SSS.6.46 - Surefire SOCOM762-RC2 and the Q mini FIX 300 BLK Subsonic (Free Version)
/Surefire SOCOM762-RC2 on a Q mini FIX 300 BLK with 8-in Barrel
The SOCOM762-RC2 is manufactured by Surefire. It is a 30 caliber centerfire rifle silencer, intended to suppress many cartridges with projectiles appropriately sized to travel through the bore, up to and including .300 Winchester Magnum. It has a 1.5-inch diameter and is 8.4 inches in length. The silencer mounts to the host firearm with a proprietary mounting system; the user may choose from various Surefire flash hider and muzzle brake mounts. The outer tube and end-cap are constructed of heat treated stainless steel. The baffles are constructed of Inconel steel alloy. As tested, the silencer weighs 20.7 ounces and the 3-prong flash hider weighs 4 ounces, for a total system weight of 24.7 ounces. The SOCOM762-RC2 can be obtained from Silencer Shop.
This review contains single-test results using the SOCOM762-RC2 mounted with the SOCOM 3-Prong flash hider mount on the Q mini FIX bolt action pistol, chambered in 300 BLK with an 8-inch barrel. Discreet Ballistics 190gr ammunition was used in the test.
- Section 6.46.1 contains the SOCOM762-RC2 test results and analysis.
- Section 6.46.2 contains Suppression Rating comparisons with selected .30 rifle silencers in the subsonic flow regime.
- Section 6.46.3 contains Suppression Rating comparisons with selected .30 rifle silencers in both the subsonic and supersonic flow regimes, along with high-fidelity comparisons of the SOCOM762-RC2 performance in both flow regimes in pressure and impulse space. PEW Science Back Pressure Metric, Ω [Pa-1] comparisons are also included. Further information about the Ω metric and Omega Zones can be obtained in PEW Science Research Supplement 6.40 (Public Article).
- Section 6.46.4 contains the review summary and PEW Science opinions.
Summary: When paired with the Q mini FIX 8” 300 BLK and fired with Discreet Ballistics 190gr Subsonic Target ammunition, the Surefire SOCOM762-RC2 with the SOCOM 3-Prong flash hider achieved a Suppression Rating™ of 44.0 in PEW Science testing.
The supersonic .308 performance of the Surefire SOCOM762-RC2 is detailed in previous Sound Signature Review 6.26, in which it achieved a Suppression Rating of 38.4.
Relative Suppression Rating Performance is Summarized in SSS.7 - PEW Science Rankings
6.46.1 Surefire SOCOM762-RC2 Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Surefire SOCOM762-RC2 is shown in Table 1. The data acquired 1.0 m (39.4 in) left of the muzzle is available for viewing to all. The data acquired 0.15 m (6 in) right of the shooter’s ear is only available to membership supporters of PEW Science and the Silencer Sound Standard. You can support PEW Science testing, research, and development with a membership, here. State-of-the-art firearm sound signature testing and research conducted by PEW Science is supported by readers like you.
Table 1. Surefire SOCOM762-RC2 (SOCOM 3-Prong Flash Hider) Sound Metric Summary
6.46.1.1 SOUND SIGNATURES AT THE MUZZLE
Real sound pressure histories from a 5-shot test acquired with PEW-SOFT™ are shown below. The waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science 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, here.
Figure 1 shows a 2-millisecond long sequence of events during the first test shot with the Surefire SOCOM762-RC2, as measured 1.0 m left of the muzzle. There are three significant events shown:
During combustion within the weapon system, a 121.5 dB peak is measured.
Precursor flow is suppressed until bullet exit where the peak amplitude of the coupled events is measured to be 140.0 dB.
The maximum pressure amplitude of the first shot, the primary muzzle blast flow, is measured to be 148.7 dB.
This is a typical sequence observed when firing subsonic 300 BLK ammunition from a bolt-action weapon system with an attached silencer that exhibits low flow restriction (low back pressure); internal silencer design can significantly influence the measured timing and pressure amplitudes. Supersonic and subsonic suppression performance, along with back pressure comparisons are shown in Section 6.46.3 of this review, with the PEW Science Back Pressure Metric, Ω [Pa-1].
