SSS.6.26 - Surefire SOCOM762-RC2 and the Savage Model 10 PC .308 (Free Version)
/Surefire SOCOM762-RC2 on the Savage Model 10 .308 with 20-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 results from two separate tests. The SOCOM762-RC2 was first tested by PEW Science on 09-MAY-2020 with the WARCOMP flash hider mount. Significant anomalies were noted in the test. As a result, PEW Science repeated the test on the same SOCOM762-RC2 silencer on 24-OCT-2020, this time with the SOCOM 3-Prong flash hider mount instead of the WARCOMP mount, with the same host weapon and ammunition. The SOCOM 3-Prong flash hider mount is non-ported and contains so-called “labyrinth seals,” the presence of which result in significantly different gas dynamics than a ported WARCOMP equipped SOCOM762-RC2 system at the mount interface.
Caution: The free version of this review does not show waveform data measured at the shooter’s ear. Readers who are not members of PEW Science, and are therefore not able to view the member data, are encouraged to note the Suppression Ratings at the ear in the above Rating graphic. PEW Science does not recommend use of the WARCOMP mount on this platform, for most users. Personal protective equipment (PPE), including eye and ear protection, is recommended for the operation of suppressed small arms, in general.
Both sets of test results in this Sound Signature Review are of the SOCOM762-RC2 on the Savage Model 10 Precision Carbine bolt-action rifle, chambered in .308WIN with a 20-inch barrel. Federal XM80C 149gr ammunition was used in the tests.
Section 6.26.1 contains the results of the latest test with the SOCOM 3-Prong flash hider mount.
Section 6.26.2 contains the results with the WARCOMP flash hider mount.
Section 6.26.3 contains an in-depth comparison of the sound signatures and flow dynamics of the two mount systems.
Section 6.26.4 contains relative back pressure and Suppression Rating comparisons with selected .30 rifle silencers.
Section 6.26.5 contains the review summary and subjective PEW Science opinions.
Summary: When paired with the Savage M10 20” .308 and fired with Federal XM80C, the Surefire SOCOM762-RC2 mounted with the SOCOM 3-Prong flash hider achieved a Suppression Rating™ of 38.4 in PEW Science testing. When mounted with the WARCOMP flash hider on the same host weapon and fired with the same ammunition, the SOCOM762-RC2 achieved a Suppression Rating of 24.8.
6.26.1 SOCOM762-RC2 Sound Signature Test Results (SOCOM 3-Prong Flash Hider)
A summary of the principal Silencer Sound Standard performance metrics of the SOCOM762-RC2 tested with the 3-Prong Flash Hider 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
6.26.1.1 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.
Figure 1 shows a 2.7 millisecond long portion of the first round sound pressure signature of the SOCOM762-RC2 as measured 1.0 m left of the muzzle. There are three significant waveform features labeled:
An initial pressure pulse out of the silencer, after the bullet exits the end-cap, causes a 150.2 dB peak.
As gas continues to exit the silencer from the primary combustion event, the measured sound pressure amplitude expediently drops to 124.2 dB.
Secondary jetting then begins with a latent peak reaching a peak sound overpressure amplitude of 151.2 dB.
This is a somewhat unusual sequence observed when firing supersonic .308WIN ammunition from a bolt-action rifle with an attached silencer; these waveform characteristics indicate that the SOCOM762-RC2 exhibits low early-time flow restriction (back pressure). Internal silencer design can significantly influence the measured timing and pressure amplitudes. A back pressure comparison with selected silencers is shown in Section 6.26.4.
Fig 1. SOCOM762-RC2 First Round .308 Bolt Action Rifle Muzzle Sound Pressure Signature, 24-OCT-2020
Closer views of the first peak of all shots (Fig 2a) and highest peak of the first shot (Fig 2b) are shown below. Figure 2a illustrates the consistency of the bullet end-cap exit event (and combined major first jet) between all 5 shots during the test. Figure 2b shows points later in time during Shot 1 as the maximum sound pressure occurs from the primary combustion event. Note that the total timescale displayed in Figure 2a is 0.2 milliseconds (200 microseconds) and the total timescale in Figure 2b is only 0.1 milliseconds (100 microseconds). PEW-SOFT provides a sampling point every microsecond and the individual data points are shown in Figure 2b to illustrate this.
Fig 2a. SOCOM762-RC2 .308 Bolt Action Rifle Muzzle Sound Pressure First Peaks 1, 24-OCT-2020
Fig 2b. SOCOM762-RC2 First Round .308 Bolt Action Rifle Muzzle Sound Pressure FRP Peak, 24-OCT-2020
The primary sound signature pressure histories for all 5 shots with the SOCOM762-RC2 are shown in Figure 3a. The sound signatures of Shot 1 and Shot 2 are shown in Figure 3b, in the regions of peak sound pressure. Note the same peak events are labeled for Shot 1 that were previously labeled in Figure 1. The real sound impulse (momentum transfer potential) histories from the same 5-shot test are shown in Figure 4a. In Figure 4b, a shorter timescale is shown comparing the impulse of Shot 1 to that of Shot 2.
