There are four noises which make up the "boom" one hears when shooting a firearm. The first is the action noise (i.e.: the hammer hitting the firing pin, the slide/bolt cycling, gas escaping though the ejection port). The second is the bullet flight noise. If the round travels faster than the speed of sound, which is approximately 1050fps, there will be an audible “crack” heard by the shooter and those the projectile passes. The third is the bullet striking the target. The last noise associated with the firing of a firearm is the combustion noise hitting the atmosphere when the projectile leaves the barrel. The gasses that pushed the projectile from the barrel are going faster than the speed of sound and typically still burning. The “boom” of the gasses hitting the atmosphere is typically louder than the other noises, which is why the boom generally is all the shooter and those near the shooter hear.
Firearm silencers work in the same manner as mufflers for cars and lawn mowers. Both provide a controlled environment in which the gasses can expand and cool before exiting into the air with less energy and noise. A typical silencer has a casing segregated into chambers by partitions called baffles. Each baffle has a passage through which a projectile can pass. When the host weapon is fired, the projectile exits the barrel and passes through the length of the silencer, but the gases that propel the projectile expand into the baffled chambers where they are temporarily trapped. When they do find their way out of the silencer, the gases have slowed considerably and thus produce less sound.
What are sound suppressors used for?
Silencers are “hearing protection” that attaches to your firearm, not unlike a muffler on an automobile.
OSHA limits impulsive or impact noise at 140dB peak sound pressure [29 CFR 1910.95(b)(1) or 29 CFR 1926.52(e)]. “Hearing Safe” in the Firearms Industry refers to a gunshot that produces less than 140dB peak pressure. By way of comparison, a 1911 45ACP pistol or a 16” 5.56mm rifle produce approximately 165dB peak sound pressure. Decibels are logarithmic, meaning that sound pressure doubles or halves approximately every three decibels you increase or decrease the sound.
For recreational shooting, it’s acceptable to wear hearing protection which will block out a portion of the noise produced from shooting firearms. However, this is not really an option for Military, Law Enforcement or Citizens using firearms for home/property defense. As a result, with every shot these individuals are producing noise that can not only permanently damage their own hearing, but those of individuals around them.
Imagine if in 1934, the government thought that people buying automobiles might run people over in crosswalks because pedestrians wouldn’t hear the approaching vehicle and imposed a $200 tax to possess a muffler. What would it sound like when you walked out your front door?
Although silencers cannot muffle every noise that is associated with the discharge of a firearm, they can greatly reduce some aspects of the process. Silencers primarily reduce the noises associated with “muzzle blast,” by providing the escaping gases baffled chambers in which to expand and depressurize prior to escaping the silencer.
Who would want to use a sound suppressor and why?
A silenced firearm is eminently more enjoyable to shoot than one without a silencer. Silencers generally increase the accuracy of a host firearm while reducing recoil and eliminating up to 90% of the muzzle signature. Shooters are able to concentrate more on breath control and trigger pull when they are not subjected to the fatigue and distraction of a deafening and bright muzzle report. Beginning shooters are typically not intimidated when introduced to the shooting sports with a silenced firearm. They are able to easily hear instructions given to them by trainers because the report of a host firearm is reduced to below the OSHA guideline level for hearing damage. Silenced firearms are also less likely to disturb people, livestock, or wildlife that may be in close proximity to where you shoot.
What are key pieces to know about suppressor ownership and usage?
Silencers are legal for civilian ownership in 42 states (and counting). Contrary to popular belief, silencers are and always have been legal to own under federal law. Getting one takes just two simple forms. It's as easy as locating a dealer in your state that sells silencers, filling out and mailing the appropriate forms to the BATFE, waiting patiently, and then picking up your new can and start enjoying the countless benefits of quieter shooting. The paperwork associated with ownership never needs to be renewed. It is a onetime lifetime registration per silencer.
Are there different types of suppressors for pistols and rifles? What different kinds of suppressors are there?