Fig. 1 Early-Time Shot History, Surefire SOCOM762-RC2 (SOCOM 3-Prong Flash Hider) Bolt Action 300 BLK Muzzle Sound Pressure Signature, 24-OCT-2020
The back pressure generated by the Surefire SOCOM762-RC2 is relatively low, but not as low as the OSS HX-QD 762 silencer examined in the previous review. During subsonic 300 BLK suppression with the OSS silencer, precursor flow (the pressure measured from compression and subsequent overpressure pulse through the air column in the gun barrel by the bullet prior to bullet exit) was visible and plainly decoupled from the bullet exit event. The SOCOM762-RC2, however, is able to suppress the precursor flow such that its occurrence is coupled with the bullet’s endcap exit, as shown in event (2) in Figure 1. This subtle distinction between the waveforms emitted from the two silencers highlights the vastly different suppression mechanisms employed by the two silencers. While both silencers achieve similar supersonic suppression performance, the Surefire SOCOM762-RC2 is able to outperform the OSS silencer in subsonic suppression, while still offering users reduced back pressure; it traps enough gas with conventional baffle geometry while venting through the stack to reduce back pressure. Quantitative performance comparisons are provided in Section 6.46.3 of this review. Note that the SOCOM762-RC2 is not intended to be a specialized 300 BLK silencer; Surefire produces a specialized model (the SOCOM300 SPS) for this use. PEW Science has performed initial evaluation of the SOCOM300 SPS and further testing is planned.
The primary sound signature pressure histories for all 5 shots are shown in Figure 2a. A zoomed-in timescale displays the region of peak sound pressure in Figure 2b, for the first three shots. The real sound impulse (momentum transfer potential) histories from the same 5-shot test are shown in Figure 3. Again, full and short timescales are shown.
Fig 2a. Surefire SOCOM762-RC2 (SOCOM 3-Prong Flash Hider) Bolt Action 300 BLK Muzzle Sound Pressure Signature, 24-OCT-2020
Fig 2b. Surefire SOCOM762-RC2 (SOCOM 3-Prong Flash Hider) Bolt Action 300 BLK Muzzle Sound Pressure Signature, Short Time Window, 24-OCT-2020
Figure 3a. Surefire SOCOM762-RC2 (SOCOM 3-Prong Flash Hider) Bolt Action 300 BLK Muzzle Sound Impulse Signature, 24-OCT-2020
Figure 3b. Surefire SOCOM762-RC2 (SOCOM 3-Prong Flash Hider) Bolt Action 300 BLK Muzzle Sound Impulse Signature, 24-OCT-2020
The Surefire SOCOM762-RC2 displays perceptible FRP to bystanders; it is more pronounced in the impulse regime (Figure 3) than in the pressure regime (Figure 2). As discussed above, although the SOCOM762-RC2 generates relatively low back pressure, its suppression method still allows for marginal trapping of gas. This is evident in the coupled bullet endcap exit and precursor flow measured at approximately 29.9 ms in Figure 1. In addition to the holistic waveform, an immediate indicator of precursor flow coupling with the bullet exit is the higher initial N-wave amplitude measured in Shot 1 (Figure 2b). Although the bullet exit is extremely similar from shot to shot, the first shot has ancillary combustion in its precursor flow that is not insignificant.
PEW Science Note 1: The increase in back pressure from the SOCOM762-RC2 compared with that of the OSS HX-QD 762 is not extremely significant, but the suppression mechanisms are different enough that the early-time flow is restricted. Subsonic suppression performance is highly dependent upon back pressure generation; it is the primary mechanism of subsonic sound signature suppression in most small arm weapon system silencers. The reader is encouraged to examine the performance of other silencers in similar Omega Metric ranges as defined in PEW Science Public Research Supplement 6.40. The supersonic suppression performance of the SOCOM762-RC2 and the HX-QD 762 are similar, with the subsonic performance differing noticeably. This is also discussed in Section 6.46.3, below.
PEW Science Note 2: PEW Science previously evaluated the supersonic performance of the Surefire SOCOM762-RC2 with both the SOCOM 3-prong flash hider and the WARCOMP muzzle brake in Sound Signature Review 6.26. PEW Science has not evaluated the subsonic performance of this silencer with the WARCOMP mount. Based on the test results and analysis previously presented, PEW Science postulates that subsonic suppression performance with the WARCOMP will be lower than with the SOCOM 3-prong flash hider, due to excessive gas leakage at the mount interface from close mount port proximity to the mount collar and different seal geometry. The degree of performance differential is postulated to be lower with 300 BLK subsonic than with .308 supersonic, but testing is needed to verify this phenomenon.
The FRP of the SOCOM762-RC2 in the subsonic flow regime is noticeable but not severe. 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.
