Operator Suppressor Systems

OSS introduces the Next Generation of Firearms Sound Suppression.

Like most of you, I enjoy kick-ass action movies. It is not uncommon to see classic James Bond or modern day Jason Bourne creeping up on some unsuspecting bad guy then eliminating him with a quick triple tap, where only the gentle “pfftt, pfftt, pfftt” is heard from their sound suppressed pistol. Or maybe they need to engage a target at distance with some high-speed, low-drag break-down rifle they piece together out of an unassuming backpack. They make it look so easy and effortless. Of course the last step is to attach the sleek silencer before taking out the offending character with a slight “puff” from the suppressed rifle.

Despite how Hollywood depicts Silencers in the movies, it is damn near impossible to completely eliminate the sound that is made when a projectile is launched out of a firearm at extremely high speeds. “Did he just say silencer!? How dare he!? Blasphemy!” Yes, I know the proper term is “Sound Suppressor” however when the first firearm muffler was designed by American Inventor, Hiram Percy Maxim, back in 1902, it was called the Maxim Silencer. Sound Suppressors are also commonly called Silencers by manufactures and consumers alike. That being said, “Sound Suppressor” is the more accurate term as the device can’t completely “Silence” the sounds made by the firing process. The term “Sound Muffler” would also be appropriate. All things considered, I think it is safe to say, “Silencer” when referring to a Sound Suppressor if you so choose, but I’ll be damned if I ever call a magazine a clip. That just ain’t right.

Firearm Sound Suppression

There are a handful of sounds produced when a firearm is discharged. First, there is the detonation of the bullet primer as it is struck by the firing pin. I suppose this could be lumped in with the mechanical operation; however the bullet components aren’t technically part of the actual firearm. Second, there is the mechanical operation of the firearm as the parts move during the firing cycle. Next is the sound of the muzzle blast as the hot gasses explode out of the muzzle, propelling the bullet towards the target. Following the muzzle blast is the supersonic crack of the bullet as it breaks the sound barrier. Lastly, however slight it may be, there is the sound of the bullet impact as it hits its mark.

Suppressors work to mitigate the sound caused by the muzzle blast. In order to do this, a sound suppressor must slow and control the otherwise rapid and violent explosion of gasses leaving the muzzle. Traditional suppressors even to this day are typically a round tube in which a series of expansion chambers are stacked. These chambers are separated by baffles which are basically metal spacers with holes in the middle that allow the bullet to pass through. Think washers. Once the bullet passes a baffle the gasses behind the round enter the chamber and then expand, cool and release at a slower, more controlled rate. The result is a reduced audible sound and explosion as the bullet leaves the barrel. As a bonus, a sound suppressor also does an excellent job in reducing if not eliminating the firearm flash signature. Between the noise reduction and the flash suppression, it makes shooting at night and in confined spaces, such as a home or vehicle, more tolerable. It is also very difficult to determine the direction of where a shot is fired from. This has obvious advantages on the battlefield.

Pay to Play

As cool as sound suppressors appear in the movies, Hollywood doesn’t address their negative attributes. The first issue is blowback. Anyone who has ever shot a suppressed, semi-automatic or fully automatic firearm has experienced blowback. Blowback is when gasses and carbon are ejected into the face of the shooter during suppressed fire. Remember, the silencer slows the rate of gas expansion prior to expulsion. This means the gas stacks up in the barrel waiting its turn to be expelled from the suppressor. As the gases in the barrel wait to be expelled, pressures are increased to a higher psi than the firearm was originally designed for. This affects the timing of the gun. On a suppressed firearm, the bolt unlocks prematurely and begins to extract the fired casing from the chamber. The seal the spent casing created at the rear of the barrel is subsequently broken. The pressurized gas that is still stacked in the barrel will then take the path of least resistance relieving itself into the receiver of the firearm, out the ejection port and into the shooters face. This is very annoying and over time can make for a very unpleasant shooting experience. The gasses will burn the eyes and throat and obscure the target. None of which are good things especially when on a two way range.