The baffles in a 5.56mm silencer have one of the hardest jobs on earth. Not only do they have to contend with a blow-torch assault from the super heated muzzle gases, but they are also bombarded with particles of unconsumed propellant traveling faster than the speed of sound. We have addressed this issue by using a high temperate alloy known as Inconel in several of our rifle silencer designs. The pressures caused by pistol rounds are not as harsh on your silencer and manufacturers have the ability to use lighter weight materials that are just as effective at reducing the overall sound signature. Our pistol silencers are just as well built as rifle silencers, but they do not require a fully-welded core and you have the option to take them apart for cleaning.
What is a Wet/Dry suppressor?
Most modern silencers are designed to be fired in a dry condition. This means that they require no performance enhancers, such as water, grease, or oil, in order to achieve a reasonable level of sound reduction. However, most centerfire pistol designs will exhibit less muzzle and ejection port flash, and a reduction in overall sound signature if the interior of the silencer is treated with a small amount of ablative media, like plain water. The sacrificial media typically remains effective for 1-2 magazines of use before it must be replenished. Centerfire rifle silencers can be shot with an artificial environment if there is the hazard of a potentially explosive atmosphere. Otherwise, the employment of an artificial environment in rifle silencers is discouraged.
As with most products, technology has improved since 1909. By way of example, prior to the Advanced Armament Ti-RANT 45, there really was not a .45 ACP handgun silencer that would reduce the sound of a shot under 140dB without using an ablative material. All .45 ACP silencers required a coolant to get to "hearing safe". Even with today's "cutting edge" technology, shooting "wet" will reduce the report even further. While not required with the Ti-RANT series of handgun silencers, it is still a popular option.
Shooting a handgun silencer "wet" is as simple as introducing about 5cc's of simple water, or other ablative materials such as wire pulling gel, ultrasonic gel or other coolants into the rear of the silencer.
What are the basic parts of a suppressor and what does each part do?
All silencers feature an expansion or blast chamber that the bullet must travel through before making its way through each subsequent baffle and eventually exiting the silencer. The expansion chamber is generally the chamber with the largest volume within the silencer to allow for the initial introduction of the hot expanding gases propelling the bullet. These hot expanding gases eventually make their way through the baffle stack consisting of a designated number of baffles and spacers, which are essentially smaller chambers designed to disrupt the natural path the gas would take. By the time the gases exit the silencer, they have slowed considerably and produce a quieter sound signature.
Why do I see so many different kinds of mounting options? Are they maker/caliber specific?
Most manufacturers have designed their own mounting system for use with their silencers. AAC’s revolutionary 51-tooth ratchet system is one of the most intuitive silencer mounting systems available. The end user can securely install the silencer on the weapon in under three seconds, one handed, without the use of tools and with no moving parts. The design incorporates a secondary retention ratchet latch that prevents the silencer from loosening during fire. Our mounts are also compatible across different calibers, as long as the end user purchases the correct thread pitch for the weapon system. This allows the end user to utilize their silencer on a smaller caliber, such as using a 7.62 silencer on a 5.56 weapon system.
Using a 7.62mm oriented silencer on a 5.56mm host firearm is a very popular option for consumers. Comparing the 762-SDN-6 to the M4-2000 (a premium 5.56mm silencer), the 762-SDN-6 is about an inch longer, two ounces heavier and about two dB louder than the 5.56mm dedicated M4-2000 when used on an M4 platform host weapon.
Screw-on versus QD mounting, is there a difference?
Used by most rimfire and centerfire pistol silencers, as well as by many centerfire rifle silencers, direct thread mount refers to silencers that attach to the end of the barrel via screw threads on the muzzle itself. Direct thread silencers can be used on multiple hosts. Fast attach silencers rely on an attachment method that is faster and easier to manipulate with gross motor skills than a direct thread silencer. Rather than attaching directly to the barrel of the host firearm, fast attach silencers couple to an adaptor that is semi-permanently installed on the host weapon barrel. The most common adapter designs are flash hiders, muzzle brakes, compensators, and three lug barrels/adapters.
How do flash hiders affect a suppressor? How about muzzle brakes?
