. PEW Science IR testing has been conducted with various full size semiautomatic .45ACP handguns, including the HK MK23, USP45 Tactical, FN FNX-45 Tactical, Remington 1911 R1, and others. IR results demonstrate pervasive ejection port blast hazards with the Obsidian 45 in both the long and short configurations, regardless of test host weapon. Note that only full power subsonic .45ACP ammunition is used in PEW Science testing. It is possible that reduced power ammunition loads reduce ejection port blast hazards, but the relative nature of these performance conclusions should hold, regardless. The only reason the back pressure of the Obsidian 45 doesn’t overwhelm operator risk on a 9mm combat handgun is due to significant over bore for the cartridge. This phenomenon was explored in the Obsidian 9 test report. Back pressure still played a role, and further 9mm pistol silencer evaluations of the aforementioned CAT SC and the Dead Air Mojave 9 (6.177) again proved that late time back pressure reduction from over bore, alone, is unable to compensate for high early time back pressure when suppressing semiautomatic handguns. PEW Science research definitively concluded that early time flow rate is of paramount importance for operator blast overpressure risk reduction on reciprocating small arm weapon systems. That conclusion is, once again, supported by the behavior of the CAT SP in this report.
PEW Science Research Note 4: On closed-breech weapons, or weapons in which the chamber may be closed or extraction delayed by a relatively significant amount of time, high silencer flow rate is of less significance. However, almost all modern combat handguns using a modified Browning tilting-barrel action exhibit lock times unfavorable to significant backpressure generation. The 1911 uses a linked tilting barrel with less angular displacement and exhibits reduced ejection port blast hazards when suppressed, as a result. It is important to note that back pressure in a silencer design is not blowback. Back pressure is caused by blast load impulse accumulation above given thresholds in various parts of the silencer, and therefore occurs in multiple time regimes. Blast load impulse accumulation is the result of not only pressure stagnation, but additive load reflections. Without clearing (venting), impulse will continue to accumulate during the time regimes of interest. Matching the time regime of clearing to the requisite weapon function sequence is paramount to the design process used by suppressed small arm weapon system developers (developers of the whole systems; silencers and hosts). The back pressure generated by the CAT SP silencer on this weapon system is lower than that generated by many other designs (both legacy and modern).
PEW Science Research Note 5: As in most semiautomatic 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 80 ms in Figure 2a) the mechanical noise of the slide closing is observed. The pressure signature of Shot 6 does not display this event due to the slide remaining locked to the rear after the sixth and final round is fired from the magazine.
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 relatively 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 semiautomatic firearm configuration.
PEW Science Research Note 6: Note that the muzzle Suppression Rating of the CAT SP in its long configuration on the 1911 semiautomatic handgun test host is 52.1 and the shooter’s-ear Suppression Rating is 47.8; which are in different zones on the Suppression Rating Dose Chart. The gross suppression of a silencer, as well as its flow rate, influences the holistic signature on a semiautomatic host weapon. The reader is encouraged to consult the Hazard Maps at the beginning of this report and in Silencer Hazard Map Brief 8.1.39 to view personnel risk spatially. The signatures measured at the shooter’s ear with the long configuration of the silencer are presented and examined below.
6.242.2.2 SOUND SIGNATURES AT SHOOTER’S EAR
Real sound pressure histories from the same 6-shot test of the CAT SP in its long configuration on the Remington 1911 R1 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 4. The primary sound signature history is shown in Figure 4a. A zoomed-in timescale is displayed in Figure 4b, in the region of peak sound pressure for Shot 1, Shot 2, and Shot 3. The real sound impulse (momentum transfer potential) histories at the ear from the same 6-shot test are shown in Figure 5. Again, full and short timescales are shown.