Some of the blowback can be alleviated on many semi-auto rifles by using adjustable gas blocks. The additional pressure increase also expedites wear and tear on the moving parts of the firearm by increasing its cyclical rate of fire or bolt velocity. This increased movement can be exasperated by a number of factors to include the barrel length, type of operating system and rate of fire. The result is that parts which play a critical role in the firearm operation are subject to excessive heat, gas and carbon. This increases part failure risk and reduces part life span. Neither of which are good.

Then there is the perceived sound to consider. I will often see the keyboard commandos break bad with their “skillz” when they see someone shooting a sound suppressed weapon with ear protection on. “Hey bro, why the ear pro? Do you even sound suppress?” Because it still effing hurts the ears, that’s why. “What you say!?” Yes, despite what the movies would have you believe, not all sound suppressors can reduce all calibers of ammunition, in every firearm down to “ear safe” or pain free levels. They will take the edge off for sure, but I have shot many suppressed rifles that have left my ears ringing.

Back to School

What constitutes as being a harmful noise? One that is painful to listen to? Or maybe one that is just constant over long period of time? The answer is both. Sound is measured in decibels (dB) and is used to assign value to sound levels. Higher levels of sound over a longer period of time will begin to destroy the stereocilia in the ear. These are the very fine hair-like structures in the ear that move within a sound wave and send electronic signals to the brain to be registered. Once damaged or destroyed, they cannot be repaired and will result in hearing damage and/or loss. Let’s put it this way; a typical conversation can reach around 60 decibels or so assuming yelling is not involved. 60 dB is not a harmful level of sound. I once had an acoustics engineer inform me that she wears ear pro when around sounds in excess of 85 dB. She told me sounds at that level will begin to damage human hearing after prolonged exposure. The U.S. Department of Health and Human Services confirms what she said.

An unsuppressed firearm will have a decibel rating between 140 dB and 190 dB or so. Obviously the perceived decibel reading will depend on a bunch of different variables such as type of the round and the proximity of the blast, space confines, where the sound is measured at, etc. Regardless, these types of decibel ratings can damage hearing immediately and permanently even after one shot. I am proof of this. As I write this I can hear the constant ringing in my ears, also known as tinnitus, that I have had since suffering hearing damage during my time in the military.

The Occupational Safety and Health Administration, otherwise known as OSHA, governs safety protocol within the workplace. They even dictate how long a person should be exposed to certain levels of sounds within a work environment. OSHA notes that 140 dB is the threshold of pain, which is the low range for a firearm discharge. For us shooters, one of the goals of a sound suppressor is to reduce the decibel levels generated by a firearm below the threshold of pain or sub 140 dB. This is what is often referred to as “ear safe” because it isn’t painful, but as we now know, anything above 85 dB can damage hearing. OSHA even recommends “that all worker exposures to noise should be controlled below a level equivalent to 85 dB for eight hours to minimize occupational noise induced hearing loss.”

Time for Change

“Ok Professor, enough with the lecture. Get back to the high-speed, low-drag, tacti-cool stuff.” Fine. From experience we all know loud noise hurts the ears. We also know, by the very nature of how we are designed, the human body will naturally recoil away from loud sounds, fast moving objects and bright flashes of light. Despite their drawbacks, sound suppressors help mitigate two out of those three natural triggers which in turn makes them desirable when shooting a firearm from the shooters perspective. It should be noted there are other ways to further reduce the other related sounds the suppressor cannot affect such as the mechanical engineering of the firearm or using a subsonic round.

While not all suppressors are 1.5-inch cylindrical tubes, the majority traditionally are. It makes for a simpler product to engineer and manufacture. Sure each suppressor company has their own spin on the shape of their baffle, the length or girth of the “can” and the size of the expansion chambers or the materials used. There are a lot of great suppressor companies out there with proven track records and I am a fan of many, but they all share very similar and traditional expansion chamber technology which is over a century old. There is one company, however, that is breaking out of the traditional silencer mold. Operators Suppressor Systems, also known as OSS Mission, has developed a revolutionary new sound suppressor system that is changing the suppressor market as we know it.

