SSS.6.107 - Sig Sauer SLH300TI and the Q mini FIX 300 BLK Subsonic
/Sig Sauer SLH300TI on a Q mini FIX 300 BLK with 8-in Barrel
The SLH300TI is designed and manufactured by Sig Sauer. It is a 30 caliber centerfire rifle silencer, intended to suppress most cartridges with projectiles appropriately sized to travel through the bore; it is described by Sig Sauer as a 300 BLK silencer. It has a 1.6-inch diameter and is 8.9 inches in length. The silencer is available as a 5/8”-24tpi 25-degree tapered direct-thread model, which is the model tested. The silencer is also available as a quick-detach model, that may be used with their Clutch-LOK QD mounting system. The two types of silencers are identical in internal construction. The silencer is constructed of Direct Metal Laser Sintered (DMLS, or “3D Printed”) titanium, and weighs 12.3 ounces. Variations of the Sig SLH series may be obtained from Silencer Shop; however, at the time of this article publication, this tested model may not be available.
This review contains single-test results using the Sig Sauer SLH300TI direct-thread mounted to 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 6.107.1 contains the Sig Sauer SLH300TI test results and analysis.
- Section 6.107.2 contains Suppression Rating comparisons with selected .30 rifle silencers in the subsonic flow regime.
- Section 6.107.3 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 Sig Sauer SLH300TI achieved a Suppression Rating™ of 44.8 in PEW Science testing. As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.
Relative Suppression Rating Performance is Summarized in SSS.7 - PEW Science Rankings
6.107.1 Sig Sauer SLH300TI Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Sig Sauer SLH300TI 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. Sig Sauer SLH300TI Sound Metric Summary
6.107.1.1 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 2.7-millisecond long sequence of events during the first test shot with the Sig Sauer SLH300TI, as measured 1.0 m left of the muzzle. There are five significant events labeled:
During combustion within the weapon system, a 109.4 dB peak is measured.
Precursor flow through the silencer is suppressed, and a peak of 124.1 dB is measured during this initial jetting.
The first major jet peaks at an amplitude of 143.3 dB.
Primary jetting results in a peak overpressure amplitude measured to be 147.5 dB, which is the highest of the first shot.
Decay is exhibited relatively expediently in the signature, and a latent pulse of 133.7 dB is noted.
This is a typical sequence observed when firing subsonic 300 BLK ammunition from a bolt-action weapon system with an attached silencer that exhibits relatively low flow restriction (low back pressure); internal silencer design can significantly influence the measured timing and pressure amplitudes. Supersonic 7.62x51mm and supersonic 300 BLK test data using the Sig Sauer SLH300TI are the subject of future PEW Science publications. A derivation of the PEW Science Back Pressure Metric, Ω [Pa-1], is presented in PEW Science Public Research Supplement 6.40.
Fig. 1 Early-Time Shot History, Sig Sauer SLH300TI Bolt Action 300 BLK Muzzle Sound Pressure Signature
The Sig Sauer SLH300TI shares extremely similar internal geometric features with legacy Sig Sauer silencer designs such as with the Sig SRD762Ti-QD (Review 6.39). The cone baffle design in the primary core of the silencer mirrors that of the legacy SRD series, as well as evolutions of that design from Q, such as in the Full Nelson (Review 6.99), Half Nelson (Review 6.29), Trash Panda (Review 6.4 and Review 6.61), and Thunder Chicken (Review 6.20).
However, in addition to the straight ported cones possessed by the SLH300TI, it also possesses outer annular cavities, exterior to the primary baffle geometry. This annulus is accessed through porting distributed throughout the outside edges of the baffle stack. The distal end of the silencer is vented; it is through this venting that the annular gas is exhausted to atmosphere. While this hybrid design shares similarities with various other 3D-printed designs from other manufactures like CGS in their Hyperion Technology and HUXWRX in their Flow-Through technology, it is considerably different in that the annular cavity exchanges pressure with the primary flow path in numerous locations. PEW Science postulates that this relatively simple design that combines annular flow with straight cones exhibits a relatively high flow rate at the expense of suppression performance; the test data and analysis in this report strongly supports this conclusion.
PEW Science Research Note 1: One indicator of the high flow rate (low backpressure) of the Sig Sauer SLH300TI design is the rapid pressure accumulation at high amplitude noted in Figure 1, with expedient decay. This rapid gas propagation in early time, as well as rapid decay, is repeated throughout the shot string, albeit with successive jet delay as the string continues.
PEW Science Research Note 2: The SIG SLH300TI exhibits a PEW Science Suppression Rating on the subsonic 300 BLK mini Fix bolt action test platform that is considerably lower than other silencers of its size tested by PEW Science, to date. To bystanders, the 300 BLK signature suppression of the SLH300TI is on par with that from the Surefire SOCOM762-RC2 (Review 6.46); another full-size silencer that exhibits a relatively high flow rate. To the shooter, the SLH300TI is on-par in severity with the aforementioned Surefire silencer and the unwiped configuration of the Energetic Armament VOX S (Review 6.25) on this platform.