With subsonic 300 BLK from an 8-inch barrel, the SOCOM762-RC2 is noticeably quieter to bystanders than it is with supersonic .308 from a 20-in barrel. Direct comparisons with other silencers are provided in Section 6.46.2 and 6.46.3, below.
6.46.2 Suppression Rating Comparison - Subsonic 300 BLK
The Surefire SOCOM762-RC2 suppressor is intended to possess high mass flow rate (low back pressure; low PEW Science Omega metric) while exhibiting moderate sound suppression (exhibiting a moderate PEW Science Suppression Rating). As previously discussed, its subsonic sound signature suppression performance is not extreme but it is respectable for the back pressure generated by the silencer. Figure 6 shows a performance comparison of the eight .30 rifle silencer configurations tested with the subsonic 300 BLK cartridge shown in public PEW Science testing, to date. Unsuppressed and suppressed Suppression Ratings are shown for both the shooter and bystanders.
Figure 6. Suppression Rating Comparisons Of .30 Rifle Silencers Using PEW-SOFT 300 BLK Subsonic Test Data
The mass flow rate of the Surefire SOCOM762-RC2 is high, but the baffles are numerous enough, and possess enough conventional gas-trapping features, such that it reaches sound suppression performance with subsonic 300 BLK between that of compact and midsize .30 silencers on the market. This lower subsonic suppression performance for a full-size silencer like the SOCOM762-RC2 is a physical consequence of the silencer’s back pressure reducing design. The Suppression Rating 1.0 m left of the endcap is two categories lower than that of the Sig SRD762Ti-QD (Review 6.39), which represents a significant gap in sound suppression performance. However, the Suppression Rating of the SOCOM762-RC2 is a category higher than that of the OSS HX-QD 762 (Review 6.45) with subsonic 300 BLK, which is a meaningful performance differential due to both silencers exhibiting relatively low back pressure. Although the OSS HX-QD 762 back pressure is extremely low, some users may not require that extreme for weapon operation. Therefore, the performance balance of the SOCOM762-RC2 across the two flow regimes may be more attractive. Section 6.46.3, below, presents quantitative back pressure metrics alongside supersonic and subsonic Suppression Ratings for the silencers, for direct comparison.
Interestingly, the SOCOM762-RC2 almost reaches the at-ear Suppression Rating of the unwiped Energetic Armament VOX S (Review 6.25) on this weapon system, despite having lower flow restriction (lower back pressure). This is due to the baffle porting in the SOCOM762-RC2; despite being a longer silencer with more baffles, its technology has a higher mass flow rate than the simple non-ported cone baffles in the Energetic Armament VOX S silencer.
The propensity of a rifle silencer to exhibit differing sound signature suppression in the supersonic and subsonic flow regimes is typical. To illustrate the differing sound suppression phenomena, detailed comparative analysis of the SOCOM762-RC2 in both flow regimes is presented below, along with summary data for three other silencers.
6.46.3 Suppression Rating Comparison - Subsonic 300 BLK vs. Supersonic .308
The sound suppression performance of four silencers in both the supersonic and subsonic flow regimes are compared in Figure 7, below. The solid colors in the plot denote supersonic .308 performance, whereas the typical shaded patterns denote subsonic 300 BLK performance. As the PEW Science Suppression Rating is a universal sound signature metric based upon the response of the human inner ear, all metrics in this plot are comparable to each other, regardless of cartridge. The PEW Science Suppression Rating is the only sound signature metric that allows the comparison of human inner ear response to fast transients, across all suppressed weapon system platforms.
PEW Science has also developed an empirical relation to quantify the back pressure (flow restriction) of silencers. Omega Zones are intended to provide guidance to weapons developers, silencer designers, and end-users, with regard to flow restriction characteristics of different silencer designs. It is very important to note that silencers possessing a relatively high Ω can still provide functional use on weapon systems. Some weapon systems are more sensitive to Ω than others.
Figure 7. Suppression Rating Comparisons Of .30 Rifle Silencers Using PEW-SOFT 300 BLK Subsonic and .308 Supersonic Test Data
There is a significant amount of data presented in Figure 7, above. The reader is encouraged to observe the plot legend and notes, such that the data is viewed and interpreted in the appropriate context.
The sound suppression performance of the SOCOM762-RC2 in the subsonic flow regime is similar to that of the YHM Resonator K (Review 6.32) but its supersonic performance is a category higher. With only marginally higher back pressure, the SOCOM762-RC2 is, overall, a more balanced silencer than the Resonator K, albeit much larger and heavier.
