Posted On September 12, 2014 by Print This Post

Silencers, don’t. By Adam Firestone

All I know about silencers I learned from action movies, primarily those featuring Agent 007. That’s all I knew before I met ADAM FIRESTONE, that is. Most of what I “knew” about silencers was wrong, as it turns out. (Adam is like a Snopes for firearms!)

And really, who doesn’t love James Bond movies?

Quicksilver_.22_silencer_4

The problem is that movies, if anything, exacerbate the already egregious firearms errors found in Ian Fleming’s books. (Fleming wrote brilliant thrillers; weapons just weren’t his area of expertise.) But, back to the movies…

 

How many times has a character, Bond or otherwise, used a silenced handgun? Probably too many to count. Silencer use is typified by this clip from Goldeneye, http://www.youtube.com/watch?v=zdK2HP434iI  (click on the image to view):

 

Of specific interest is the sequence from 0:30 to 0:33. Let’s forget for a moment that Sean Bean’s character, Alex Trevelyan, is using a Browning BDM, which, anachronistically, wouldn’t be produced for another five years after the fictional scene’s 1986 date, and instead concentrate on that tube at the pistol’s muzzle end.

 

For years, audiences have been conditioned to recognize that “tube at end of pistol = silencer” and “silencer = really quiet shot.”

 

I suppose that in batting averages, a .500 isn’t bad. But with respect to technical accuracy it’s unacceptable.

 

(Read that “Epic Fail!”)

 

In other words, a tube-like extension at the end of a pistol is probably a sound suppressor of some sort (“Silencer” is actually a trademarked term that grew beyond its initial usage, much like “ketchup” has displaced the use of “catsup.”), but suppressors do NOT change the sharp crack of a pistol shot into a muffled “Puh-TEW.” A suppressed gunshot sounds a lot like….a gunshot.

SILENCER-07-04

The suppressor has an interesting history.  An American inventor, Hiram Percy Maxim (who, incidentally, was the son of Maxim gun inventor Hiram Stevens Maxim) is credited with inventing and selling the first commercially successful suppressor around 1902 (patented 30 March 1909). Maxim gave his device the trademarked name Maxim Silencer and they were regularly advertised in sporting goods magazines.  Interestingly, the muffler for internal combustion engines was developed in parallel with the suppressor by Maxim in the early 20th century, using many of the same techniques to provide quieter-running engines. (Note that in many English-speaking Commonwealth countries automobile mufflers are still called silencers).  They were ubiquitous. Indeed, President Theodore Roosevelt was known to purchase and use Maxim Silencers on many of his firearms.

 

When a firearm is discharged, there are three ways sound is produced. Part of it can be managed but some of it simply cannot be eliminated.  The three ways a firearm generates sound are:

 

  • Muzzle blast (high temperature, high pressure gases escaping after bullet)
  • Sonic boom (sound associated with shock waves created by an object exceeding the speed of sound)
  • Mechanical noise (moving parts of the firearm)

 

A suppressor can only impact the noise generated by muzzle blast and sonic boom (and, in most cases only the former).  While the use of subsonic ammunition can negate the sonic boom, mechanical noise can be mitigated but is nearly impossible to eliminate. For these reasons, it is difficult to completely silence any firearm, or achieve an acceptable level of noise suppression in revolvers that function under standard operating principles. (The gas escaping from the gap between the cylinder and barrel contributes to the blast noise.)  Some revolvers have features that enable suppression, such as the Russian Nagant M1895.

 

Muzzle blast generated by gas escape is directly proportional to the amount of propellent contained within the cartridge. Therefore, the greater the case capacity the larger muzzle blast and consequently the more efficient or larger the suppressor required.

 

The suppressor is typically a hollow metal tube manufactured from steel, aluminum or titanium and contains expansion chambers. The device, typically cylindrical in shape, attaches to the muzzle of a firearm.  “Can”-type suppressors (so-called as they often resemble a soft-drink can), may be detached and attached to a different firearm.  Another type is the “integral” suppressor, which consists of an expansion or chambers surrounding the barrel. The barrel has openings or “ports” which bleed off gases into the chambers. This type of suppressor is part of the firearm (thus the term “integral”), and maintenance of the suppressor requires that the firearm be at least partially disassembled.

 

Both types of suppressors reduce noise by allowing the rapidly expanding gases from the firing of the cartridge to be decelerated and cooled through a series of hollow chambers. The trapped gas exits the suppressor over a longer period of time and at a greatly reduced velocity, producing a significantly diminshed noise signature. The chambers are divided by either baffles or wipes. There are typically at least four and up to perhaps fifteen chambers in a suppressor, depending on the intended use and design details. Often, a single, larger expansion chamber is located at the muzzle end of a can-type suppressor, which allows the propellant gas to expand considerably and slow down before it encounters the baffles or wipes. This larger chamber may be telescoped over the rear of the barrel to minimize the overall length of the combined firearm and suppressor, especially with longer weapons such as rifles.

