Suppressed Guns & Better Mousetraps

Silenced Makarov

Silenced Makarov

Suppressors/silencers have been around a long time.  There are many reasons to lower the noise signature of a gun, some tactical, some practical. And there are some disadvantages to it as well.

As a general rule: pillows, soda bottles and other improvised field-expedient measures are not effective, and usually not practical either.  There’s a pretty good article covering the subject of suppressors here.

(click the title for more)

The principles are simple.  A gun creates (potentially) 3 kinds of noise when it is fired: the mechanical sounds of the gun being fired and cycled, the muzzle blast of gasses that follow the bullet out of the barrel, and (in the case of high velocity ammunition) the sonic boom of the bullet as it breaks the sound barrier.  How do you quiet it down?

In the case of the mechanical sounds, there’s not much you can do.  Some guns are quieter than others.  A revolver makes more mechanical noises before firing than, for example, a 1911 or a Glock.  But it also doesn’t have to cycle a slide, which makes noise.  If you suppress a single-shot or bolt-action gun, you can make it VERY quiet in operation.  Examples: the Welrod pistol and the DeLisle carbine:

Welrod pistol and DeLisle carbine

Welrod pistol and DeLisle carbine

For the muzzle blast, you find a way to contain or slow down the gasses that follow the bullet out of the barrel.  Some suppressors use water or lithium grease to increase the sound deadening capability.  Here is an X-ray of some suppressors:

X-ray view of suppressors

X-ray view of suppressors

It’s not rocket-science; just re-direct the gas and slow it down until it doesn’t make a loud noise.  A revolver will allow some gas to escape through the cylinder/barrel gap (except the 1895 Nagant with its gas-sealing feature and the heavy trigger it requires to operate; Crapgame calls mine the “hand exerciser”).

As to the sonic boom of supersonic bullets, you have 2 options: use a subsonic cartridge (like the .32acp Welrod and .45acp DeLisle), or use a regular supersonic cartridge and bleed off gas from the barrel to reduce its velocity below the speed of sound. The HK MP5SD uses this technique to allow any 9mm ammunition to be used in the gun without compromising the level of sound reduction.

Actually, there’s a 3rd option: use it with supersonic ammo, and cause a lot of confusion among the people you are shooting at, since the sonic boom will make them think the bullet came from the opposite direction that you shot from.  This is really only practical with a rifle, at medium to long range.

The disadvantages of a suppressed gun are: increase in weapon size, radical altering of the gun’s balance, potential of obscuring the gun’s sights with the suppressor, lowered velocity/lethality (if the weapon bleeds off gas), reduced cycle reliability, potential of a bullet striking the suppressor if the alignment isn’t exact, and the suppressor collects dirt and can send it back into the action.

But all of that presumes you are starting with commonly-available guns and ammunition, that you must adapt to suppressed use.  If you modify a gun, you can reduce some of the drawbacks of a suppressed weapon.  For example, the silenced Makarov at the top of this post.

Here is where things get weird.  If you start with the premise of a suppressed gun and think outside the box of commercially-available guns and ammunition, you can potentially build a better mousetrap.  During the Vietnam war, there was an experimental American program to develop special silenced weapons for use by tunnel rats and special operations personnel.  The result was the Quiet Special-Purpose Revolver (QSPR):

Quiet Special-Purpose Revolver

Quiet Special-Purpose Revolver

It was 10mm/.40 caliber, and fired a special shotgun ammunition, with a steel casing and a plug that blocked the end of the casing when it was fired.  The ammunition contained 15 tungsten balls weighing 7.5gr inside a sabot, and reached 730fps for a terminal energy of 135 ft/lb.  Estimated lethal range was 30 feet, and the noise level was reported as 110db.  I don’t know what happened to the gas inside the shell after it was fired; I guess it slowly leaked out.

The Russians took this concept and went considerably farther with it.  They wanted an improvement over their PB/6P9 silenced Makarov pistols.  They took the 7.62×39 cartridge and loaded less powder into it, and put a collapsible piston behind the bullet, which would push the bullet out of the barrel and block the casing:

PZAM-1 and SP-3 ammo

PZAM-1 and SP-3 ammo

They made 2-shot derringer-style pistols to fire these rounds (the MSP and S4M), which were apparently very quiet.  Only 2 shots, because the protruding piston would prevent a pistol from ejecting and a revolver from spinning.

UPDATE: an article about the MSP which includes a link to the actual manual!

MSP pistol and SP-3 ammo

MSP pistol and SP-3 ammo

This was not a great solution.  So they improved the ammo by using a shorter single-stage piston and a 143gr flat-nosed mild steel bullet with a brass driving band to reduce the overall length.  This new ammo, called SP-4, could be chambered in a revolver or a self-loading pistol and still cycle.

SP-4 ammo; unfired and fired

SP-4 ammo; unfired and fired

The Russians designed two handguns to use this ammo.  One was the PSS-1 and PSS-1a pistols.  6-round capacity, with a unique 2-part barrel (the forward part was rifled, and fixed to the frame):

PSS pistol

PSS pistol

They also made a revolver to fire the SP-4 ammo (presumably, to eliminate any spent brass getting left behind when they assassinate someone;  they are probably working on a way to silence a Tupolev airliner for the next time they want to wipe out the government of one of their uppity former satellites).  It is called the OTS-38, and it has an “integral” laser sight:

OTS38 revolver

OTS38 revolver

I use the word “integral” in parentheses because the Russians have not yet learned to translate or factor in ergonomics when they build things.  The switch for the laser is that tacked-on looking horizontal plate angled out, behind and above the trigger in the left picture.  The OTS38 is fed with 5-round full-moon clips, and the cylinder swings out to the side.

Both the PSS and OTS38 are apparently very quiet.  Not great fighting guns, but they were designed from the ground up as silent guns.  And in design, you can never create something that does all things well.  Better technology and materials can widen the possibilities, but those are not Russian strengths.

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2 Responses to “Suppressed Guns & Better Mousetraps”

  1. GraniteGal says:

    [Disclaimer: I am GunNutmegger’s sister]

    Hi GunNutmegger & Crapgame,

    NOW I understand what GN was doing driving around CT with CG all those days. Thank you for the excellent website and all the work you have both put into it.

    When you are ready for a field trip to the Granite State, I’ll bring you to “Ladies Night” at one of my local shops w/range. Perhaps you gals would like to give the M2 .50 cal or the M60 .308 a spin?

    Here’s the shop + range closest to you for a day trip (~3h 15m from your location):
    http://www.gunsnh.com/pictures.php

    If not a day trip, you gals can spend the night on my put-you-up and visit some seriously-equipped shops. We even have a Five Guys now! 😉

    Live Free or Die, ladies.

  2. crapgame says:

    Hi GG – about time you stopped by for a visit. I’m sure that GN would be happy to shave his legs and put on a dress for a chance at shooting a Ma Deuce. 😉