As previously discussed, the supersonic suppression performance of the Surefire SOCOM762-RC2 (Review 6.26) is similar to that of the OSS HX-QD 762 (Review 6.41), but the subsonic performance of the SOCOM762-RC2 is less handicapped, despite its low back pressure. Unlike the OSS HX-QD 762 (Review 6.45), the SOCOM762-RC2 data and analysis presented in this article indicates that the conventional baffle characteristics of the Surefire silencer are favorable for subsonic suppression. The suppression mechanism of the OSS HX-QD 762 does not excel below a certain pressure and combustion duration threshold.
The Energetic Armament VOX S (multiple reviews) employs a primitive non-ported straight cone design and the performance metrics in Figure 7 illustrate this. The Surefire SOCOM762-RC2 is able to not only outperform the Energetic Armament VOX S in the supersonic flow regime and do so with lower back pressure, but it almost reaches the same at-ear Suppression Rating with subsonic 300 BLK on the tested host weapon platform. This is due to the length of the SOCOM762-RC2 placing the silencer endcap orifice (and therefore the pressure emitting origin) further away from the shooter’s ear, as well as the higher number of baffles in the SOCOM762-RC2, which makes up for its higher mass flow rate (lower back pressure) in the subsonic flow regime. Again, flow restriction is paramount for subsonic 300 BLK performance in many silencer designs.
PEW Science Research Note: The performance differentials shown in Figure 7 are not only due to peak sound pressure. Multiple waveform characteristics comprise a silencer’s holistic sound signature. PEW Science postulates that most readers and silencer users have never been presented with information indicating that silencers perform differently in different flow regimes, anecdotal experience notwithstanding. In addition to combustion duration, the time at which peak positive phase pressure is reached, its duration, and its impulse accumulation, are factors that may significantly influence the interpretation of a sound signature to the human ear. To further illustrate the physical behavior of the SOCOM762-RC2 design, detailed waveform comparisons of the silencer in both flow regimes are presented below.
Figure 8a presents the first round sound signatures of the Surefire SOCOM762-RC2 silencer in the supersonic and subsonic flow regimes, respectively, in pressure space. The same comparison is shown in impulse space, in Figure 8b.
Figure 8a. Surefire SOCOM762-RC2 (SOCOM 3-Prong Flash Hider) Supersonic .308 And Subsonic 300BLK Bolt Action Rifle Muzzle Sound Pressure Signature Comparison (FRP)
Figure 8b. Surefire SOCOM762-RC2 (SOCOM 3-Prong Flash Hider) Supersonic .308 And Subsonic 300BLK Bolt Action Rifle Muzzle Sound Impulse Signature Comparison (FRP)
The Surefire SOCOM762-RC2 exhibits marginally higher peak sound pressure with supersonic .308 from a 20-in barrel, than it does with subsonic 300 BLK from an 8-in barrel. However, that is not the primary reason for the 300 BLK weapon system being quieter with this silencer (having a higher PEW Science Suppression Rating). There are other factors that significantly influence the true loudness:
Although the peak sound pressure in both waveforms in Figure 8a are similar, note the significantly delayed onset of peak sound pressure in the 300 BLK subsonic waveform; the bullet exit is plainly decoupled from the primary muzzle blast, and precursor flow suppressed to a level that only allows venting at the time of bullet exit. The flow restriction of the the SOCOM762-RC2 is high enough to trap enough gas for subsonic 300 BLK sound suppression to be marginally effective.
The positive phase impulse accumulation (Figure 8b) of the SOCOM762-RC2 in the subsonic flow regime not only exhibits a significantly delayed peak onset, but is significantly lower than the impulse in the subsonic flow regime. This behavior is expected in a conventional silencer suppressing these cartridges. The relative rise-time delay in the subsonic 300 BLK waveform demonstrates balanced trapping of gas, even with low backpressure.
To illustrate how FRP can be more significant in the subsonic flow regime than in the supersonic flow regime, and that examination of the waveforms in impulse-space is required to demonstrate that phenomenon, the exercise is repeated below in Figure 9a and Figure 9b.
