Signal To Noise Ratio

So, you are suppressor curious, but do not know where to begin. What are they? What can they do? What don’t they do? What is the proper name? Where does someone even begin? The options can be overwhelming, especially to someone new to the subject. But don’t despair, the problem is not insurmountable. First thing is the proper terminology. Some people will argue that silencer is not the correct term because they do not silence a firearm. However since the man that invented them called it a silencer I am not going to argue. Therefore suppressor, silencer, or the colloquial term of “can” may all be used interchangeably in my opinion

 The answers to most questions can be found with some research. The problem with this approach is a lack of background knowledge. What do I mean by that? A newcomer to the world of suppressors may not know what questions to ask or what the answers mean. What are the right questions? How do I separate the right answer from the incorrect information? Who is a reputable source? All can be problems when trying to learn about a new topic. For example, if I want to buy the best golf clubs but I do not know the rules of the game, the specs of the clubs will not mean a thing.

 So, while you can find answers through an internet search, that may not be helpful. That also doesn’t come with any firsthand experience to give the frame of reference. That is where the idea for this writing comes from. I have seen and participated in an untold number of interactions with customers in gun shops looking to get their first suppressor. That occasioned the thought that I might be able to write some of those answers down.

Legalities

 First thing first, are they legal? Yes, suppressors are legal in most of the country. The National Firearms Act (NFA) governs the transfer of suppressors. To take possession of a suppressor, you must submit the paperwork for the background check and pay $200 transfer tax. This is known as a tax stamp because the ATF affixes an actual stamp to the paperwork once approved, proving that the transferee has paid the transfer tax.

People are often daunted by what feels like a laborious process full of red tape. This is not as bad as it has been made out to be. While the process is more involved than a simple handgun purchase, it still is straightforward. There are just a few more steps than we are accustomed to, but the biggest headache of all is you purchase an item that you cannot take possession of until the paperwork is approved. I have personally experienced wait times as fast as 6 months and as long as 13. While I have seen wait times vary even more than that, at the time of this writing wait times are down to days in many cases.

How Do They Work?

 Will a suppressor truly silence my firearm? Short answer is no. With a few exceptions, we will never make a firearm as quiet as the movies tell us they will be when suppressed. I know it is shocking that Hollywood would give someone the wrong impression about anything but there you have it. There are many components of what we perceive as the gunshot, and we will dive into what the suppressor does and what it does not do.

 What causes the noise of the gunshot? The two biggest causes are the muzzle blast and the sonic crack of the bullet traveling downrange. The sonic crack is the sharp noise created by the bullet breaking the sound barrier. This results from any object travelling faster than the speed of sound. This is the reason that for the quietest shooting possible subsonic ammo should be used.

 What about the muzzle blast? This is the part that a suppressor can help with. Muzzle blast is the result of the rapid uncorking of the barrel. The hot expanding gases from the combustion of the gunpowder create pressure and drives the bullet down the bore. When the bullet exits the muzzle, it uncorks the barrel. This exposes the hot burning gases to oxygen, giving new fuel to the fire. This causes the combustion to suddenly flare. We will sometimes see this phenomenon as a muzzle flash. The sudden combustion makes a loud noise or muzzle blast.

 What a suppressor does is slow this process down. A suppressor captures the gases at the muzzle and allows them to cool before they reach the atmosphere. This reduces the noise from the muzzle blast. Think of this as the difference between popping a balloon versus letting the air out of one. Both balloons have the air let out but at different speeds and subsequently different volumes.

How do I choose which suppressor is right for me? The first question should be, what is the purpose? Suppressors are divided into three primary categories. The three types are determined by what firearms they are to be used on. There are specialty suppressors but for our purposes we will focus om the three primary types of suppressors.

Types of Suppressors

Rimfire

The first are rimfire suppressors. These are small, light cans because of the lighter pressures produced by the 22 rounds. Rimfire cans thread directly to the barrel of the firearm as all 22 firearms are fixed barrels. Most rimfire suppressors are capable of disassembly for cleaning. Rimfire ammunition is very dirty compared to centerfire. This means that rimfire suppressors need regular disassembly and cleaning to remove the enormous amounts of carbon, lead and other residue that accumulate.

Pistol Caliber

The second common type of suppressor is the pistol caliber can. These are either 9mm or 45 caliber. As the description implies these work on pistol calibers. They are significantly larger and more strongly constructed than rimfire cans. However, they can still be disassembled for cleaning. Pistol caliber can still need to be cleaned occasionally to remove the accumulated carbon and residue from firing. The confusing part can be the need for various mounting systems, depending upon the firearm its mounted to.