Both our flash hiders and muzzle brakes provide a solid mounting point for our silencers to attach to. Flash hiders have no negative effect on the silencer, but muzzle brakes can actually extend the serviceable life of your can. The blast chambers on our muzzle brakes act as a sacrificial blast baffle and can take the brunt of the weapon’s muzzle blast. There is no sound difference between flash hiders, muzzle brakes or flash suppressing muzzle brakes with the silencer mounted. However, muzzle brakes do tend to produce more noise to the shooter than flash hiders without a silencer attached.
How does caliber affect suppressor choice?
Certain calibers are much easier to effectively suppress than others. Any bullet traveling fast enough to break the sound barrier will cause a sonic crack and will not be “Hollywood quiet.” The speed of sound is roughly about 1050 feet per second at sea level. While the silencer will still slow and cool the gases prior to releasing them into the atmosphere and the overall sound signature of the combustion gases will still be reduced, the sonic crack of the round traveling through the air will produce a sound in the high 130dB range. Some of the most commonly available rounds that are just as quiet as the movies are .22LR, 9mm (147gr. subsonic), and the new 300 AAC Blackout (220gr. subsonic). If you are seeking the greatest overall sound reduction, stick with one of the above mentioned calibers and try not to walk away smiling.
Can I run a larger caliber suppressor on a smaller caliber gun? What are the positives and negatives to a set up like that?
As a general rule of thumb, you can use a larger caliber silencer on a smaller caliber firearm, provided you follow some simple guidelines. There are three categories of silencers: rimfire, centerfire handgun, and centerfire rifle. As a general rule, stay within the same category when using your silencer on an alternative caliber. You can use a silencer on an alternate caliber as long as the projectile diameter and pressure are equal to or less than the caliber the silencer was designed for. You can use 5.56mm in a silencer designed for 7.62mm, but you should not use a .300 Ultra Mag round in a 7.62mm silencer. Stay with equal or less case capacity then the silencer was designed for. Using a silencer in an alternate caliber can be fun and cost effective, if you use common sense and stay within these guidelines.
I sometimes see different length suppressors for the same application. Does length affect sound suppressor effectiveness?
Length and volume affect sound, but there is a point of diminishing returns. At AAC, we are constantly striving to achieve the same level of sound level reduction in shorter silencers. Through constant research and development, superior material selection, and improved baffle design, we hope to achieve our goals of continuing to offer the best silencers on the market.
How does the heat generated from firing a gun affect the suppressor?
The hot expanding gases that propel the projectile are trapped within the silencer and cause the temperature of the silencer to increase. The more intense your firing schedule, the hotter the silencer (and the barrel) will become. Higher pressure rounds also lead to higher temperatures within the silencer because of the amount of hot expanding gases that the silencer will trap.
What kind of lifespan can I expect from your suppressors?
Our user-serviceable silencers, which include all of our current rimfire silencers and the Ti-RANT series of pistol silencers, have the ability to be taken apart and serviced by the end user. A take-apart silencer that is maintained in accordance with the owner’s manual will last a lifetime. Our rifle silencers feature fully welded cores and are constructed using advanced metals to aid in the durability. We have tested silencers in excess of 30,000 rounds that have had no noticeable degradation in overall sound quality. With all silencers, lifespan is determined by several factors, including caliber, barrel length, muzzle device, and firing schedule, so there is no definitive answer regarding lifespan. Your silencer will typically outlast several barrels on your host firearms.
Can your suppressors be maintained for longevity? If so, how do I do it?
Due to the inherently dirty nature of rimfire ammunition, silencers trap much of the unburned powder, lead, and filler that would otherwise be expelled out of the barrel and into the atmosphere. As such, rimfire silencers should be cleaned on a regular basis.
Centerfire pistol silencers have traditionally been sealed. However, through constant research and development we have determined that there is an added benefit for users being able to fully disassemble their pistol silencers for deeper cleaning.
