SIG SAUER Suppressors: Surpassing All Expectations

By Todd Burgreen

SIG SAUER has become a true “one-stop shop” for military, law enforcement and civilian operators. The SIG SAUER Silencer Division was formally created in 2014 with its major introduction to the shooting public taking place at the 2015 SHOT Show. SIG SAUER had earlier entered the suppressor market, but decided a formal distinct division headed by industry veterans Kevin Brittingham, founder of AAC, and Ethan Lessard would be the better path. Suppressor use has never been as popular for military, law enforcement and civilians. The benefits of suppressor use are hard to argue against.

This article will convey SIG’s commitment to improving suppressors across the board in terms of sound reduction, muzzle flash, durability, accuracy, mounting method, accuracy etc. While sounding ambitious, this will be accomplished by highlighting multiple models such as the SRD22, SRD556-QD, SRD762-QD and SRD45. SIG SAUER did not seek to mimic other suppressor designs; instead they chose their own path backed by engineering, experience and science.

Each type of SIG SAUER suppressor, albeit rimfire, pistol, rifle, has unique characteristics distinguishing it from competitor cans. The SIG SAUER SRD22 22LR Silencer features an aluminum outer tube with stainless steel baffles. The SRD22 measures 6.2 inches long, 1.25 inches in diameter and weighs 7.7 ounces. SIG SAUER lists sound signature reduction down to 117 decibels (db) with the SRD22. For reference sake, the actions of many semiautomatic .22 caliber weapons produce 125-130 decibels when cycling out and into battery. An unsuppressed .22LR produces approximately 142 decibels when fired. Unsuppressed centerfire rifles and handguns produce approximately 165 decibels. The SRD22 comes with both ½”x 28 tpi and M9 x.75 adaptors to facilitate mounting to typical US and European thread patterns found on 22LR weapons.

The SRD22 suppressor is easily disassembled for cleaning. This is especially important with a 22LR suppressor versus other calibers due to the preponderance use of lead in 22LR ammunition. SIG SAUER provides a tool that matches the end cap notches of the SRD22 facilitating easy removal. After removing the end cap the stacked stainless steel baffles are emptied out simplifying cleaning. The baffles are then inserted back into the aluminum shroud and end cap screwed back into place. The removal and reinsertion of the baffles are intuitive with little concern warranted for doing them incorrectly. I say this as some 22LR suppressors on the market are not. This encourages proper maintenance routines to be followed with the SIG SAUER SRD22 keeping it operating at a maximum efficiency suppressing sound signature.

It seemed fitting to combine the SIG SAUER suppressor with a SIG SAUER 1911-22 pistol. This was easy to do as the 1911-22 has a threaded barrel easily adaptable to using a suppressor. While usable with both rifles and handguns, the SIG SAUER SRD22 suppressor is ideal for use with handguns.

This rests with the minimal barrel length associated with handguns helping to maximize how 22LR ammunition can be used while maintaining subsonic velocities. 1,050 feet per second and under is a good rule of thumb for subsonic velocities. The difference in noise produced from firing supersonic ammunition, which generates a distinct “crack” due to exceeding the sound barrier, versus subsonic through a suppressor is striking.

Experimentation with different loads is encouraged and can yield surprising results. Often Match or Standard velocity 22LR ammunition proves subsonic when fired from a pistol length barrel compared to when fired from a 16 inch rifle barrel. Another reason for casting a wide net is to determine what subsonic loads still function reliably with the blowback operating method typical of rimfire weapons such as the SIG SAUER 1911-22. The evaluation of different ammunition is important to conduct with and without the suppressor mounted no matter what caliber is involved.

A mounted SIG SAUER SRD22 suppressor reinforces all of the positive characteristics of using a 22LR handgun--zero recoil, no muzzle signature—for increased practice proficiency. The SRD22 suppressed SIG SAUER 1911-22 combo does everything a 22LR should do such as providing solid accuracy and reliable semi-automatic fire for enhancing marksmanship capabilities in shooters of all skill levels. The SIG SAUER SRD22 can easily be used with any threaded 22LR platform albeit handgun or rifle. The SIG SAUER SRD22 provides the closest equivalent to “movie quiet” expectations. No other suppressor caliber combination is as quiet as a properly suppressed 22LR.