Any pistol based on the Browning tilting barrel system, which is most centerfire pistols on the market today, will not function properly with the added weight of a suppressor hanging off the front of the barrel. The solution is a booster system, often called a Neilson device. The booster assembly lets the suppressor “float” while the barrel moves reward during firing. This effectively removes the weight from the barrel, allowing the pistol to cycle normally. Once the barrel stops moving the spring forces the suppressor back into its locked configuration, ready for the next shot.

This is exactly the opposite of any firearm with a fixed barrel, such as a pistol caliber carbine (PCC). On a fixed barrel, the can is mounted solidly to avoid misalignment issues that could lead to baffle strikes. When using a pistol can on a fixed barrel firearm, a spacer is used in place of the spring to render the mount solidly. Alternately, some cans allow the user to change the entire mount to replace the booster assembly with a simple fixed mount. This is an important detail for suppressor owners to remember to set the can up correctly for what type of firearm it is to be mounted to.

Rifle Suppressors

The last type to discuss are rifle suppressors. These are sealed units that cannot be disassembled. Due to the extreme heat and pressure inside a rifle suppressor, they do not accumulate the amount of debris that the smaller cans do, and thus do not require cleaning. Rifle suppressors are where people expecting Hollywood quiet will be most disappointed. Rifles are loud and there is no way around that. If you were to think of a rifle suppressor the same way you do ear pro worn when shooting, you would be on the right track. A suppressor on a rifle will reduce the report of the firearm but not negate it.

How to choose the right one

There are many factors that can go into the decision for which rifle can is correct for you and your application. Many people want the “best” can, meaning the quietest. The first caveat on suppressor ratings is that numbers supplied by the manufacturer are not the most useful. Those numbers are merely advertising. Even if the numbers are true and honest, you have no way of knowing how the testing was conducted and cannot therefore compare the numbers against the competition. For direct comparison, we need to know that the testing was done in as close to the same manner as possible. Silencer Shop has numerous videos that show them measuring suppressors. These are helpful because the testing setup is the same for each test and gives a more apples to apples comparison. However, for the most comprehensive, scientific testing the best resource is the Pew Science website. Pew Science goes deep into the scientific minutia, but it is the best comparison tool available.

There are an enormous number of factors that go into the efficacy of a suppressor. Things such as caliber, barrel length, action type and more: are all factors. However, there are a few rules of thumb that can help. The more internal volume of a can, the quieter it will be as the can will have more room for the gases to be held and cooled before they are released. This means that a longer can will work better that the same model in a short configuration. Some cans use larger diameter bodies to obtain greater volume while still limiting length. The tradeoff is that a larger can tends to be heavier and adds more length to the firearm.

One of the most overlooked and misunderstood aspects of buying a suppressor is the mounting system. Rifle suppressors mount in one of two ways, direct thread or quick detach. Direct thread is just as it sounds, the can threads on just like a muzzle device. This works well for precision applications where the can is not removed often. The more common mounting system for semiauto rifles is known as quick detach. This means the can attaches to a muzzle device on the barrel. This allows the mounting and dismounting of the can with little effort.

This is where things can get a little tricky. Every manufacturer approaches the mounting solution differently and some are easier to use than others. This should be a consideration for a suppressor purchase because the muzzle devices are brand specific and not interchangeable. It can also be an added expense if the can is to be used on multiple rifles as the muzzle devices can be $100 or more each.

One solution to this situation is the HUB (Hybrid Universal Base) system. The HUB system allows the end user to change the mount the can will accept. The mount part of the suppressor is threaded to an industry standard pitch and can be exchanged with any number of options. If the owner already has a preferred mounting system on a rifle the suppressor can be adapted, instead of replacing muzzle devices. There will still be some additional expenses but that buys much more flexibility and utility from one suppressor.

So, in closing, there are a number of factors that must be weighed if someone wants to buy a suppressor. First is, what type of suppressor? What features do I want? What firearm is it going on? The adage there is no free lunch is true. A suppressor purchase, like all of life’s choices, is a balancing act of many factors. Cost, length, weight, mounting system, etc. are all things to consider. And the right choice for you depends on what you want to do with the suppressor. You need to decide what factors are most important to you and weigh your options accordingly. The main warning that I would leave with anyone looking to get into the suppressor world, is that much like tattoos or potato chips, it’s hard to stop at one. Once you experience the fun of shooting suppressed you will want more. You have been warned.

Chris Norville