Going Hands On

The first time I laid my hands on an OSS Mission Sound Suppressor was at Media Day, SHOT Show 2014. In fact, I wasn’t even looking for OSS; rather I was looking for Heckler and Koch. After waiting in a long and somewhat disorganized line it was my turn to send a few rounds down range with HK. HK had a few items to sample, one of which was the unveiling of their new MR556A1-SD. This MR556A1-SD is an AR type rifle that utilizes the technologies found on the military HK 416. It is unique in that it incorporates the OSS Mission Sound Suppressor and the new HK Modular Rail System or MRS. I had the opportunity to engage a handful of targets at different ranges with a couple of magazines. It was a very enjoyable experience and while I couldn’t appreciate the sound suppression due to all the fireworks that were going off at the other manufacture booths, I walked away with a big smile on my face. The OSS equipped MR556A1-SD was a well-balanced, soft shooting rifle. It was a pleasure to shoot and I didn’t walk away with a face full of gas. The OSS did an outstanding job of mitigating blowback.

After my very brief affair that left me longing for more, I was intercepted by a very enthusiastic OSS rep. He asked me what I thought and I gave him a very brief after action report that basically said, “It was fu$%ing awesome!” He smiled and asked me if I was interested in learning more about the OSS technology. Of course I was. So he took the time to show me a 3D cut out of a standard sound suppressor and go over much of the same information I mentioned at the beginning of the article. Next, he broke down the OSS suppressor to go over the naughty bits. In a few quick twists he had the suppressor apart into five different pieces. I must admit, I wasn’t quite sure what I was looking at. There were no baffles or expansion chambers to be found anywhere. Rather the guts of the suppressor looked more like the inside of a jet engine or turbine. Okay, someone had some ‘splaining to do.

The System

The five components I was looking at make up the entire system, which are designed to be used with a specific caliber, yet some parts can be converted for use on multiple calibers. The odd, turbine looking part is the host assembly known as the Flash Hider Muzzle Brake or FHMB. This is the part that attaches over the barrel and acts as part of the Back Pressure Regulator and as an effective muzzle brake. The FHMB separates into two pieces and is designed to stay fixed to the host rifle. It should be noted, while the components are easily removable, I would not classify the OSS Mission Suppressor as a quick detach suppressor system. The FHMB can be purchased in different calibers ranging from 5.56 through 7.62. For shooters using barrels just under 16 inches the FHMB can be permanently attached, bringing the shorter barrel into legal compliance (depending on barrel length of course). The outer most brake on the FHMB can be pinned, however it cannot be welded. The pin must pass through the cage into the locking block, through the edge of the barrel, through the locking block again and out the other side. If this is something you are interested in, please consult a competent gunsmith who is very familiar with the OSS system. You don’t want to risk damaging the suppressor system or violating any SBR laws.

Next is the exterior housing, which is octagonal in section. Once installed over the FHMB it completes the Back Pressure Regular or BPR. The BPRs controls the expanding gasses and eliminates 95% of the back pressure that is normal with traditional baffled suppressors. It lowers the dB rating some extent; however, this is not the ear safe component of the suppressor system. The BPR has a self-tightening feature which makes it impossible to loosen the BPR through normal shooting. There are two types of BPRs. The first, known as the BPR1, is meant for over the barrel applications. As the end of the BPR stops at the end of the FHMB, which is attached to the end of the barrel, the length of the rifle is only increased by .63-inches (before the SRM is attached). However, you will need about 4.25-inches of exposed, uninterrupted barrel length in order for the FHMB to slide over. If barrel length is scarce, the BPR2 is available for a flush mount on a short barreled rifle or AR pistol. This system increases the overall length of the rifle by 7.25-inches (before the SRM is attached).

The BPR system mates with the FHMB and reduces back pressure, excessive mechanical wear, rate of fire, thermal signature and decibel output. Reduced mechanical wear is huge. Traditional suppressors can increase the cyclical rate of a firearm substantially. For example the bolt velocity increase on the HK MR556 with a traditional suppressor installed is around 30% to 40%. This results in a hot, dirty and torturous environment for the firearm internals, pushing or exceeding the design limits. The same MR556 with the OSS suppressor installed has a bolt velocity increase of a mere 6%! It is very noticeable and very welcomed. This is achieved by the gas flowing through and around the “turbine” fins or coils. This means the gas never stops moving and is released out of the front of the suppressor, eliminating most of the high pressure build up found in traditional suppressors.