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 two 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. Sig Sauer SLH300TI Bolt Action 300 BLK Muzzle Sound Pressure Signature
Fig 2b. Sig Sauer SLH300TI Bolt Action 300 BLK Muzzle Sound Pressure Signature, Short Time Window
Figure 3a. Sig Sauer SLH300TI Bolt Action 300 BLK Muzzle Sound Impulse Signature
Figure 3b. Sig Sauer SLH300TI Bolt Action 300 BLK Muzzle Sound Impulse Signature
The Sig Sauer SLH300TI produces minimally perceptible first-round-pop (FRP) to bystanders. This is notable for a high flow rate design; however, as all the shots produce a relatively severe signature for the silencer’s size, the impact of this FRP suppression performance is not as significant as it would be were the signature more significantly suppressed. It should be noted that this test is in the subsonic 300 BLK combustion regime, where overall signature suppression may be of paramount importance for many end users.
It is interesting to note that despite the relatively low impact of the ancillary combustion during FRP to the signature severity, hallmark signs of the FRP are exhibited in pressure space (early FRP jetting, Fig 2b.) as well as in impulse space (jetting with accompanied longer duration accumulation). PEW Science postulates that the relatively expedient pressure decay previously described, further characterized by the expedient rarefaction-induced impulse decay in Figure 3, is responsible for the relatively trivial FRP impact. The silencer vents gas during all shots, quickly.
PEW Science Research Note 3: There exists a primary jet delay phenomenon after precursor flow, most easily discerned in the impulse regime in early time (Fig 3b). The delay occurs in all shots, relative to Shot 1, and it is only present upon primary jetting. PEW Science postulates this delay is due to flow dynamics between the interconnected baffles and annular cavities of the SLH300TI; more research is needed.
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 Sig Sauer SLH300TI is noticeably louder to bystanders than most silencers on this host weapon. Direct comparisons with other silencers are provided in Section 6.107.2.
6.107.1.2 SOUND SIGNATURES AT SHOOTER’S EAR
Real sound pressure histories from the same 5-shot test acquired with PEW-SOFT at the shooter’s ear are shown below. Again, the waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science testing is 1.0 MS/s (1 MHz).
The primary sound signature pressure histories at the ear for all 5 shots are shown in Figure 4. The primary sound signature history is shown on the left. A zoomed-in timescale is displayed on the right, in the region of peak sound pressure. The real sound impulse (momentum transfer potential) histories at the ear from the same 5-shot test are shown in Figure 5. Full and short timescales are shown.
Figure 4a. Sig Sauer SLH300TI Bolt Action 300 BLK Ear Sound Pressure Signature
Figure 4b. Sig Sauer SLH300TI Bolt Action 300 BLK Ear Sound Pressure Signature, Short Time Window
Figure 5a. Sig Sauer SLH300TI Bolt Action 300 BLK Ear Sound Impulse Signature
Figure 5b. Sig Sauer SLH300TI Bolt Action 300 BLK Ear Sound Impulse Signature
The severity of the FRP at the shooter’s ear with the Sig SLH300TI, relative to subsequent shots, is insignificant in accordance with PEW Science inner ear response analysis. This is similar to the phenomenon expressed in the muzzle signature to bystanders. Nonetheless, FRP is expressed in both the pressure regime (Figure 4b) and impulse regime (Figure 5).
The shooter’s ear suppression performance of the SLH300TI with subsonic 300 BLK ammunition on this host weapon is one of the most severe signatures produced by a full size silencer, tested by PEW Science, to date. This performance represents significant deviation from typical subsonic centerfire suppression with other full size silencers prevalent on the market. This suppression performance drop is postulated to be almost completely due to the high flow rate of the silencer and the manner in which it is achieved; relatively featureless annular vent cavities that exhaust to atmosphere at the distal end.
PEW Science Research Note 4: While the high flow rate of the SLH series may possibly prove favorable for the shooter on a semiautomatic weapon system, the pure suppression performance of the silencer is lower than typical. It is important to note that high flow rate designs typically have significantly reduced pure suppression performance with subsonic cartridges. As previously mentioned in this review, the overall performance of the SLH silencer is similar to that of the Surefire SOCOM762-RC2 on this platform; both silencers vent gas relatively quickly to atmosphere. But, unlike the Surefire silencer, the Sig silencer is intended to be used with subsonic 300 BLK. Surefire, instead, produces silencers like the SOCOM300-SPS for this purpose. As noted in the following section, the performance difference is significant.
As has been shown in PEW Science MK18 testing, as well as HK MP5 and P30L pistol testing, flow rate can influence the signature measured at the shooter’s ear, as mentioned above. However, it is important to note that significantly severe muzzle signature can still overwhelm the signature severity to the weapon operator, depending upon its total contribution to the signature. Semiautomatic 300 BLK testing will be performed by PEW Science in the future. PEW Science postulates that severe muzzle signatures generated on a bolt action rifle, in this combustion regime, still offer a window into performance potential on semiautomatic weapon systems.
Comparisons with other silencers in the subsonic flow regime are shown in Section 6.107.2, below.
