SSS.6.39 - Sig Sauer SRD762Ti-QD and the Q mini FIX 300 BLK Subsonic (Free Version)
/Sig Sauer SRD762Ti-QD on a Q mini FIX 300 BLK with 8-in Barrel
The SRD762Ti-QD 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, including 300 Winchester Magnum. It has a 1.75-inch diameter and is 8.3 inches in length. The silencer mounts to a proprietary “Taper-Lok” muzzle brake or flash hider mount; the attachment of the silencer to the mount is facilitated by coarse threads behind a forward seating taper; there is also a secondary retention latch mechanism within the silencer body. The silencer is tubeless and constructed of Grade 5 titanium and the muzzle brake is constructed of stainless steel. The silencer and brake weigh 16.8 and 3.0 ounces, respectively, for a total system weight of 19.8 ounces, as tested. The SRD762Ti-QD can be obtained from Silencer Shop.
This review contains single-test results using the SRD762Ti-QD mounted with the Taper-Lok Muzzle Brake 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.
Summary: When paired with the Q mini FIX 8” 300 BLK and fired with Discreet Ballistics 190gr Subsonic Target ammunition, the Sig Sauer SRD762Ti-QD with Taper-Lok Muzzle Brake achieved a Suppression Rating™ of 68.2 in PEW Science testing.
Relative Suppression Rating Performance is Summarized in SSS.7 - PEW Science Rankings
6.39.1 SRD762Ti-QD Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the SRD762Ti-QD 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. Sig Sauer SRD762Ti-QD Sound Metric Summary
6.39.1.1 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 4-millisecond long sequence of events during the first test shot with the SRD762Ti-QD, as measured 1.0 m left of the muzzle. There are four significant events shown:
During combustion within the weapon system, a 118.6 dB peak is measured.
As the pressure pulse exits the silencer, an initial peak of 125.3 dB is measured.
Jetting increases out of the silencer end-cap, and a 133.4 dB peak occurs.
The maximum peak pressure amplitude of the first shot is measured to be 134.9 dB.
This is a somewhat atypical sequence observed when firing subsonic 300 BLK ammunition from a bolt-action weapon system with an attached silencer; the amplitude of the signature is relatively slow to increase, after projectile exit. Internal silencer design can significantly influence the measured timing and pressure amplitudes.
Fig. 1 Early-Time Shot History, Sig Sauer SRD762Ti-QD Bolt Action 300 BLK Muzzle Sound Pressure Signature, 20-MAR-2021
One distinguishing feature of the signature shown in Figure 1 is the delayed rise to a peak amplitude after the end-cap exit event and continued low threshold of peak amplitude in the overall signature. This is postulated to occur as a result of the length and baffle quantity of the SRD762Ti-QD. For comparison, the reader is encouraged to examine the subsonic 300 BLK test first round signatures of the Q Half Nelson in Sound Signature Review 6.29 and the Richmond Tactical RT30Ti in Sound Signature Review 6.35. Another notable difference between the early-time signature of the Sig Sauer SRD762Ti-QD and those two silencers with subsonic 300 BLK is the significantly lower amplitude immediately after the end-cap exit event with the SRD762Ti-QD. Overall subsonic 300 BLK performance comparisons of the three silencers are shown in Section 6.39.2 of this review.
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 SRD762Ti-QD Bolt Action 300 BLK Muzzle Sound Pressure Signature, 20-MAR-2021
Fig 2b. Sig Sauer SRD762Ti-QD Bolt Action 300 BLK Muzzle Sound Pressure Signature, Short Time Window, 20-MAR-2021
Figure 3a. Sig Sauer SRD762Ti-QD Bolt Action 300 BLK Muzzle Sound Impulse Signature, 20-MAR-2021
Figure 3b. Sig Sauer SRD762Ti-QD Bolt Action 300 BLK Muzzle Sound Impulse Signature, 20-MAR-2021
Figure 2 shows a slight pressure regime first-round-pop (FRP), in that Shot 2 does drop in peak amplitude, but Shot 3 exhibits the highest pressure at the muzzle of all shots. Regardless of the comparison of these peak pressure transients, Figure 3 shows a more exaggerated FRP in impulse space. The first round pop is postulated to be noticeable to bystanders, as determined by PEW Science inner-ear response analysis. However, it is interesting to note that although the FRP is noticeable, the overall magnitude of the FRP impulse with the SRD762Ti-QD is lower than the impulse of all shots with the Q Half Nelson; that is, the Half Nelson exhibits a sound signature at the muzzle that is always louder than that of the SRD762Ti-QD, and this conclusion is also evident in PEW Science inner ear modeling. These results are reasonable, given the similar designs of the silencers, and the shorter length and lower quantity of baffles in the the Half Nelson (4 less baffles than the SRD762Ti-QD). This comparison may help to illustrate sound suppression efficiency in the supersonic flow regime with the baffle type used in these silencers.
PEW Science Note 1: The impulse waveforms measured at the muzzle (Figure 3) are extremely consistent and of low amplitude; while the FRP waveform is noticeable in both impulse-space and PEW Science inner ear modeling, it is not nearly as severe as the waveforms measured with other silencers shown in public subsonic 300 BLK testing, to date.