The octagonal shape of the suppressor housing works to disperses the mirage signature that is generated during rapid strings of fire. Instead of the heat working its way to the highest tangent of the cylinder then rising as a concentrated signature, it is dispersed over the flat surface of the octagon. OSS claims this results in a 60% reduction of line-of-sight mirage signature. This is good for the shooter as it maintains a clearer sight picture and doesn’t give away position.

Next in line is the Signature Reduction Module or SRM. This is attached onto the BPR, adding an additional 4.2-inches to the length of the weapon system. This unit is a three-part system that reduce sound and visual signature. The SRM must be used in line with the BPR and cannot be used as a stand-alone system. It is installed in three stages. First the octagonal housing must be attached to the BPR, but not tightened all the way. Next the core, which look very similar to the FHMB is dropped in and turned until it is keyed to the end of the FHMB. Lastly, the end cap is screwed on and the octagonal housing is then tightened until it is aligned with the housing of the BPR.

Thanks to the keying feature on the FHMB, the SRM core is installed in the exact same place every time. This consistent timing, results in minimal shift in bullet impact. OSS claims the maximum shift to be .5 MOA, however I have yet to verify that at the time of this writing. As the name implies, the unit reduces visual and audible signatures. The goal is to get the decibels below the pain threshold of 140 dB. OSS was able to meet that goal with both the BPR and SRM installed and achieved a level of 138 dB. OSS takes all their measurements at the shooters right ear. When shooting my personal OSS Mission Sound suppressor (yes, I had to buy one), I found I was able to shoot my 5.56 AR type rifles without ear protection. The SRM also does a great job of reducing visual signature. OSS states, “Most suppressors in the market have a first round flash of 300.0 Lux in compared to 3.0 Lux on the OSS Suppressor.” As noted above, this is highly important on the battlefield as it is much harder to pinpoint where shots are coming from if the muzzle flash is not visible from the targets perspective.

It should be noted the OSS suppressor system is a bit wider in diameter than the 1.5 inch width found on most traditional suppressors. OSS states the maximum outside diameter is 1.752-inches. If you want to buy a rail system that will surround the suppressor make sure the inside diameter is appropriate. Seekins Precision MCSR v2 works well as it has an inside diameter of 1.8-inches as does the Radical Firearms/Seekins Rail. OSS also makes their own 13-inch long and 15-inch long rail system which is available through their dealer network. Lastly, if there is a specific mission profile that requires exact decibel reduction, size, barrel length and caliber, OSS offers their Combined Technology Unit or CTU. This is a made to order system that is tuned to the end user’s weapons platform. The end user will need to contact OSS directly to specify their design and order.

Blood, Sweat & Tears

So now that we know a little bit about this new technology, how reliable is it and what is the backstory? I mean OSS is the new kid on the proverbial block, right? Let’s not jump to conclusions just yet. I had the opportunity to get a lot of Q & A time with OSS founder and inventor, Russell Oliver. Russell didn’t create this new found technology over-night; rather it came to him the hard way.

Russ has been designing sound suppressors for 21 years. In fact he obtained his FFL a mere two weeks after his 21st birthday. During his 20s and early 30s he owned a number of retail stores, was a sales rep for Heckler and Koch, ran a law enforcement training firm and worked as a private contractor. At the ripe old age of 32 he joined Uncle Sam’s Army. By age 34 he was on the Special Forces track and went on to spend eight years as a Green Beret. He has worked with numerous organizations during and after his time in the Army to include: U.S. Army Special forces command, USSOCOM weapons development, USSOCOM science and technology suppression, NSWC Crane and many more. Russell started OSS during his time at the Special Forces Qualification Course, also known as Q Course, which is headquartered out of Ft. Bragg. The first designs were drawn up at that time and continue to evolve to this day. Today the OSS 18,000 square foot state-of-the-art manufacturing and research facility is currently based out of Murray, Utah.

Science, Not Bullshit

Looking at their website the specifications listed for the current system are fairly impressive. Needless to say I am somewhat of a skeptic. Manufactures inflate their statistics all the time to increase perceived performance and increased sales. I am not saying they lie, rather they may not disclose all the test conditions and results. I flat out asked Russell if this was the case.

He told me “the maintenance and round counts [OSS] mention on the website are actually the most pessimistic of numbers and [OSS] will actually be raising them substantially shortly… This […] flies in the face of industry standards… we only print the worst case scenario numbers.”