Centerfire rifle silencers typically utilize fully welded or sealed designs, and are traditionally cleaned by a solvent bath. Silencers with fast attach mechanisms should have the receptacle area that houses the host weapon adapter, as well as the adapter, cleaned of carbon fouling and copper build up.
All silencers should be maintained according to their manufacturers suggest cleaning regimen.
What kind of cycling issues might I have with using a suppressor?
Rimfire silencers and locking breach systems, like bolt or break open rifles are typically issue free when using a silencer.
Handguns with "Browning tilting barrel" type systems need a Neilson type device, like the Advanced Armament ASAP (Assured Semi Automatic Performance) system for 100% reliability.
Many modern piston type rifle designs incorporate a "Silencer" setting due to increased back pressure. Some consumers prefer an adjustable gas system (like the Noveske Rifleworks "Switch Block") to tune their rifle for less back pressure and softer function, but it's not a function issue, more a shooter comfort issue.
There can be ammunition cycling issues with specialty ammunition, like some "subsonic rifle ammunition" that is not designed to cycle. Specialty subsonic cycling rounds in 5.56mm tend to be very expensive and reliability can be spotty. These issues were of primary importance in the design of the 300 AAC Blackout round. The Remington 220gr Subsonic Sierra OTM round was designed to provide reliable semi or full auto performance, while costing a fraction of the price that you pay for less reliable specialty “cycling subsonic”.
Does ammunition choice affect sound output? What are subsonic rounds?
"Subsonic" means that when the projectile leaves the barrel of the firearm, it is traveling under the speed of sound, which is approximately 1050fps.
Rounds traveling over 1050fps will break the sound barrier, creating a sonic crack that typically will be louder than the suppressed gunshot.
In rimfire, the cataloged velocities are based on a rifle length barrel. The longer the barrel, typically, the more effect the propellant gases have on the round. That means that most "standard velocity" or "target" ammunition will remain under the speed of sound out of a handgun. However, in rimfire rifles, a round that would have remained under the speed of sound in a handgun may make the round cross over the 1050fps threshold, creating a sonic crack. The noise associated with supersonic velocity ammunition, especially in rimfire hosts, can be louder than the suppressed shot. Typically, rimfire rifles will require ammunition labeled as "subsonic" for the projectile to actually remain subsonic.
Heavier loaded handgun cartridges will typically remain subsonic when fired from a handgun. Some examples are, 147gr 9mm, 180gr .40 S&W, and 230gr .45 ACP loadings that will typically remain subsonic in a handgun. Consumers using handgun caliber rifles may find they may need a heavier projectile, like a 158gr 9mm round when used with the longer barreled hosts.
The vast majority of centerfire rifle rounds are designed to travel well over 1050fps. As mentioned earlier, there are specialty subsonic type loadings in 5.56mm and a few other centerfire rifle calibers. These loads can, at best, be expensive and less than reliable. 300 AAC Blackout, which is a SAAMI approved round, is the exception to the rule. It was specifically designed with both subsonic and supersonic use in mind.
Another issue with subsonic/heavier projectile use can be barrel twist. The vast majority of consumer grade firearms are designed by companies to stabilize projectiles within certain "common" bullet weights and going outside that design parameter can cause stability issues for projectiles. “Stability issues” cause end cap strikes and decrease accuracy (with or without a silencer). Two glaring examples can be Aguila 60gr "SSS" ammunition used in rimfire handguns. This round was designed for increased backpressure, to increase reliability with 22LR conversions. It rarely stabilizes in standard rimfire barrels.
Stabilization is another common issue with subsonic 7.62mm projectiles, which typically run in the 220gr range. These length projectiles need faster twist rates, like 1/10” or faster to stabilize. A consumer wanting to use subsonic ammunition with their host firearm should check with the ammunition manufacturer if they are unsure of their host/twist/ammunition combination.
Is using a suppressor harsh on the gun's system?
This depends on the operating system of the firearm, but typically a silencer is not harsh on the gun's system. Increased back pressure and the re-routing of gasses will typically cause the firearm to get dirtier faster. This remains true for any firearm system. Can the use of a silencer accelerate wear and parts breakage over a firearm without a silencer? Yes, but it should be noted that not shooting with a silencer can also cause accelerated wear and parts breakage on the shooter.