Fig 3a. SOCOM762-RC2 .308 Bolt Action Rifle Muzzle Sound Pressure Signature, 24-OCT-2020
Fig 3b. SOCOM762-RC2 Peak View of Muzzle Sound Pressure Signature, 24-OCT-2020
Figure 4a. SOCOM762-RC2 .308 Bolt Action Rifle Muzzle Sound Impulse Signature, 24-OCT-2020
Figure 4b. SOCOM762-RC2 .308 Bolt Action Rifle Muzzle Sound Impulse Signature, 24-OCT-2020
The measured first-round-pop (FRP) is visible in both the pressure and impulse regimes, in peak amplitudes, timing, and wave shapes. Note that after the initial impulse step peak occurs at approximately 30 ms, the impulse of Shot 1 has a steeper slope than the impulse of subsequent shots (Fig. 4). The fastest rise-time to peak impulse occurs in Shot 1, as expected. PEW Science in-depth human inner-ear analysis of the waveforms measured at the muzzle indicates that the FRP may not be significant to bystanders.
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 bolt action rifle firearm configuration.
PEW Science note: One notable observation from the measured data is the relatively short rise-time to peak impulse exhibited by the SOCOM762-RC2 in this test, when compared to that of all of the other .30 rifle silencers shown in public PEW Science testing, to date. The rise-time to peak impulse (peak momentum transfer potential) measured 1.0 meter left of the muzzle, of the SOCOM762-RC2, after the first shot when firing supersonic .308WIN ammunition, is measured to be significantly faster than silencers of similar size and Suppression Rating. This is one objective measurement that indicates the SOCOM762-RC2 exhibits relatively high gas flow rate and therefore relatively low back pressure characteristics. More detailed and direct comparisons are provided in Section 6.26.4 of this review.
As typically indicated, first-round sound signatures always differ from subsequent shots, as the atmosphere within the silencer changes. The FRP phenomenon cannot always be shown by viewing only the peak sound pressure. This is one of the reasons why The Silencer Sound Standard requires examining multiple sound signature metrics. Ammunition consistency can play a role in the determination of FRP, however, the close examination of measured pressure and impulse waveforms typically excludes ammunition from the possible factors influencing true FRP, due to the relative consistency of most high quality factory ammunition.
As shown above, FRP significantly influences rise time to peak impulse. Therefore, FRP waveforms must be excluded from the data set when formulating flow rate (back pressure) calculations that utilize the waveform data from subsequent shots.
6.26.2 SOCOM762-RC2 Sound Signature Test Results (WARCOMP Flash Hider)
A summary of the principal Silencer Sound Standard performance metrics of the SOCOM762-RC2 tested with the WARCOMP Flash
Hider is shown in Table 2. The data acquired 1.0 m (39.4 in) left of the muzzle is available for viewing to all. As stated in Section 6.26.1, 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 2. Surefire SOCOM762-RC2 (WARCOMP Flash Hider) Sound Metric Summary
6.26.2.1 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.
The primary sound signature pressure histories for all 5 shots with the SOCOM762-RC2 on the WARCOMP are shown in Figure 7a. The sound signatures of Shot 1 and Shot 2 are shown in a smaller time window in Figure 7b. The real sound impulse (momentum transfer potential) histories from the same 5-shot test are shown in Figure 8a. In Figure 8b, a shorter timescale is shown comparing the impulse of Shot 1 to that of Shot 2.
Fig 7a. SOCOM762-RC2 .308 Bolt Action Rifle Muzzle Sound Pressure Signature, 09-MAY-2020
Fig 7b. SOCOM762-RC2 .308 Bolt Action Rifle Muzzle Sound Impulse Signature, 09-MAY-2020
Figure 8a. SOCOM762-RC2 .308 Bolt Action Rifle Muzzle Sound Impulse Signature, 09-MAY-2020
Figure 8b. SOCOM762-RC2 Bolt Action Rifle Muzzle Sound Impulse Signature, 09-MAY-2020
As was shown in the test with the 3-Prong Flash Hider, the measured first-round-pop (FRP) with the WARCOMP mount is evident when comparing Shot 1 to Shot 2 (Fig 8b). Note that the FRP of the SOCOM762-RC2 with the WARCOMP is evident in both time phasing, and in peak impulse amplitude.