Figure 4a. CAT SP (Long Configuration) Subsonic .45 ACP 1911 Semiautomatic Pistol Ear Sound Pressure Signature
Figure 4b. CAT SP (Long Configuration) Subsonic .45 ACP 1911 Semiautomatic Pistol Ear Sound Pressure Signature, Short Time Window
Figure 5a. CAT SP (Long Configuration) Subsonic .45 ACP 1911 Semiautomatic Pistol Ear Sound Impulse Signature
Figure 5b. CAT SP (Long Configuration) Subsonic .45 ACP 1911 Semiautomatic Pistol Ear Sound Impulse Signature Peaks
The signatures generated by the long configuration of the CAT SP on the 1911 are extremely different than those generated by the other silencers evaluated to date, including those generated by the AAC Ti-RANT 45 and the long Rugged Obsidian 45. The two gross differences are:
The peak amplitude of both blast overpressure and blast impulse from the systems differs. Though the Ti-RANT 45 positive phase impulse accumulation is only somewhat higher than that of the CAT SP, the overpressure is higher and the timing of when that overpressure is produced differs greatly.
The blast overpressure and impulse accumulation from the CAT SP is completely front-loaded. Ejection port blast contributions are reduced in amplitudes comparable to dynamic pistol action mechanical events. The reader may compare the positively increasing pressure ramp in Figure 6a of the Ti-RANT 45 and Obsidian 45 reports to that of the negatively decreasing pressure ramp in Figure 4a, above. Ejection port blast begins to dominate the signatures when using the Obsidian 45 and Ti-RANT 45.
Accordingly with (2), the impulse accumulation resulting from mechanical shock (~35 ms, Fig. 5b) is also reduced. This behavior is, again, much different than observed with the other two silencers.
Other than in early time, the consistency of the signature, from shot to shot, is high. FRP divergence during primary blast is minimal to non-existent.
The short configuration of the CAT SP is evaluated below on the same weapon system with the same ammunition.
6.242.3 CAT SP (Short Configuration) 1911 Test Results
A summary of the principal Silencer Sound Standard performance metrics of the CAT SP in its short configuration tested on the Remington 1911 R1 is shown in Table 2. 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 2. CAT SP (Short Configuration) Subsonic .45 ACP 1911 Sound Metric Summary
6.242.3.1 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, and the slide locked back on the slide-release lever actuated by 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 dataset. The waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science testing is 1.0 MS/s (1 MHz). The peaks, shape, and time phasing (when the peaks occur in relation to absolute time and to each other) of these raw waveforms are the most accurate of any firearm silencer testing publicly available. PEW-SOFT data is acquired by PEW Science independent testing; the industry leader in silencer sound research. For more information, please consult the Silencer Sound Standard.
The primary sound signature pressure histories for all 6 shots with the CAT SP in its short configuration tested on the Remington 1911 R1 are shown in Figure 6a. The sound signatures of Shot 1 and Shot 2 are shown in Figure 6b, in early time. The real sound impulse (momentum transfer potential) histories from the same 6-shot test are shown in Figure 7a. In Figure 7b, a shorter timescale is shown comparing the impulse of Shots 1 through 3.
Fig 6a. CAT SP (Short Configuration) Subsonic .45 ACP 1911 Semiautomatic Pistol Muzzle Sound Pressure Signature
Fig 6b. CAT SP (Short Configuration) Subsonic .45 ACP 1911 Semiautomatic Pistol Muzzle Sound Pressure Signature, Short Time Window
Fig 7a. CAT SP (Short Configuration) Subsonic .45 ACP 1911 Semiautomatic Pistol Muzzle Sound Impulse Signature
Fig 7b. CAT SP (Short Configuration) Subsonic .45 ACP 1911 Semiautomatic Pistol Muzzle Sound Impulse Signature, Short Time Window
The CAT SP is a modular silencer in that the front section can be removed. This reduces the total baffle count to 12, from the original 16. The proximal end of the silencer, and thus the early time flow rate, remains identical in both configurations. However, the late time flow rate increases significantly when the front section is removed. This behavior is quantified directly by the calculated drop in the Omega Metric, derived from the rate of impulse accumulation in Figure 7a compared with that in Figure 3a. Blast momentum escaping from the silencer occurs faster when in the short configuration, compared with that of the long configuration. This is typical of modular silencers, in general. The above raw test data shows:
Higher amplitude muzzle blast with faster blowdown (Fig. 6a).