 

Suppressors vary greatly in size and efficiency. One disposable type developed in the 1980s by the U.S. Navy for 9 mm pistols was 5.9” long and 1.8” in outside diameter, and was designed for six shots with standard ammunition or up to thirty shots with subsonic (slower than the speed of sound) ammunition. In contrast, another suppressor designed for rifles firing the powerful .50 BMG cartridge is 20” long and 3” in diameter.

 

Now that we know what suppressors are and how they work, let’s look at them from a strictly quantitative perspective.

 

To begin with, the power or intensity of sound is measured in decibels (dB). With reference to acoustics, a decibel is commonly used as a reference to quantify sound levels relative to the threshold of average human sound perception, or 0 dB. That’s thing one.

 

Thing two is that the average suppressor dampens sound by about 30 dB, and an exceptional suppressor will diminish the intensity of sounds by as much as 43 dB.

 

That’s good, right? The answer is that you don’t have enough information to make an assessment. Yet.

 

Thing three is a bit of data from which to make the assessment:

 

  • Normal conversation, taking place about one meter away is about 50 dB;
  • A passenger car driving by around ten meters away is about 70 dB;
  • A jackhammer operating one meter away is about 100 dB;
  • Threshold for risk of hearing damage is 120 dB;
  • Pain threshold is 130 dB;
  • .45 ACP pistol being fired one meter away is about 157 dB; and
  • 9x19mm (9mm NATO) pistol being fired one meter away is about 160 dB.

 

What’s it all mean?

 

It means that even if you have one of the super-duper, highly efficient suppressors that reduces sound level by 43 dB for your character’s 9x19mm pistol – from 160 dB to 117 dB, the gunshot’s report is still significantly louder than a nearby jackhammer.

 

(And that’s LOUD, folks!)

 

Add into the mix the mechanical sound of the pistol’s moving parts and the sonic boom created by the bullet as it breaks the sound barrier and things aren’t very stealthy. At all.

 

The question then becomes “If a suppressor doesn’t silence the sound, why use it at all?”

 

There are a number of answers, but essentially they boil down to:

 

  • The suppressor minimizes the pistol’s report;
  • The suppressor changes the sound so that it is less recognizable as a gunshot; and
  • The change in sound pattern caused by the suppressor helps to disguise the shooter’s location.

 

So, while suppressors most emphatically do not “silence,” they do provide valuable acoustic camouflage for the shooter.

How do I like my suppressors? Shaken, not stirred, of course.

***

Have your characters used suppressors-slash-silencers? Do you need Adam to go into more detail on anything he mentioned?

On Monday, MAGGIE TOUISSANT discusses how pacing can make or break your story.

***

Bio: Adam Firestone brings more than 25 years of experience with weapon systems including small arms, artillery, armor, area denial systems and precision guided munitions to Romance University. Additionally, Adam is an accomplished small arms instructor, editor, literary consultant and co-author of a recently published work on the production of rifles in the United States for Allied forces during the First World War.

Adam has been providing general and technical editing services to authors and publishing houses specializing in firearms books since the early 2000s. Additionally, Adam provides literary consulting services to fiction authors including action scene choreography, technical vetting and technical editing. In this line of experience, Adam has had the fortune to work with well known authors including Shannon McKenna and Elizabeth Jennings.

Check out Adam’s blog here: http://adamfirestoneconsultant.blogspot.com/

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Discussion

5 Responses to “Silencers, don’t. By Adam Firestone”

  1. Your posts always shake up my thinking, Adam. So I guess all those TV shows that show a gun being silenced with a cute little throw pillow are full of hot air, right?

    Posted by Becke Martin Davis | September 12, 2014, 3:06 am
  2. Morning Adam!

    lol, I’m with Becke…I swear one tv show had the gun silenced with newspapers? and of course we’ve all seen the throw pillow trick. Well, I guess that all proves why you’re our firearm expert doesn’t it? lol…

    Thanks Adam…your posts are ALWAYS informative!

    carrie

    Posted by Carrie Spencer | September 12, 2014, 9:19 am
  3. I talked to Adam awhile ago and he said a pillow would absorb some of the gasses released, so it would somewhat soften the sound of a shot.

    Thanks, Adam!

    Posted by Becke Martin Davis | September 12, 2014, 2:19 pm
  4. Hi Adam,

    I’ve seen movies when there’s a sniper in a hotel room. I know it probably depends on the type of rifle he’s using, but if he had a suppressor for it, could someone in the next room hear the shot?

    I always learn something from your posts. Thanks again!

    Posted by Jennifer Tanner | September 12, 2014, 11:38 pm
  5. If they weren’t watching us berofe, I doubt they’d notice an electronic signature There are already a million little points of light for the Orwellians to take interest in, from my voter registration, to my Carry permit(s) to my constant use of the NICS system to my blog, and references to myself with other blogs.Hell its even possible my conversations with friends via phone and email are getting sniffed.Either they know I’m here or they don’t. Also even if I’m on a list, there are so goddamned many of us, what are they going to do about it?

    Posted by Pitu | November 24, 2015, 11:01 pm

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