The SRD45 .45AUTO pistol silencer features a Grade 9 titanium tube and 17-4PH stainless steel baffles allowing for light weight and durability. The SRD45 features a booster for use with Browning Tilting Barrel-type pistols. A fixed barrel spacer is also available for use with fixed-barrel hosts like the SIG MPX.

The SRD45 ships with both .578-28tpi and M16x1mm LH pistons. SIG SAUER pistol silencers feature 21 points of adjustment allowing you to time the projectile’s point of impact to match the pistol without a silencer maintaining the weapon’s sight zero.

The SRD45’s overall length is 7.9 inches with a diameter of 1.38 inches and weighs only 12 ounces while offering a 133db sound rating. Initial range time consisted of testing the SRD45 to verify that established accuracy and reliability parameters of host handguns were not compromised. The booster system allows the suppressor to be adapted to most semi-automatic handguns, even with the Browning short recoil system were the barrel moves, for flawless functioning. The SIG booster design allows one suppressor to fit on almost any type of pistol by simply purchasing the correct adaptor. The SRD45 utilizes stainless steel baffles to minimize corrosion and titanium tube to minimize weight. The SRD45’s baffle stack is not only optimized for a sound reduction but also designed to come apart allowing for cleaning.

It does not take a drastic imagination leap to visualize what roles a handgun or SMG fitted with a SIG SAUER SRD45 would fill. Anything from sentry removal, canine or other, and CQB operations indoors come to mind. Not to be underestimated is the ability to target shoot with minimal noise, flash and blast. Suppressors are the most efficient muzzle brakes available. The SRD45 was mounted on a SIG MPX as well as Kriss Vector. Also used was a GLOCK 21.

The SIG SAUER difference really shines through when we move to discussing rifle suppressors. Through a revolutionary baffle design and unique manufacturing processes, SIG SAUER has eliminated the outer tube shell found in other rifle silencers. SIG SAUER utilizes 100-percent circumferential welds combined with wire electronic discharge machining (EDM) the pathway of the projectile.

In addition to reducing weight, this tubeless design increases volume, lowering pressure and temperature for greater durability and increased signature reduction. Each of these benefits sets apart SIG SAUER suppressors. SIG does not stop here.

SIG further pushes the envelope using the best metals and coatings (physical vapor deposition-PVD-finish) combined with superior mounting methods—either direct thread or quick detach. PVD is more resistant to heat as well as scratch resistant. Inconel 718 (mixture of stainless steel and nickel alloy) is used to withstand the punishment of mounting suppressors to short-barreled rifles and high round counts. Titanium is also offered as an option for users requiring even more weight shaving from their suppressors.

For SIG’s rifle suppressors, a Taper-Lok Fast-Attach System was created, enabling quick and simple installation of a muzzle adapter device, which eliminates the need for shims.

The SIG SAUER design optimizes alignment, improving accuracy and greatly reducing point-of-impact (POI) shift, even after multiple install/removal cycles. The Taper-Lok system allows users to access a variety of muzzle brakes and flash hiders for their rifles; all the while enabling SIG rifle suppressors to attach when needed. The Taper-Lok Fast-Attach System reduces point of impact shift and increases repeatability by centering the silencer during installation. SIG’s Taper-Lok design eliminates tolerance stacking, resulting in some of the most secure, reliable and accurate rifle mounts available. The SIG design tapers on key surfaces providing self-centering for accuracy. All SIG muzzle devices and silencers are backwards compatible to traditional 90 degree shouldered firearms found outside the SIG weapon line up. Hand pressure is all that is needed to secure or remove the SIG suppressor. Silencer removal requires 20 percent more force than attachment, preventing any loosening during shooting. The Taper-Lok system contributes to the adaptability of the SIG rifle suppressors to more than one platform. By investing in multiple Taper-Lok muzzle devices, the user can move the suppressor between different rifles.