Higher amplitude coupled jetting (Fig. 6b).
Similar though earlier jet throttle (Fig. 6b), in accordance with (1).
Consistent momentum accumulation, starting with FRP (Fig. 7a).
Observations (1) and (2) are expected, whereas (3) occurs earlier than typical. Observation (4) is unusual and demonstrates that FRP masking is maintained in the short configuration.
PEW Science Research Note 7: The difference between the short configuration of the CAT SP and the short configuration of the Rugged Obsidian 45, for example, is that the early-time flow rate in the CAT SP is very high. Although late-time back pressure is reduced in both silencers when converting them to their short configurations, the early-time back pressure is not changeable; it is inherent to the primary section of the silencer. This performance difference, along with the more efficient (and numerous) baffle technology in the SP produces superior hazard reduction to the Rugged silencer. This is reflected in the calculated operator (shooter’s ear) Suppression Ratings, where that of the short CAT SP is a category higher than that of the short Rugged Obsidian 45.
PEW Science Research Note 8: As described above, the back pressure of the CAT SP in its short configuration is identical to the long configuration in early time, but lower in late time. The ejection port blast from the weapon system is already significantly reduced compared to typical pistol silencers with the CAT SP and even further reduced in the short configuration. However, because of the degree of increased muzzle blast severity and muzzle blast propagation to the operator’s location, the net operator protection drops. This phenomenon is visually presented in the accompanying Silencer Hazard Maps at the beginning of this report and in Silencer Hazard Map Brief 8.1.39.
PEW Science Research Note 9: The muzzle Suppression Rating of the CAT SP, in the free field, changes from 52.1 to 33.0 when changing from its long to short configuration. This performance change, spanning almost two full Suppression Rating Performance Categories, indicates that the hazard adjacent to the weapon system when the two different configurations of the silencer are used is significantly different. However, the operator hazard reduction with the short configuration of the CAT SP does not drop as significantly. This is due to the aforementioned back pressure reduction and hazard field shape differences. It is extremely important to note that the shooter’s ear Suppression Rating is calculated from free field blast overpressure data adjacent to the operator’s head. Environmental changes and deviations from free field conditions can, and most likely will, result in protection differentials that shift. Severe environmental differentials may provide severity with highly nonlinear characteristics and outcomes. PEW Science strongly encourages examination of these performance factors in Section 6.242.3.2, below.
6.242.3.2 SOUND SIGNATURES AT SHOOTER’S EAR
Real sound pressure histories from the same 6-shot test of the CAT SP in its short configuration on the Remington 1911 R1 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 8. The primary sound signature history is shown in Figure 8a. A zoomed-in timescale is displayed in Figure 8b, in the region of peak sound pressure for Shot 1, Shot 2, and Shot 3. The real sound impulse (momentum transfer potential) histories at the ear from the same 6-shot test are shown in Figure 9. Again, full and short timescales are shown.
Fig 8a. CAT SP (Short Configuration) Subsonic .45 ACP 1911 Semiautomatic Pistol Ear Sound Pressure Signature
Fig 8b. CAT SP (Short Configuration) Subsonic .45 ACP 1911 Semiautomatic Pistol Ear Sound Pressure Signature, Short Time Window
Fig 9a. CAT SP (Short Configuration) Subsonic .45 ACP 1911 Semiautomatic Pistol Ear Sound Impulse Signature
Fig 9b. CAT SP (Short Configuration) Subsonic .45 ACP 1911 Semiautomatic Pistol Ear Sound Impulse Signature, Short Time Window
As was the case with the long configuration of the CAT SP, the signatures from the short configuration of the silencer are significantly different than the other silencers evaluated on the 1911 pistol, to date. A similar negatively decreasing pressure ramp is observed as was observed in Section 6.242.2.2. Reductions in peak pressure, momentum, and mechanical shock are also observed.