Figure 9a. Surefire SOCOM762-RC2 (SOCOM 3-Prong Flash Hider) Supersonic .308 And Subsonic 300BLK Bolt Action Rifle Muzzle Sound Pressure Signature Comparison (Shot 2)
Figure 9b. Surefire SOCOM762-RC2 (SOCOM 3-Prong Flash Hider) Supersonic .308 And Subsonic 300BLK Bolt Action Rifle Muzzle Sound Pressure Signature Comparison (Shot 2)
The exact same phenomena observed during Shot 1 in both supersonic and subsonic flow regimes with the SOCOM762-RC2 that were observed in Figure 8 are again observed in Figure 9. Although the peak sound pressure in the two flow regimes is extremely similar, the timing and impulse accumulation is vastly different. The Surefire SOCOM762-RC2 is significantly quieter with subsonic 300 BLK than it is with supersonic .308, despite its low back pressure. Future PEW Science testing of the Surefire SOCOM300 SPS is postulated to demonstrate the efficacy of similar Surefire baffle technology applied in a higher back pressure design.
6.46.4 Review Summary: Surefire SOCOM762-RC2 on a Q mini FIX 300 BLK with 8-in Barrel
When paired with the Q mini FIX 8” 300 BLK and fired with Discreet Ballistics 190gr Subsonic Target ammunition, the Surefire SOCOM762-RC2 with the SOCOM 3-Prong flash hider achieved a Suppression Rating™ of 44.0 in PEW Science testing.
PEW Science Subjective Opinion:
The Surefire SOCOM762-RC2 is a full-size 30 caliber machine gun rated rifle silencer that possesses competitive sound signature suppression performance in the supersonic flow regime with many silencers on the market, while also possessing significantly reduced back pressure. The performance of the SOCOM762-RC2 represents an outlier in the market due to the back pressure performance. Due to this reduction in back pressure, the subsonic suppression performance of the SOCOM762-RC2 suffers. However, its length, along with its type and quantity of baffles, enable it to achieve subsonic suppression performance similar to that of many compact to mid-size .30 rifle silencers on the current market.
Full-size .30 rifle silencers exhibiting low flow restriction (low back pressure) are relatively uncommon in the current market. The SOCOM762-RC2 performs as well in the subsonic flow regime as can be expected with the technology it employs for back pressure reduction. The contrast in methods used by the tested OSS HX-QD 762 and the SOCOM762-RC2 have been characterized by PEW Science, in detail. PEW Science encourages users to examine silencer performance in the specific flow regime of interest for their desired application.
Two mounts were used in the previous testing of this silencer in the supersonic flow regime. Only the SOCOM 3-Prong Flash Hider was used to test the silencer with subsonic 300 BLK. The highly irregular performance of this silencer with the WARCOMP mount at the shooter’s head position in previous testing precludes further testing of this silencer with the WARCOMP mount, at least for the near future.
Surefire advises that the WARCOMP mount, while able to be used with the SOCOM762-RC2, is intended for operators that are using their weapon unsuppressed and may use their silencer to suppress their weapon system infrequently. The WARCOMP may provide an enhancement to shooting dynamics when unsuppressed, and these benefits are part of the intended design. Note that PEW Science has not performed an in-depth evaluation of the WARCOMP without a silencer mounted. For users that may only seldomly suppress their weapon system, the WARCOMP mount may offer benefits that make it an attractive choice. However, for unsuppressed subsonic 300 BLK use, PEW Science postulates the WARCOMP does not offer substantial benefits to the operator. This is due to the lower combustion duration of the subsonic 300 BLK cartridge and the shorter barrel of typical 300 BLK weapon systems, resulting in differing weapon system dynamics.
The use of the Surefire locking collar is relatively straight forward. Note that some users have indicated carbon build-up on the mount that may prevent an operator from removing the silencer. Furthermore, carbon buildup may result in the silencer not being properly aligned upon reattaching; this misalignment may result in baffle strikes. PEW Science has experienced this in testing and highly recommends users of the Surefire mounting system clean their mounts regularly.
In this review, the Surefire SOCOM762-RC2 performance metrics depend upon suppressing a subsonic intermediate rifle cartridge. While the sound signature of such cartridges can be suppressed to levels that may result in the desire of the shooter and bystanders to not wear hearing protection, PEW Science encourages the reader to remain vigilant with regard to all subsonic rifle cartridge suppression claims. The gas volume and combustion products created by firing a subsonic intermediate rifle cartridge such as 300 BLK are still significant; the measured pressure and impulse magnitudes, and their durations, illustrate this fact. The subsonic suppression performance of the SOCOM762-RC2 is lower than other silencers of similar size.
The hearing damage potential of subsonic rifle use is not insignificant. PEW Science encourages the reader to consider the Suppression Rating when deciding on an appropriate silencer and host weapon combination for their desired use.