Irregularities in the wave shapes are noted with the WARCOMP, when compared to the test using the 3-Prong Flash Hider. Direct comparisons are provided in Section 6.26.3 of this review. Despite these irregularities, the overall late-time shapes of the impulse waveforms measured at the muzzle, from shot-to-shot, are consistent, highlighting the silencer’s overall sound performance consistency at the muzzle after the FRP, as well as the relative consistency of the tested firearm configuration. Note the highly irregular early-time gas jetting of the first shot in Figure 7b.
PEW Science note: The muzzle sound signature of the SOCOM762-RC2 is more severe when using the WARCOMP mount; although the peak amplitudes are not significantly different, the wave shape and timing varies. There is a significant change in gas dynamics with the WARCOMP mount due to early-time gas venting from the mount interface; this is apparent in the muzzle waveforms, as flow re-direction results in delay of muzzle jetting in early time. Again, Section 6.26.3 of this review contains direct comparison of the WARCOMP and 3-Prong Flash Hider. This phenomenon is examined in further detail in the at-ear waveforms available in the Members-Only version of this review. The at-ear waveform differences are extremely significant.
6.26.3 SOCOM 3-Prong Flash Hider and WARCOMP Flash Hider Mount Comparison
Below, direct comparisons of the measured pressure and impulse waveforms with the two different mounts used in the two tests of the SOCOM762-RC2 are shown. The data acquired 1.0 m (39.4 in) left of the muzzle is available for viewing to all. Data acquired 0.15 m (6 in) right of the shooter’s right 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.
Figure 11a and Figure 11b show first-shot muzzle overpressure and impulse comparisons, respectively. These comparisons directly illustrate the changes in gas dynamics at the muzzle due to WARCOMP mount leakage at the silencer-mount interface.
Fig 11a. SOCOM762-RC2 .308 Bolt Action Rifle Muzzle Sound Pressure Signatures - Mount Comparison
Fig 11b. SOCOM762-RC2 .308 Bolt Action Rifle Muzzle Sound Impulse Signatures - Mount Comparison
The 3-Prong Flash Hider is non-ported and equipped with “labyrinth seals;” these circumferential machined ridges on the mount help to prevent gasses from flowing aft toward the shooter. By providing this greater gas seal than the non-seal equipped and ported WARCOMP, the labyrinth seal system allows gas flow to form a silencer-muzzle jet earlier in time. In contrast, the WARCOMP mount allows gas to vent directly to atmosphere at the mount interface of the silencer (at-ear waveforms demonstrate this significant phenomenon and are only available in the member version of this review). As a result of this venting with the WARCOMP, silencer-muzzle jet formation is delayed as flow is diverted out of the mount interface and silencer muzzle simultaneously. This silencer-muzzle jet formation delay with the WARCOMP is illustrated in Figure 11a. Eventually, the overall impulse signature reaches similar characteristics with both mounts (Fig 11b). Nonetheless, the waveform time phasing and amplitude differences in early time when using the WARCOMP mount are significant enough to lower the Suppression Rating at the muzzle; the muzzle sound signature is therefore more severe to the human ear with the WARCOMP than with the 3-Prong Flash Hider. This may not be intuitive to some users, as mount leakage is most often associated with at-ear signature differences. While not as severe at the muzzle as at the ear, the difference in muzzle signature with the WARCOMP is notable.
6.26.4 Relative Back Pressure and Suppression Rating Comparison (.30 Rifle Silencers)
PEW Science Research Note: As of February 2021, back pressure characterization has undergone refinement and Rev.2 of the Back Pressure Metric has been developed. Research is ongoing. Please see back pressure research updates starting with Sound Signature Review 6.36.
The SOCOM762-RC2 is intended to exhibit low back pressure. PEW Science is currently conducting silencer back pressure research. Figure 13 shows preliminary relative supersonic suppression and back pressure comparisons between selected 7.62mm (30 caliber) rifle silencers shown in public PEW Science Sound Signature Reviews, as of the date of this review publication. The results shown in Figure 13 are calculated from real test data acquired with PEW-SOFT. Please note the following:
The time to reach peak gas momentum transfer potential, as measured 1.0 m left of the weapon muzzle, is the objective quantity used to generate the back pressure data summary.
The waveform characteristics of unsuppressed shots with the same ammunition used in the respective tests are used in the calculations and the unsuppressed relative back pressure and Suppression Rating quantities are shown.
The first shot from each silencer test is omitted from the back pressure computations due to internal gas environment characteristics within the silencer (FRP) that influence peak impulse amplitude, wave-shape, and timing. All unsuppressed shots are included.
Back Pressure Data is normalized to the silencer with the highest back pressure shown, which is the Thunder Beast ULTRA 9.