Notably, consistency in blast propagation remains. This consistency occurs throughout primary accumulation, blowdown, and into mechanical noise as the slide, piston, and silencer assembly impact each other. It is likely, though not confirmed, that the dynamics of the weapon system are operating closer to the unsuppressed state than with a higher back pressure silencer like the Obsidian, for example.
PEW Science Research Note 10: An interesting phenomenon produced by the short configuration of the CAT SP is a relatively sharp accumulation of impulse at approximately 31.5 ms. Also unusual is how fast this impulse decays. This behavior, along with the nesting of ejection port blast in higher back pressure silencers (long Obsidian 45) and decoupling in low(er) back pressure silencers (short Obsidian 45 and full size Ti-RANT 45) is a subject of continued research.
PEW Science Research Note 11: As discussed in the preceding section of this report, the Suppression Rating at the shooter’s ear, on a centerfire pistol, when you change a silencer from its “long” configuration to its “short” configuration, may not appreciably change or at least not change as much as the Suppression Rating adjacent to the muzzle. However, when it does change, it is important to understand that the acute hazard to the operator is changing, and not necessarily the gross sound field overall “loudness.” The CAT SP in its short configuration is likely considered “louder” than in its long configuration, but that is not only due to the increase in acute hazard to the operator (lower shooter’s ear Suppression Rating), it is also due to the gross decrease in muzzle Suppression Rating. The detailed Suppression Ratings (muzzle and ear) quantify hearing damage risk to adjacent bystanders and the shooter, in the free field.
It is very important to note that what you, as a human, hear is a function of every pressure source propagating through the atmosphere that reaches your pressure sensors (your ears). In early time, the risk to your ear is highest. In late time, after the primary combustion events have vented, there are signature components that may propagate downrange, adjacent to your location, and even back toward you upon reflecting from objects such as tree lines, automobiles, or structures. Those late time signature components can give a subjective impression to the operator that may induce a perception of “loudness.” Loudness, as defined in the Silencer Sound Standard however, is objective hearing damage risk potential.
Factors that may increase the actual objective loudness (the risk to you, the operator) of using a system with a lower muzzle Suppression Rating despite the same or higher shooter’s ear Suppression Rating include shooting the suppressed weapon system:
Indoors.
In a vehicle.
Next to a building, berm, or tree line.
This is the same phenomenon that presents when shooting a high flow rate centerfire rifle silencer on a reciprocating semiautomatic or automatic rifle. Reference the test report of the HUXWRX FLOW 556K (6.83) and FLOW 762 Ti (6.114). Even if not indoors or adjacent to reflecting surfaces, late time signatures propagated from lower muzzle suppression rating systems will influence shooter perception in late time. This does not influence the shooter’s ear Suppression Rating because it does not increase the hearing damage risk potential to the shooter in the free field.
6.242.4 Suppression Rating Comparisons (Subsonic .45 ACP from the 1911, HK MK23, and USP 45 Tactical)
Figure 10 again presents a comparison of the calculated PEW Science Suppression Ratings of the CAT SP in both its long and short configurations and the Rugged Obsidian 45 in both of its configurations along with the AAC Ti-RANT 45 on the full-size .45ACP 1911, along with the KAC MOD.MK23/USP and B&T Impulse-IIA SD Mk23 Rev. 03 silencers on both full-size HK MK23 and USP45 Tactical using full power subsonic Speer Lawman 230gr .45 ACP ammunition. Unsuppressed system risk metrics are also presented.
Fig 10. Suppression Rating Comparisons of CAT SP, Rugged Obsidian 45, and AAC Ti-RANT 45 on the Remington 1911 R1 and KAC MOD.MK23/USP and B&T Impulse-IIA SD Mk23 Rev. 03 silencers on the HK MK23 and USP45 Tactical full-size semiautomatic pistols Using PEW-SOFT Test Data and PEW Science Analysis
From the above performance comparisons, the following gross conclusions can be made:
The long configuration of the CAT SP produces the highest pure muzzle suppression performance and operator suppression performance of the group. Its combination of high flow rate and the SB-SHOCK technology produce operator risk that is relatively low compared to other systems.