6.107.2 Suppression Rating Comparison - Subsonic 300 BLK
The Sig Sauer SLH300TI was developed with a focus on sound reduction in the subsonic combustion regime (intended to exhibit a high PEW Science Suppression Rating) with a very high flow rate (low back pressure). As previously discussed, its subsonic sound signature suppression performance is relatively low for a full size rifle silencer. Figure 6 shows a performance comparison of the 18 .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
From the above data, it can be concluded that the Sig Sauer SLH300TI exhibits lower overall suppression performance in the subsonic 300 BLK combustion regime than most silencers presented in the PEW Science dataset, to date, especially compared to other full size rifle silencers. To bystanders, the 300 BLK signature suppression of the SLH300TI is on par with that from the Surefire SOCOM762-RC2 (Review 6.46); another full-size silencer that exhibits a relatively high flow rate. To the shooter, the SLH300TI is on-par in severity with the aforementioned Surefire silencer and the unwiped configuration of the Energetic Armament VOX S (Review 6.25) on this platform.
The Sig Sauer SLH300TI performs similarly to the Surefire SOCOM762-RC2 in this combustion regime, with a similar size, due to the purposeful high flow rate. Surefire, instead, produces the SOCOM300-SPS (Review 6.57) for this combustion regime. The SLH300TI performs similarly at the shooter’s ear to the Energetic Armament VOX S because the VOX S is relatively short, and its muzzle signature occurs in a closer proximity to the shooter. The additional standoff distance from the more severe muzzle blast of the SLH300TI, along with its relatively high flow rate, result in a sound field that provides a comparable signature severity to the shooter.
The Sig Sauer SLH300TI shares extremely similar internal geometric features with legacy Sig Sauer (and Q) silencer designs, as discussed previously in Section 6.107.1.1. The additional internal geometric features of the silencer, combined with the legacy features, are shown by this test data and analysis to be inefficient for sound signature reduction, for the length of the silencer. The goal of a higher flow rate, however, seems to have been achieved, as evidenced by the measured waveform features previously discussed.
The difference in sound signature performance from a silencer like the SLH300TI and other full size silencers like the Q Full Nelson (Review 6.99), CGS Hyperion (Review 6.71), or Otter Creek Labs Hydrogen-L (Review 6.94), is extremely significant. The user is encouraged to be mindful of the degree to which sound signature suppression, and resulting personnel hazards, can vary across designs. Small arm weapon system suppression performance is a spectrum. The PEW Science Suppression Rating and the Silencer Sound Standard help quantify this spectrum for end users and industry, objectively.
6.107.3 Review Summary: Sig Sauer SLH300TI 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 Sig Sauer SLH300TI achieved a Suppression Rating™ of 44.8 in PEW Science testing. As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.
PEW Science Subjective Opinion:
The Sig Sauer SLH300TI is a full size .30 rifle silencer with high flow rate (low back pressure), at the expense of suppression performance, with 300 BLK subsonic ammunition. Like some other rifle silencers, it is a direct-thread model possessing a 25-degree taper for use on tapered-barrel muzzles. The silencer can also attach to standard 90-degree shoulder muzzles due to adequate surface area at the mount interface. Other versions of the silencer exist that interface with Sig Sauer’s Clutch-LOK QD mounting system.
The Sig Sauer SLH300TI shares extremely similar internal geometric features with legacy Sig Sauer silencer designs such as with the Sig SRD762Ti-QD. The cone baffle design in the primary core of the silencer mirrors that of the legacy SRD series, as well as evolutions of that design from Q, such as in the Full Nelson, Half Nelson, Trash Panda, and Thunder Chicken.
However, in addition to the straight ported cones possessed by the SLH300TI, it also possesses outer annular cavities, exterior to the primary baffle geometry. This annulus is accessed through porting distributed throughout the outside edges of the baffle stack. The distal end of the silencer is vented; it is through this venting that the annular gas is exhausted to atmosphere. While this hybrid design shares similarities with various other 3D-printed designs from other manufactures like CGS in their Hyperion Technology and HUXWRX in their Flow-Through technology, it is considerably different in that the annular cavity exchanges pressure with the primary flow path in numerous locations. PEW Science postulates that this relatively simple design that combines annular flow with straight cones exhibits a relatively high flow rate at the expense of suppression performance; the test data and analysis in this report strongly supports this conclusion.
The Sig Sauer SLH300TI exhibits minimal first round pop (FRP) relative severity to bystanders and the shooter, on this host weapon platform. Users should keep in mind that the holistic signature is still relatively severe for the size of the silencer; the relative FRP performance notwithstanding.
The sound suppression performance of the SLH300TI on a semiautomatic weapon system, to the weapon operator, is most likely influenced favorably by the silencer’s high flow rate. However, it is also likely that the performance to the operator is unfavorably influenced by its severe muzzle signature in this combustion regime. Testing of the silencer on a semiautomatic host weapon platform with subsonic 300 BLK ammunition is the subject of future PEW Science research.
In this review, the Sig Sauer SLH300TI 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 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.