Figure 13. Back Pressure and Suppression Rating Comparisons of .308 Rifle Silencers using PEW-SOFT Data
From the above data, it can be concluded that the SOCOM762-RC2 suppressor may produce significantly low back pressure, when compared to silencers of similar size and sound suppression performance, in the supersonic flow regime. It is predicted to exhibit 83% lower back pressure than the Thunder Beast ULTRA 9, which is an extreme performance differential. It is very interesting to note that the severity of the sound signature at the shooter’s ear with the Surefire SOCOM762-RC2 is very similar to that of the SilencerCo Omega 300, yet the SOCOM762-RC2 is predicted to possess significantly lower back pressure. This combination of sound suppression performance and low back pressure is unusual for silencers in the current market.
It is important to note that the back pressure potential of silencers may not be significant in practical use with semi-automatic and automatic hosts, depending on the respective metric magnitudes; this is the subject of future PEW Science research. For example, it is postulated that there is a threshold relative back pressure metric below which adequate semi-automatic weapon function on 5.56x45mm host weapons may be achieved. Whether that threshold is 0.57 in Figure 13 (Omega 300) or 0.67 (Sandman-L), for example, will depend on the particular host weapon configuration. Recent PEW Science research at the time of this review publication indicates that a back pressure metric threshold is probable for gas operated 5.56x45mm small arms. Further research is ongoing.
PEW Science note: The relative back pressure percentages described in this section are only valid when examining the data normalized to the Thunder Beast ULTRA 9 in Figure 13. PEW Science back pressure research is ongoing. Membership contributions to PEW Science help fund such research.
The SOCOM762-RC2 is on-par with the sound suppression performance of several full-size 30 caliber rifle silencers, but is predicted to exhibit significantly lower back pressure. The SOCOM762-RC2 achieves a very similar level of sound suppression to the Q Thunder Chicken and Rugged Surge in its long configuration, measured at the muzzle. The signature severity of the SOCOM762-RC2 at the shooter’s ear is similar to that of the Sandman-L and SilencerCo Omega 300. Again, note that its back pressure is significantly lower.
6.26.5 Review Summary: SOCOM762-RC2 on the Savage Model 10 .308 with 20-in Barrel
When paired with the Savage M10 20” .308 and fired with Federal XM80C, the Surefire SOCOM762-RC2 mounted with the SOCOM 3-Prong flash hider achieved a Suppression Rating™ of 38.4 in PEW Science testing. When mounted with the WARCOMP flash hider on the same host weapon and fired with the same ammunition, the SOCOM762-RC2 achieved a Suppression Rating of 24.8.
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 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. Although the back pressure computations from the impulse rise-time data in PEW Science testing are preliminary and require further rigorous validation, the computations from these measurements have been shown to correlate with semiautomatic and automatic host weapon system dynamics; specifically, noted correlation with cyclic rate and gas system settings for small arm system operation. Those correlations, in conjunction with Surefire’s design intent of lower back pressure with the SOCOM762-RC2, indicate a high probability that the SOCOM762-RC2 possesses lower flow restriction, and thus lower back pressure. This classification is not only relative to silencers of its size, but relative to centerfire .30 rifle silencers, in general. It should be emphasized that this is highly atypical.
Two mounts were used in the testing of this silencer. PEW Science was fortunate to be able to test the exact same silencer, twice, with both the WARCOMP and SOCOM 3-Prong Flash Hider. The highly irregular performance of the silencer with the WARCOMP mount at the shooter’s position was troubling, and PEW Science discussed the results with Surefire.
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 provides 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.
The SOCOM 3-Prong Flash Hider with “labyrinth seals” and no porting offers significantly different suppressed performance than the WARCOMP with the SOCOM762-RC2. The seals are marketed by Surefire to prevent aft gas leakage at the mount interface. PEW Science data indicates that this claim is true, but the absence of ports is postulated to be a significant factor.
PEW Science highly recommends the use of a non-ported “labyrinth seal” equipped mount with the SOCOM762-RC2 for the reasons stated in this review. It is possible that prolonged use of a ported WARCOMP with a silencer could result in higher sight or hearing risk to an operator if not properly equipped with the recommended PPE. Hearing and eye protection is recommended for the operation of suppressed small arms, in general.
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 SOCOM762-RC2 performance metrics depend upon suppressing a supersonic centerfire rifle cartridge; no easy task. PEW Science encourages the reader to remain vigilant with regard to all supersonic centerfire rifle suppression claims. The gas volume and combustion products created by the firing of the supersonic .308WIN cartridge are significant; the measured pressure and impulse magnitudes, and their durations, illustrate this fact.
The hearing damage potential of supersonic centerfire rifle use is significant. PEW Science encourages the reader to consider the Suppression Rating when deciding on an appropriate silencer and host weapon combination for their desired use.