I pushed further and asked if the results are based off a computer simulation or actual physical tests. His response was very candid.

He stated: “These accounts have been verified multiple times with multiple grain projectiles, ammunition manufactures, barrel lengths and operating systems. There is no way to computer simulate accurately the actual wear and tear of heat and pressure on which ever metal is utilized. We currently sell what is internally referred to as the generation 4 design… [We have a] generation 2 system that has well over 130,000 rounds. It began its life at about 138 dB with XM193 ammunition out of a M4 barrel. 130,000 rounds later and significant inside diameter erosion it runs at about 142 dB.”

He continued to inform me about suppressor sustainment in relation to performance degradation.

“Our sustainment numbers are based upon the military sustainment model of optimal performance. For example look at the M4 barrel. Its sustainment life is 20,000 rounds, that does not mean that you cannot shoot 200,000 rounds through the barrel. It means that optimal accuracy begins to erode at 20,000 rounds. Like a barrel the OSS deflectors erode over time. However, accuracy is not lost, decibel reduction is lost as the inside diameter begins to open due to erosion. There is no failure; there is […] overall decibel reduction.”

It is obvious Russell is extremely passionate about the evolutionary process the OSS suppressors have been through. He went on to elaborate on the OSS testing process:

“The extent of testing is millions of rounds. Most people think that OSS has been around a year or two. [In actuality] the system has been in development for over six years after a previous 15 years of making washers in a tube like everyone else, four of which we generally hid from the civilian market intentionally. The gun world is skeptical enough as is, full of emotional opinions unrelated to the actual science involved in weapons systems and suppression. This technology and its modular sustainable design asks the user not to take one step forward but several steps forward at the same time. Inevitably it’s a lot to ask in an industry based largely on tradition. Not necessarily a bad thing but making it very difficult to introduce new ideas. We concentrated on developing for the special operations end-user, not marketing to the civilian market. I am very comfortable in saying that the water, mud, freeze, heat, round count, etc. completed by OSS, independent units, and OEMs from multiple manufacturers, far exceeds most any suppressor made. Consider we developed for four years without selling a device, how much testing can be done in four years? A lot! The OSS suppressor utilizes what DOE engineers refer to as flow-through suppression. This flow-through design [allows for a] greater volume […] of expanding gases [to exit] the suppressor. One of the beneficial effects of this greater […] volume is a two thirds reduction in the drain time required before firing a fully submerged suppressor. The OSS drain time is less than one second as a result. Another benefit of flow-through is a reduced operating pressure of the suppressor itself and a significant reduction in operating temperature. The OSS suppressor runs at approximately 1/3 the PSI of any standard baffle design. If you combine the reduction of two thirds pressure and 1/2 to 1/3 operating temperature you exponentially increase the life expectancy of any metal. When I say 130,000 rounds through a 5.56 M4 suppressor the performance is based upon science not bullshit. Any metallurgist will tell you if you reduce the operating temperature and pressure by such a degree you increase the duration of structural integrity by multiples of 10 in the most pessimistic of calculations.”

I also asked Russ about the testing HK put the OSS through prior to selecting it as their sponsored sound suppressor, but due to confidentiality and a signed non-disclosure agreement, Russell could not legally elaborate. That being said, HK spent more than 2 years and over a half a million dollars in testing. I’ll leave that one right there for contemplation.

OSS suppressors have gone through an intricate fabrication process. When the system is taken apart and all of its components are on display this becomes very evident.

Russell explains the machining process

“Most of the components in the OSS system are five axis CNC machined out of solid rod material in-house. [… ] Unlike most machining, the inside texture of the flutes, coils, and or turbines are not intended to be smooth. […] When you think of the physics applied in energy absorption, surface area is paramount. Add that into the duration of time [the gas takes] to exit […] the turbines, the added resistance of uneven services results in additional decibel reduction. Simply put, a rippled surface increases the surface area and the turbulence. Both of these aspects increase energy transfer and absorption within the system. If you examine the other components of the suppressor, it is obvious that we can certainly manufacturer incredibly smooth polished precise components when the intent of that component requires a high level of accuracy and limited resistance. In the end we are only talking about one quarter to one half decibel reduction over the entire device. Relatively irrelevant by itself, but when added to other fine-tuning aspects they all add up. In addition to the physical benefits of an uneven surface, […] from the machining aspect finish passes and finish cutting is not required on these components.”

