By David Lewis
You can read part 2 here.
This project is a comprehensive look at silencers with testing data that shows exactly what difference a suppressed firearm can make on sound levels while shooting.
Understanding How Firearm Silencers/Suppressors Work
When you fire ammunition from a gun, the ammo generates hot pressurized gases that need a place to escape.
As these turbulent gases exit the firearm, the dramatic change in pressure causes a loud blasting sound. A silencer’s job is to redirect these heated gases through a system of chambers and baffles to slow down, cool, and limit the pressure and noise emitted from a firearm’s barrel.
One great example of how silencers work can be seen when looking at car’s muffler. A muffler’s job is to take the hot gases and noise generated from an internal combustion engine and slow them down through a system of tubes and baffles. The result comes out as exiting exhaust within an acceptable audio range.
Just like car mufflers, there is no one-size-fits-all solution for firearm silencers. They come in different shapes and sizes. This lets us control how loud or quiet we would like our firearm to sound.
Firearm silencers are so similar to car mufflers because the inventor, Hiram Percy Maxim, actually helped with a lot of the research for improving automobile and industrial silencers. His company, Maxim Silencers, is still running strong over 100 years later and remains a leader in the industrial noise control business.
Suppressor vs. Silencer
Silencers are continually a hot topic of debate between gun owners and gun control advocates. The debate usually starts when asking what exactly we should call these devices.
The term “silencer” is really a colloquial term for firearm suppressors, and one of the most misleading aspects of the whole debate. Contrary to the term, “silencers” do not completely silence a firearm.
Similar to the whole magazine vs. clip argument, there are staunch advocates in favor of never using the term “silencer” when discussing firearm suppressing devices. Many point to the way silencers are portrayed in the media as the basis of inaccurate representation of their capabilities.
When used in action films, the bad guys are usually running around gunning down their targets, all while remaining undetected due to the whisper like sound levels of their evil guns. While this makes for a great story-telling device, the real-world accuracy of how a silencer actually performs is much different than its Hollywood portrayal.
In reality, most civilian-accessible firearms emit sounds ranging from 140-175 decibels. Silencers only marginally suppress a gun blast, bringing those levels down to around 120-150dB. Most of the time, the sound is still very obviously identifiable as a gun shot.
Many gun owners also fear that inaccurate portrayals could lead to even more regulations for silencers/suppressing devices.
For what it’s worth, the ATF uses the term “silencer” in their yearly statistical update for sales and applications for firearms and other NFA items.
Oh, and Mr. Maxim, the inventor himself, called them silencers. So, in the suppressor vs. silencer debate we’re going to call them silencers out of respect to Mr. Maxim. But, know that we’re not advocating the Hollywood portrayal of these tools as accurate.
How Effective are Silencers?
When it comes to a silencer’s capabilities, there is a short and simple answer to the question, “How much quieter is a gun with a silencer?” The answer is, it depends.
There are many factors that go into how a suppressed gunshot will sound. They include the type of silencer used, firearm/caliber choice, and ammunition being fired. Even ambient temperature and atmospheric conditions can all impact the overall sound a firearm emits.
Silencers mainly focus on controlling the sound level emitted from firing a round of ammunition. But keep in mind, a firearm’s action also creates mechanical sounds when cycling rounds of ammunition. These sounds are in no way changed or reduced by the use of a silencer.
Caliber and Firearm Choice
Since silencers can be expensive and a hassle to purchase, many people opt for a model that will work well with multiple calibers. One popular choice is using a .30 caliber silencer used to shoot rounds such as .308/7.62 NATO, and 300 AAC BLK, but also using it to shoot smaller .223 and 5.56 NATO rounds.
Even though a .30 caliber silencer will suppress a gunshot from a smaller caliber, the sound isn’t as suppressed as it would if the shooter were using a model made specifically for the round being fired.
Barrel length can also have an effect on the overall sound levels of a gunshot.
Generally, the shorter the firearm barrel, the louder the blast will be. A longer barrel allows more time for the powders and gases to burn before escaping the end of the muzzle.
Subsonic vs Supersonic Ammo
Along with the sound of the action, there is an additional insuppressible noise that comes into play, but it has to do with the actual projectile itself.
Since the use of a silencer doesn’t alter the performance or velocity of the bullet being fired, when the projectile breaks the sound barrier you will hear what’s commonly known as a sonic boom or in this case, a sonic crack.
This audible confirmation of a high velocity projectile breaking the sound barrier can reach upwards of 150dB, a level that’s capable of rupturing eardrums.