What are boosters and Nielsen Devices?
Firearms utilizing the Browning tilting barrel design, during the cycle of operation, require that the barrel tilt upwards at the muzzle. The shorter the barrel, the more exaggerated the angle of the tilt. Putting weight on the muzzle end of the pistol is like adding weight to the end of a seesaw. The chamber end of the barrel locks into the slide and the weight of the silencer cams pressure upwards. When the pistol is fired with weight at the muzzle end, these types of handguns (including 1911s, Glocks, Sigs, M&Ps, and most popular brands/designs on the market) have trouble unlocking. If they do manage to successfully unlock, they will have trouble lifting the weight of the silencer and cycling properly.
A Nielson type device, like the Advanced Armament A.S.A.P. (Assured Semi-Auto Performance) system, assists the pistol and allows for reliable function. The A.S.A.P. system consists of an action spring and a piston that is threaded to mate up with the host weapon's muzzle threads.
As the projectile enters into the silencer, the expanding gasses behind it impact the baffles. As the baffles slow, redirect, and cool the gases, the pressure behind them force the silencer forward, like the wind hitting an umbrella you are carrying. This momentarily relieves the weight on the end of the barrel, giving the barrel enough time to unlock and cycle reliability, before the action spring snaps the silencer back into place, ready for the next shot.
The ASAP System also allows for the shooter to change the point of impact of the projectile in ten increments without the use of tools. To utilize this feature, the user should attach their silencer to the host weapon, pull the two in opposite directions, and rotate the silencer into one of the designated alignment slots.
How much sound can I expect to reduce from my gun?
There is a bit of a technical description of Decibels in the answer for question #2.
To recap, three decibels will basically double or half the amount of sound. By way of example there, a 16" 5.56mm AR15 type rifle is approximately 165dB, a 10" 5.56mm AR type rifle is approximately 168db, or roughly twice as loud as the 16" rifle, all factors otherwise being equal.
We went over that there are four sounds that occur, with the combustion noises being the loudest of the noises.
Our catalog lists the amount of sound reduction, as well as the host/silencer/ammunition combination used to get that result.
You will note that the vast majority of the silencers in the 2012 catalog will get the sound of the gunshot below the 140dB, "Hearing Safe" level.
By way of example, the M4-2000, when used on a 14.5" M4, will reduce the sound of the shot 32-34dB, which will take the hearing damaging sound down to the mid-130dB range. Even applied to the 10” barrel you get the rifle below 140dB when using the M4-2000.
The simpler answer is that with the use a quality made silencer, you will be able to shoot your firearm without doing permanent hearing damage to you, your friends, your children, or in the case of first responders, your co-workers or the victims you are saving.
What are the pros to using a sound suppressor?
• Silencers protect the shooter and those nearby from temporary hearing threshold shift and from irreversible hearing loss, which can result from single shot exposure.
• Silencers help users maintain command and control by enabling team members to communicate during live fire.
• When used on rifles, silencers generally improve accuracy by promoting the harmonic stabilization of the barrel and reducing gas-induced instability as the bullet exits the muzzle.
• Silencers prevent "blooming" of night vision equipment and help preserve unaided night vision by eliminating muzzle flash.
• Silencers reduce recoil and muzzle flip allowing for more accurate and faster follow-up shots.
• Silencers disguise the location of the shooter by reducing muzzle flash and minimizing environmental disturbances.
• Silencers improve training scores by minimizing recoil and muzzle blast and allowing the instructor's commands to be clearly heard.
• When every member of the team goes in utilizing a silencer, the opposition is instantly identifiable by their muzzle flash and noise.
What are the cons to using a sound suppressor?
Silencers inevitably add length and weight to the host weapon system, which is less than ideal. Through Advanced Armament's constant research and development, superior material selection, and improved baffle designs, silencers are able to be made smaller and lighter, but just as effective as the products of the past.