The Rugged Obsidian 45 produces the second highest pure muzzle suppression performance of the group, when used in its long configuration. However, its significant back pressure results in an operator (shooter’s ear) Suppression Rating almost a full category lower than that of the legacy AAC Ti-RANT 45, and on par with that of the legacy KAC silencer on the MK23 and USP. This is a significant performance conclusion, as the Rugged Obsidian 45 is considered a “modern” silencer.
The short configuration of the CAT SP produces pure muzzle suppression on par with that of the short configuration of the Rugged Obsidian 45 on the 1911 and similar to that of the legacy KAC silencer on the MK23. However, the high early-time flow rate (lower early-time back pressure) of the CAT SP being maintained in the short configuration reduces ejection port blast and produces operator protection that exceeds that of the short Obsidian 45 by a full Suppression Rating category on the 1911 and begins to approach that of the full size legacy Ti-RANT 45 on the 1911. This performance is significant.
As previously reported, the AAC Ti-RANT 45 produces exceptionally higher performance than both the KAC and B&T silencers and its operator protection is also significantly more robust than that of the Rugged Obsidian 45, regardless of Obsidian configuration. Notably, the pure suppression performance of the Ti-RANT 45 is only approximately a half Suppression Rating category lower than the CAT SP. The CAT SP is more advanced and somewhat shorter than the Ti-RANT 45, but the relative performance of the legacy silencer is notable nonetheless.
The KAC MOD.MK23/USP silencer, and its requisite inertial-decoupling piston assemblies, provide scalable signature suppression and personnel hazard reduction performance on the two HK combat handgun host weapons. The KAC system performance is more robust than the B&T system performance.
The 1911 and HK MK23 system signatures may be suppressed to a greater degree than the HK USP45 Tactical system signature. This is a function of the longer 1911 and MK23 barrels generating lower muzzle blast pressure input into the silencer(s), as well as system lock time mechanics and dynamics.
The 1911 system lock time and barrel rifling differs from the two HK systems. This changes unsuppressed and suppressed hazards by varying ejection port blast timing and muzzle blast precursor development. Nonetheless, unsuppressed blast loads from all three weapon systems are exceedingly hazardous to personnel in the near field. Silencer use is recommended not only to minimize operational signature, but to reduce damage to the unprotected human ear. Unsuppressed blast loads from the three weapon systems were presented and examined in Report 6.227.
Please note that extrapolating the performance of a silencer when suppressing a 1911 to that of the same silencer suppressing a USP or MK23 may produce erroneous results due to the mechanical differences highlighted in (7). In general, gross risk fields may scale in severity, but there are system optimization differences present that cause discrete hazard scaling to be nonlinear or even uncorrelated. This is particularly the case with system-specific silencers such as the legacy KAC model which has tuned inertial decoupling assemblies for the two HK pistols, as noted in (5). In addition to these cautions, it is important to note that piston design can significantly influence suppression performance. The user is therefore encouraged to field silencer manufacturer-recommended pistons for a given silencer and weapon system combination, when possible.
PEW Science Research Note 12: 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 with a lower Suppression Rating are postulated to be more hazardous to the unprotected ear than silencers with a higher Suppression Rating. To iterate, the Suppression Rating is a DRC - it is not a subjective quantity; it is an objective quantification of hearing damage risk potential.
The signature to which the shooter’s ear is subjected is a function of both ejection port blast and muzzle blast. When the silencer’s endcap is in closer proximity to the shooter, the severity is increased. The coalescing of the ejection port blast overpressure with the primary muzzle blast exacerbates the severity of the signature at the shooter’s head position. It is not ejection port signature, alone, that dictates the signature measured at the shooter’s head position.