The SRD556-QD weighs 14 ounces and measures 6.5 inches with a width of 1.625 inches offering a sound rating of 134db. The tail of the tape for SRD762-QD is 17 ounces, 7 inches long, 1.625 wide and has a sound rating of 140db.

The SRD762-QD is rated for .300WinMag usage. Another offered capability is to use a SRD762 suppressor on a 5.56 mm chambered weapon. Basically, if the bullet diameter is .30 caliber or less the SRD762-QD can be used—of course, verify with SIG SAUER if any “exotic” calibers or applications are being contemplated. The limiting factor is getting the Taper-Lok muzzle device mounted to your barrel. The SIG SAUER Taper-Lok is not only an ingenious mounting system for the suppressor body but also an effective flash hider or muzzle device in it own right.

The SIG SAUER rifle suppressors were mounted and tested on a variety of weapon platforms consisting of SIG SAUER MCX, 516 SBR and 716 Patrol. It was as simple as installing a Taper-Lok muzzle device adapter on each weapon.

Conversations with multiple operational entities indicate that most of their rifle sound suppressor use does not involve subsonic ammunition. The loss in terms of ballistic capability combined with the cost of specialized subsonic rifle ammunition and difficulty of finding quality sub-sonic ammunition being the root reasons. Many users feel the suppressor’s ability to minimize muzzle blast is well worth using it even though the prominent sonic crack is still present when using standard supersonic ammunition.

Range experience was rather subjective in evaluating the SIG SAUER suppressors’ raison d’être—ability to lessen or dampen noise. No high tech auditory monitoring gear was used; just expectations based on previous experiences along with suppressors from other manufacturers on hand for direct comparison with ammunition from the same lot# being fired out of multiple suppressors. The more one studies suppressors as a subject matter the more one realizes even with the audio equipment there are many variables in getting an accurate db reduction reading, i.e. atmospheric conditions, installation method of the suppressor, type of weapon used and first round pop phenomenon (FRP), etc.

The SIG SAUER suppressors were tested over an extended period of time consisting of numerous range visits.

The advantage of the Taper-Lok QD method became quickly apparent and appreciated as the suppressors were shifted between the different rifles.

The individual weapon’s point of impact (POI) did shift when the suppressor was installed. This is to be expected whenever hanging something off the end of a rifle barrel.

It changes the barrel’s harmonics. What was closely monitored was whether the point of impact stayed consistent once logged in when the suppressor was installed on a specific rifle. Another important consideration for a suppressor is if the accuracy of a rifle is impacted negatively. This is important if long range work is considered with standard “supersonic” ammunition.

It is quite interesting to be sitting or lying behind a berm as rounds pass overhead. This was done to both get an idea of how effective the SIG suppressors were in reducing the sound of a round fired and masking the location of the shot. While this may strike many as unsafe or irresponsible, it was managed as closely as possible to ensure safety. It was no different than working the target pits at a rifle competition. The supersonic rounds were clearly audible, but the SIG rifle suppressor’s ability to mask the normal muzzle blast signature made identifying where the shot came from more problematic. This is further enhanced the farther away the shooter is from the target. The SIG SRD22 and SRD45 were eerily quiet due to subsonic ammunition being the norm. The subsonic rounds were very impressive in this range test format. The sound of a round striking a steel target near your position with no prior warning is eerily impressive. The SIG suppressors were also analyzed when standing next to a weapon firing. The use of hearing protection was not needed, especially with subsonic ammunition.

Actual sound reduction differences between most respected suppressors are small. More important is durability, especially if high volume firing is expected. Maintaining zero and accuracy when installed, removed and then reinstalled is paramount. Along these same lines many will find that the flexibility of moving a suppressor between platforms is highly appreciated while maintaining all of the above listed characteristics. The SIG SAUER suppressors succeed in surpassing all expectations no matter the criteria used to judge: sound reduction, durability, accuracy and flexibility. This is a credit to their design and real-world experience found in the SIG SAUER Silencer Division team.

This article first appeared in Small Arms Review V21N4 (May 2017)
and was posted online on March 17, 2017


Comments have not been generated for this article.