Atmospheric conditions like humidity and temperature however do have an effect on the speed at which the sound barrier is broken. That speed usually falls in the range of 1,100 feet per second. Although, the warmer it gets, a greater velocity is needed to break the barrier.
For instance, the following chart identifies temperatures and the corresponding velocity at which the speed of sound is broken:
Most rifle ammunition is manufactured to produce supersonic speeds, although there are some exceptions. Pistol calibers on the other hand are usually a better choice to achieve speeds less than 1,100 feet per second, also known as “subsonic.”
It’s possible to shoot both subsonic and supersonic rounds through suppressed firearms. Just keep in mind that the sonic crack can in no way be altered or suppressed itself.
Benefits of Suppressing Firearms
Preserving Hearing Health
Even if you’re not an avid shooter or gun owner, it’s easy to understand one simple fact; exploding gunpowder is really loud. It also doesn’t take an audiologist to understand that constant exposure to loud noises can lead to hearing loss.
Hearing loss and tinnitus caused by overexposure to loud noises are two of the most common medical conditions for recreational shooters and hunters. In fact, WebMD claims hearing loss is the third most common health problem in the United States.
The use of a silencer can reduce the deafening sound of gunfire for hunters and shooters by 30-40dB. This is comparable to benefits of using in- or over-the-ear hearing protection.
So why not just wear ear protection all the time? While we definitely recommend using hearing protection, every shooting situation is different and ear-pro may not always be an option.
For example, in a law enforcement shooting situation, an officer may not have time, nor the desire to worry about protecting their hearing. Safety and survival of the officer and innocent bystanders is the key concern.
Shooting in enclosed spaces, as in a potential home defense situation, can also lead to permanent hearing damage. The reverberations of a gunshot off of the surrounding walls and ceiling can amplify the blast, regardless of the firearm used.
“…the only potentially effective noise control method to reduce students’ or instructors’ noise exposure from gunfire is through the use of noise suppressors that can be attached to the end of the gun barrel.” – The Centers for Disease Control and Prevention (CDC)
Hunters typically don’t wear ear protection when out in the field, either. For starters, a hunter needs to be able to clearly listen for the game they’re after. They also need to have full situational awareness, with the ability to clearly communicate with other hunting companions. And in the case for using electronic hearing protection when hunting, most state laws forbid the use of electronic devices that aid in the locating of game animals.
Research that demonstrates the superiority of silencers over traditional ear protection has been published by Matthew P. Branch, MD. He found . . .
“All suppressors offered significantly greater noise reduction than ear-level protection, usually greater than 50% better. Noise reduction of all ear-level protectors is unable to reduce the impulse pressure below 140 dB for certain common firearms, an international standard for prevention of sensorineural hearing loss . . . Modern muzzle-level suppression is vastly superior to ear-level protection and the only available form of suppression capable of making certain sporting arms safe for hearing.”
Recoil Reduction and Accuracy
It’s natural to flinch in anticipation of loud sounds or movements. It’s in our genes. This is commonly experienced by many people when shooting a firearm.
If you’ve ever spent time at the range or in the field hunting, you probably noticed how your shoulder was somewhat tender the next day due to the recoil of the firearm. Anticipating this harsh recoil, shooters tend to brace for the impact and the blast of the muzzle just prior to pulling the trigger.
These additional small movements by the shooter can result in poor accuracy down range.
By redirecting and cooling the fired gases, silencers are beneficial in mitigating the overall recoil felt by the shooter. In return, the shooter can overcome the instinct to flinch and achieve better shot placement at the range and more humane kills when hunting.
Muzzle Flash Reduction
By using a silencer or suppressor, you can also greatly reduce, or in many cases eliminate the bright muzzle flash caused by the burning gases exiting the barrel.
The bright flash emitted from a gun blast can cause temporary blindness and disorientation of the shooter or others in close vicinity. This is typically only an issue when shooting in low light or night time settings, like during a home defense situation, or a night-time predator hunt.
People generally don’t like to be interrupted by unwanted noises. The same principle applies to shooting on personal property or rural gun ranges. Even on large tracts of land, noise ordinances can still come into play and neighboring properties may not want to hear you plinking away all afternoon.
Silencers can help soften these noises from personal and public ranges, as well as hunting properties. And a happy neighbor is well worth the investment, trust me.
In part two tomorrow, we’ll discuss the legality of suppressors, their popularity, and data showing just how effective they are in reducing damaging noise levels on different kinds of firearms. Stay tuned.
This article originally appeared at ammotogo.com and is reprinted here with permission.