PEW Science Note 2: 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, the SRD762Ti-QD is quieter to bystanders than all of the other silencers shown in public subsonic 300 BLK, to date. Direct comparisons are provided in Section 6.39.2, below. The FRP of all the silencers is noticeable to bystanders, with that of the SRD762Ti-QD being the least noticeable, by a significant margin. In-depth comparison of the sound signatures of these silencers with subsonic 300BLK is the subject of a future PEW Science Member Research Supplement.
6.39.2 Suppression Rating Comparison - Subsonic 300 BLK
The Sig Sauer SRD762Ti-QD suppressor is intended to possess high sound suppression performance. Figure 6 shows a performance comparison of the four .30 rifle silencers 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 Data 300 BLK Subsonic Test Data
Note that the performance of the SRD762Ti-QD at the weapon muzzle, which is an indicator of nearby bystander sound signature perception, is two full PEW Science Suppression Rating categories higher than that of both the Energetic Armament VOX S (Review 6.25) and Q Half Nelson (Review 6.29). At the shooter’s ear, the performance gap is also pronounced, with the at-ear Suppression Rating of the SRD762Ti-QD two Suppression Rating categories above that of the VOX S, and a category higher than that of the Half Nelson shooter’s ear Rating, on average. This indicates a significant difference in sound suppression between these silencers, to both the shooter and bystanders. It is also important to note that the difference in FRP signature between the SRD762Ti-QD and the other silencers with subsonic 300 BLK is noticeable, and the SRD762Ti-QD silencer has significantly quieter FRP to the shooter than does the RT30Ti or Half Nelson. In-depth FRP signature evaluations of these silencers in the subsonic flow regime is the subject of a future PEW Science Member Research Supplement. The Resonator K and VOX S are objectively louder silencers. Bolt-action host weapon testing allows strict isolation of sound suppression performance variables.
It is very important to note, again, that the SRD762Ti-QD possesses 13 baffles, whereas the Q Half Nelson is smaller and possesses 9 baffles of very similar type. In the subsonic flow suppression regime, overall silencer size, volume, and baffle quantity, can significantly influence sound suppression performance. The degree to which the performance is influenced by these variables depends on not only the flow regime, but the silencer baffle design.
6.39.3 Review Summary: Sig Sauer SRD762Ti-QD 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 SRD762Ti-QD with Taper-Lok Muzzle Brake achieved a Suppression Rating™ of 68.2 in PEW Science testing.
PEW Science Subjective Opinion:
The Sig Sauer SRD762Ti-QD is a relatively light weight, tubeless, and full-size centerfire rifle silencer with a 1.75-inch diameter that exhibits high sound suppression performance in the subsonic flow regime. The silencer possesses a proprietary taper mount system with secondary latch retention; a popular feature set that has benefits for both accuracy and convenience.
The SRD762Ti-QD contains thirteen baffles. The baffles are ported and notched straight cones, circumferentially welded, forming the “tubeless” body. This is very similar to the silencers from Q tested by PEW Science. Although the silencer is not new to the market, the subsonic suppression performance is high and extremely competitive with many new current offerings. Supersonic suppression performance evaluation of the SRD762Ti-QD is the subject of future PEW Science publication.
The silencer is offered in both steel and titanium versions; the titanium version of the silencer was tested by PEW Science, and mounted with the proprietary Sig Sauer Taper-Lok muzzle brake on the Q mini FIX 300 BLK host; this mount is somewhat similar to others now on the market, in that it has coarse threads that are isolated from fouling by a forward seating taper. A notable feature of the mount is that the tapered surface is significantly larger than several QD/taper implementations on silencer mounts from other manufacturers. Additional features of this mount that are different than some others on the market include a secondary retention latch, a taper on the muzzle thread interface (to facilitate taper mounting with tapered muzzles, with backward compatibility for 90-deg shoulders), functional brake porting, and rear wrench flats for installation/removal on the host weapon.
The secondary retention latch of the silencer may be viewed as almost superfluous, in that the primary mechanism of retention is the friction-lock facilitated by the seating taper interface normal force created from coarse thread engagement. The silencer may become difficult to remove, even without the secondary latch retention. With proper muzzle device installation on the host weapon, this is not postulated to be an issue for most users; however, to facilitate quick removal in the field, a strap wrench may be needed. Note that if the mount were to remain in the silencer upon silencer removal from the host weapon, as a result of improper muzzle device installation on the host weapon, the wrench flats on the rear of the muzzle device may be used to remove the muzzle device from the silencer at a later time. This may be an attractive feature to some users.
First round pop (FRP) in the subsonic flow regime continues to be a significant phenomenon observed by PEW Science. The SRD762Ti-QD is observed to address it better than many silencers. It is important to note that the subsonic 300 BLK cartridge is intended to excel at highly reduced sound signature. Users primarily concerned with sound signature suppression on this platform should know that FRP can be a significant performance factor.
In this review, the SRD762Ti-QD 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.