It is evident to this author that OSS really hit on something special. I can confidently say this as a writer and a consumer. As mentioned before, I personally own an OSS suppressor that is designed for the 5.56 round. It currently is attached to my Faxon Firearms ARAK-21 build with a 16 inch barrel. I will be purchasing more FHMBs for my other rifles in the future. The OSS technology makes shooting a suppressed firearm for prolonged periods of time an absolute pleasure. I currently have about 500 rounds through mine, which is merely a blip in the lifespan of the suppressor. And when the high round counts come and the decibel levels start to rise, I will not have to send my suppressor in for maintenance. No Sir. When the unit hits the 10,500 round mark, I simply need to replace the deflectors within the FHMB. This resets the round count to zero! Keep in mind; this is 10,500 rounds obtained at 20 rounds per minute! Military and LEO withstanding, very few civilians have the finances and time to get this many rounds down range at that rate of fire. If you do, well, good on ya.

I asked Russell what he felt OSS could do better from a manufacture standpoint.

His response was short but to the point: “I would say the […] critique that we have heard multiple times is better communication, explanation and connection with the civilian customer base.”

Another question I asked was about quality control. This question was deliberate as I noticed some gouges on my SRM core brand spanking new, right out of the can. Russell admittedly knew exactly what I was talking about.

He told me: “We have had […] complaints regarding the SRM cores and the appearance of gouges and marks on the exterior tube. These complaints were 100% legitimate and a failure of QC at OSS during the assembly process. We hire a lot of alphas and gunslingers and as a result our guys have a get it done attitude. During a weekend shift, the jig that holds the inner core while the outer tube is pressed and rotated into position broke. In an effort to maintain the delivery schedule, the assembly crew decided to move to the all-purpose problem-solving device known as “the pipe wrench”. It took about two seconds for me to see a returned SRM to know exactly what happened and track it down as anyone who has ever used a pipe wrench knows what marks are left behind. Ultimately this pipe wrench assembly technique did not affect the performance or accuracy of the SRM as the contact areas affected are not essential. It did however create SRM’s that for some reason look like they had been assembled by a pipe wrench… imagine that! About 80 units went out from that assembly shift, most of which have been replaced. We offered to replaced them all at no cost with no shipping charges.”

I really appreciated this response as it is a display of honesty and owning up to a mistake. No blame shifting, no bullshit. They addressed the problem, fixed it and made their customers happy. If you have an OSS SRM core that was “pipe wrench” approved from the factory, contact OSS and they will take care of it.

Only time will tell how successful the OSS Mission technology really is. The After Action Reports (AARs) from the civilian and military users are vital in gauging product performance. Manufactures welcome AARs as they should. AARs help develop better products and ultimately save lives. Currently the OSS Suppressors are seeing action with select units and agencies around the world. Even still, OSS doesn’t claim to be the end-all-be-all of sound suppressors.

They admittedly state, “You will never hear us say that OSS is ‘the best’ or ‘the solution’ for everyone or everything. We will say that as far as weapon suppression is concerned that we offer priorities and capabilities that have never been offered before. We do not build the quietest suppressor in the smallest package; we build the quietest suppressor in the smallest package without adverse effects on the user and weapon system.”

OSS Future Development

OSS continues to innovate and their line-up for 2015 is going to be very impressive to say the least! While I can’t divulge any details yet, let’s just say that the consumer market has only seen about 10% of the different configurations and products that OSS has to offer. What I can tell you is there will be LOTS of OSS variety coming out in the next year or so. This is going to be good! For now, OSS offers other accessories to accommodate their current commercial suppressor offerings. They make a stand off flash suppressor as well as a dedicated muzzle brake known as the Bannar Alpha or Bravo. Needless to say, Russell and the crew at OSS are burning the midnight oil to stay at the forefront of the sound suppressor industry.

The OSS Mission suppressor system can be purchased from authorized dealers. Like all sound suppressors, this is an NFA regulated item and ownership must be blessed by the ATF. In this author’s opinion, it is well worth paying the price of admission to play.

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