6.242.5 Review Summary: CAT SP on the 1911 Full-Size .45ACP Semiautomatic Pistol
When paired with the 1911 full-size semiautomatic pistol and fired with Speer Lawman 230gr ammunition, the CAT SP in its long configuration achieved a Suppression Rating™ of 53.8 in PEW Science testing. The short configuration of the CAT SP achieved a Suppression Rating of 43.4 with the same weapon and ammunition.
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/SP (CAT SP) is a full size modular .45 caliber pistol silencer that exhibits relatively high sound signature suppression performance for both operators and bystanders. The silencer is intended for use on semiautomatic combat handguns chambered in .45 ACP and its combined performance, flow rate, and modularity represent a relatively significant advancement in centerfire .45 ACP pistol suppression. Eclipsing the performance of the venerable and historic AAC Ti-RANT 45, the CAT SP is lighter, nominally shorter, and has extremely low early-time back pressure. The .45 caliber CAT SP uses an adaptation of the same CAT SB-SHOCK technology implemented in the 9mm CAT SC to mask first round pop in both its long and short configurations.
The previous 9mm pistol suppression evaluation of the CAT SC demonstrated how the CAT SB-SHOCK technology (a specific adaptation combining elements of SURGE BYPASS with DiVerge technologies for centerfire handgun use) was optimized for the lower combustion pressures of centerfire pistol cartridges. In theory, such a technology should provide scalable performance when suppressing .45ACP, despite the challenges of a larger bore and lower input pressure. Based on the raw blast overpressure and impulse data measured in this test program, the SB-SHOCK implementation in the CAT SP appears to demonstrate that performance scaling.
The long configuration of the CAT SP produces the highest pure muzzle suppression performance and operator suppression performance on a .45 caliber combat handgun in the research, to date. Its combination of high flow rate and pure suppression produce operator risk that is relatively low compared to other systems. The short configuration of the CAT SP produces pure muzzle suppression on par with that of the short configuration of the Rugged Obsidian 45 on the 1911 and similar to that of the legacy KAC silencer on the MK23. However, the high early-time flow rate (lower early-time back pressure) of the CAT SP being maintained in the short configuration reduces ejection port blast and produces operator protection that exceeds that of the short Obsidian 45 by a full Suppression Rating category on the 1911 and begins to approach that of the full size legacy Ti-RANT 45 on the 1911. This performance is significant.
The difference between the short configuration of the CAT SP and the short configuration of the Rugged Obsidian 45, for example, is that the early-time flow rate in the CAT SP is very high. Although late-time back pressure is reduced in both silencers when converting them to their short configurations, the early-time back pressure is not changeable; it is inherent to the primary section of the silencer. This performance difference, along with the more efficient (and numerous) baffle technology in the SP produces superior hazard reduction to the Rugged silencer. This is reflected in the calculated operator (shooter’s ear) Suppression Ratings, where that of the short CAT SP is a category higher than that of the short Rugged Obsidian 45.
The CAT SP may be used with CAT, CGS, SilencerCo, and Rugged pistons, though performance with SilencerCo and Rugged pistons may be reduced. The CAT SP end cap and rear cap may be removed with a wrench by the user; wrench flats are present on both components. The distal section of the silencer may be removed and installed into the primary proximal section by hand. No tools are needed for this disassembly; a tapered interface facilitates rotational retention with hand-snug torque values.
The CAT SP is not intended for submachinegun use. Use on such systems, even if demonstrating high suppression performance, may be suboptimal. PEW Science encourages the user to contact the manufacturer for guidance on silencer use case, firing schedule, maintenance, and other ownership guidance.
In this review, the CAT SP performance metrics depend upon suppressing the venerable and historic full-size 1911 combat handgun firing the full-power .45ACP subsonic centerfire pistol cartridge. PEW Science encourages the reader to carefully consider action dynamics, barrel lengths, and other characteristics in the selection of centerfire pistol silencer hosts.
The hearing damage potential of centerfire pistol 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. Note that the presence of nearby reflecting surfaces, as well as ammunition choice, can influence the sound signature to which both the shooter and bystanders are subjected.
