Having a class 3 licsense, ahem, sucks. It like having an ATF agent move in an live with you.
The first firearm suppressor was invented in 1910 by Hiram Maxim. Maxim was also the man responsible for the first true machine gun. While a suppressor may greatly reduce the noise of the shot, the term "silencer" is technically incorrect because there is no way to effectively silence any firearm. The noise of the shot may be dampened or suppressed but there are no silent firearms in existence.
Sound Components of a Shot and how a Suppressor Works:
There are four distinct components that together make up the noise we perceive as a gunshot. In order of loudness, these are:
- Pressure Wave from rapidly expanding propellant gases
Sonic Crack of bullet
Mechanical Action Noise
The pressure wave, produced by the rapidly expanding propellant gases is the only noise component that a suppressor can reduce. The suppressor reduces noise by two mechanisms. The first is it slows the release, through expansion and turbulence, of high-pressure propellant gases that we perceive as a "bang". The second is due to Newton's Law of Thermodynamics (Energy can neither be created or destroyed. It can only be converted from one form to another), where some of the kinetic energy of the noise impulse is converted to heat.
The only way to remove the sonic crack of a high velocity bullet is to utilize subsonic ammunition. Some cartridges are inherently subsonic, while most others can be downloaded to a velocity below the speed of sound. Some integral suppressors utilize ported barrels to bleed off propellant gas and thus reduce the velocity of the bullet.
Bullet flight noise is not loud enough to be sensed by the shooter. However, even subsonic bullets can be heard if they pass close by a person. This noise resembles a whooshing or swishing sound as the bullet flies through the air. Flight noise is too quiet to be heard above a sonic crack.
The most common method of measuring sounds is the Decibel system. Decibels are a logarithmic scale; meaning the values are non-linear. Eg. A change from 100 to 200 dB does not represent a doubling of the noise level. It represents an increase of 1000 times.
Most suppressors for supersonic cartridges can realistically be expected to reduce the noise of firing by 18-32 dB depending on the design. This represents the limit imposed by the noise of the supersonic projectile. As the suppressor reduces the noise of the shot, the sonic crack becomes the dominant sound. In subjective hearing tests, a suppressed, supersonic cartridge will sound approximately as loud as an unsuppressed .22 rimfire rifle or about 139-141 dB. Suppressors for subsonic cartridges may approach 40 dB of sound reduction however; this is the practical limit of sound reduction at this time. Subsonic systems can be as quiet as 115 dB, which is less than the action noise of a Sterling Submachine Gun (open bolt, blow back action). The dominant sound is the bullet striking the target.
Like firearms, different suppressor designs work best in different applications. Size and weight always work against noise reduction. As a result, one must find a balance between the size and weight of a suppressor and the degree of noise reduction desired for the mission. Suppressor designers are constantly trying to strike a balance between size and weight and noise reduction, which is why there are so many different designs available.
Suppressors make very effective muzzle brakes. A suppressor reduces the recoil of any firearm by about 30% or as much as a muzzle brake. Unlike a conventional muzzle brake, the suppressor will not blow noise back towards the shooter or cause dust and debris to be blown up, giving away the shooter's location.
Suppressors on tactical weapons allow more accurate and faster target engagement due to reduced muzzle jump and reduced flash in low light conditions.
Suppressors on very large caliber rifles (.338 Lapua or .50 BMG) greatly reduce recoil, muzzle flash, noise and blast. They increases the shooter's comfort level considerably over a conventional muzzle brake because the suppressor directs propellant gases forwards, away from the operator, in a very small arc.
The removal of painful muzzle blast can increase marksmanship as a result of a reduction in flinching, as well as increase the speed of follow up shots.
Reduced muzzle blast can allow longer training sessions and more shooting practice. The muzzle blast from large caliber weapons can be so intense that ear defenders and earplugs may not be effective. In this case the suppressor is the best method of protecting the operator's health.
Suppressors practically eliminate muzzle flash so they are appropriate for use in dark conditions or where the atmosphere may contain explosive gases. A bit of tape over the muzzle of the suppressor will stop gases from entering the suppressor.
Once the first shot has been fired, the suppressor is full of burnt propellant gases, thus providing a non-explosive atmosphere inside the tube.
Types of Suppressors:
Suppressors can be divided into two main categories: Integral and Muzzle. Integral suppressors are designed as a permanent part of the firearm. Muzzle cans are designed to be fixed and removed easily and they do not affect the functioning of the firearm. Neither type of suppressor has an advantage in sound reduction. Integral systems are used where barrel porting is required to reduce the velocity of supersonic ammunition. Integral systems do not suffer point of impact changes as a result of the fitting or removal of the suppressor. They also tend to be more compact.
There are many different ways to mount a suppressor. Two-point mounts are the sturdiest and the least likely to result in a misalignment. Mostly it is only integral suppressors that use two point mounts.
Employment and Techniques of Suppressed Firearms:
It is desirable to suppress a gunshot for many reasons. For entry teams, suppressed weapons allow increased command and control, as operators do not have to wear hearing protection. Suppressed weapons allow operators to distinguish between shots fired by one of the team or a perpetrator.
Suppressed shots are also more difficult to pinpoint, giving the operator an advantage over the perpetrator in the confusion of an armed encounter for greater survivability.
Military snipers can expect to be subjected to intense mortar or artillery fire should their location be inadvertently revealed. The suppressor could be the most important piece of "camouflage" used by a sniper team. The suppressor camouflages the rifle shot by almost eliminating muzzle flash and blast that can give away a sniper's location. Proper positioning of the shooter to cause the bullet to pass close by one or more hard objects can add to the enemy's confusion as the muffled shot will be veiled by the sonic crack which will seem to come from multiple locations as a result of it bouncing off hard objects.
Police snipers can also benefit from the use of suppressors to dampen the noise of the shot for public relations. Even experienced shooters view a quiet gunshot as being from a "less powerful" or "less dangerous" firearm. A full power sniper rifle fired in an urban location can attract unwanted public relations problems.
Suppressors and Accuracy:
A properly designed and mounted suppressor should have no negative effect on the accuracy of the firearm. In fact there is some indication that suppressors actually increase accuracy by stripping the high velocity propellant gases from around the bullet. Without the suppressor, the gases push past the bullet, causing it to yaw slightly as it leaves the muzzle. A muzzle-mounted suppressor will change the point of impact of any firearm it is attached to. However with testing this effect can be corrected for by adjusting the sights.
Potential Problems and Hazards Associated with the Use of Suppressors:
One of the biggest hazards comes from improperly mounted suppressors or a suppressor that loosens during use. This can cause the suppressor to lose alignment with the bore, possibly resulting in baffle contact which can tear the suppressor off the firearm or blow it to bits in a catastrophic failure. During use, all suppressors should be checked for proper tightness regularly.
Not all suppressors are designed to survive full-auto fire or even a high volume of semi-auto fire. A high volume of fire through a suppressor not designed for it can cause the suppressor to fail from baffle collapse or extensive baffle damage. It can also destroy the rifle's barrel from excessive heat buildup in as few as 200 rounds.
Minor suppressor hazards include burns from a hot tube as well as propellant gases and unburnt powder blowing out the ejection port of semi-automatic firearms. Operators should take care to wear proper eye protection when using suppressed weapons.