Siege
Dec 5 2003, 06:15 AM
HMHVV Hunter
Dec 5 2003, 06:21 AM
Yeah, I read somewhere that a suppressed gunshot can be as loud as a dictionary being dropped onto a hardwood floor.
Admittedly, that was from the Call of Cthulhu rulebook, but still it's interesting.
Though that car door beign slammed sounds like a pretty good reduction in sound.
(BTW I am neither military nor police, so I have no firsthand knowledge of this stuff).
Dim Sum
Dec 5 2003, 06:54 AM
The "clatter of the bolt" is sometimes eliminated by spec forces or spies (oo-er!) by arresting the weapon's bolt preventing its return slide. However, this is really only useful if you intend to fire single shots since the bolt must be manually released after each shot to chamber the next round.
Kagetenshi
Dec 5 2003, 07:40 AM
Woo for slide locks.
~J
durthang
Dec 5 2003, 10:22 AM
This also raises the question of how quiet do you really need to be? Chances are anyone close enough to hear the movement of the bolt will notice the shooter through other means as well (movement, the bullet hitting the target, etc…).
Crusher Bob
Dec 5 2003, 10:29 AM
The main advantage with the slide lock is that the cycling of the bolt is a vary 'non-innocent sound' while someone just walking around isn't.
Austere Emancipator
Dec 5 2003, 12:28 PM
QUOTE (Dim Sum) |
The "clatter of the bolt" is sometimes eliminated by spec forces or spies (oo-er!) by arresting the weapon's bolt preventing its return slide. |
SpecForces, spies
and every Finnish grunt that happens to have a sound suppressor if they so wish. In many gas actuated weapons, like the
RK95, you can simply shut the gas valve and don't have to lock the slide.
The bullet hitting the target won't tell you
where the shooter is, the noise of the bolt or slide will. Sure people will notice that somebody shot someone, but when they can't hear any sound from the shooter's direction, they haven't got much to go by as long as the shooter is well hidden.
I'll go ahead and advertise
Raygun's suppression-stuff too.
Cray74
Dec 5 2003, 01:16 PM
QUOTE (Dim Sum) |
The "clatter of the bolt" is sometimes eliminated by spec forces or spies (oo-er!) by arresting the weapon's bolt preventing its return slide. However, this is really only useful if you intend to fire single shots since the bolt must be manually released after each shot to chamber the next round. |
Interesting article. I know there is a single type of silenced revolver produced by the Russians, but it used unusual cartridges and (maybe) other design features to seal that gap.
Speaking of clattering bolts, it would seem like there's other ways to silence that than to lock the bolt between shots and require manual cycling. Unfortunately, I don't know where the impact surfaces are inside a gun to be more specific, but...
How about "rubberized" impact coatings? Even a thin coat of a high-temperature rubbery material (silicone, teflon) will do wonders for reducing the noise of metal hitting metal. Gun nuts: Are the striking surfaces in weapons usually directly exposed to burning gunpowder? Do they regularly get above 600F?
Also, (non-polymer) composite materials are good for soaking up sound. Carbon-carbon composites, ceramic matrix composites, metal matrix composites, cermets, etc. just don't "ring" like pure metals. All those reinforcing fibers and different components have different speeds of sound, so the noise gets fuzzed out into duller "clacks".
Pavlov
Dec 5 2003, 02:06 PM
I know Raygun's site provides a lot of rules for suppressors, but is there any chance subsonic ammo will make it into canon? Or, for that matter, rational suppression rules?
Siege
Dec 5 2003, 03:03 PM
QUOTE (Pavlov) |
I know Raygun's site provides a lot of rules for suppressors, but is there any chance subsonic ammo will make it into canon? Or, for that matter, rational suppression rules? |
I kinda doubt it -- although I wouldn't have thought they'd put that much mind-numbing effort into cyberware, decking and rigging.
Stranger things have happened.
-Siege
Mr. Man
Dec 5 2003, 07:47 PM
Interesting article. Since the UK gun laws are so strict compared to the US I always just assumed that silencers were illegal there as well.
Siege
Dec 5 2003, 08:37 PM
QUOTE (Mr. Man) |
Interesting article. Since the UK gun laws are so strict compared to the US I always just assumed that silencers were illegal there as well. |
Truthfully, so did I and I live here.
I know there's a company in Georgia that makes and sells silencers, but I've never felt the need to inquire further. Temptation is not a good thing.
-Siege
Adarael
Dec 5 2003, 11:50 PM
Well, for the most part, silencers are restricted, but not illegal - though some states, such as my beloved home (California) restrict them so much so as to be effectively illegal.
Most places, you need a concealed gun permit to have a silence. Others, you need a concealed gun permit AND a silencer permit. In California, New York (and one or maybe two other states - two at the most) you need to be some sort of law enforcement or law-enforcement accredited individual to have a silencer. This usually includes retired police or sheriffs' officers, certain private security companies (such as those that do site security for military storage spaces, or Raytheon).
Shadow
Dec 6 2003, 12:27 AM
Or you could live in Alaska, and carry a firearm concealed without so much as a background check. No licence required. Ah living on the frontier, to bad the weather sucks.
Purchasing a silencer is a lot like buying a class III weapon. You have to jump through some hoops, but you can do it. God Bless America!
FlakJacket
Dec 6 2003, 12:29 AM
QUOTE (HMHVV Hunter) |
Yeah, I read somewhere that a suppressed gunshot can be as loud as a dictionary being dropped onto a hardwood floor. |
Speaking of shotguns, would there be any difference if you were holding the muzzle up against someone when you fired? I read something about his the big bloody hole you make in the person could act as a kind of suppressor baffle. Anyone know if there's any truth in this?
QUOTE (Cray74) |
Interesting article. I know there is a single type of silenced revolver produced by the Russians, but it used unusual cartridges and (maybe) other design features to seal that gap. |
moosegod
Dec 6 2003, 12:34 AM
Link don't work.
FlakJacket
Dec 6 2003, 12:37 AM
Out of bandwidth. Try again later. Says so on page.
Game2BHappy
Dec 6 2003, 12:52 AM
Not sure if this is similar to the unavailable page, but here's another link to the
Nagant Revolver
FlakJacket
Dec 6 2003, 01:51 AM
Much better. Has pictures. Thanks.
Austere Emancipator
Dec 6 2003, 02:02 AM
QUOTE (Shadow) |
Purchasing a silencer is a lot like buying a class III weapon. You have to jump through some hoops, but you can do it. God Bless America! |
Weeelll, you can get sound suppressors for just about any firearm without any hassle whatsoever here in Finland -- except of course for the basic hassle of getting the firearm in question in the first place. So I guess Finland is more Blessed.
Cray, I guess we'll have to wait on Raygun to appear, unless one of those "post once and never reappear" gun nuts show up. I really don't know what parts of a firearm make most of the noise, and how hot those get. I'm sure there are some parts in there that could be coated that won't get very hot (like the extreme back end of the upper receiver, where the recoil spring and the end of the slide assembly is located), but for the rest of them I just don't know.
Raygun
Dec 6 2003, 06:42 AM
As Aus previously mentioned, my own website has much more information regarding
firearm sound suppression if you're interested in the details.
If you want to hear what a suppressed firearm really sounds like, there are videos available on the
OPS, Inc. and
SWR websites. There is also video of the
MP5SD being fired on the HKPRO website. If you've ever played
Rogue Spear, you'll recognize that sound.
QUOTE (Cray74) |
How about "rubberized" impact coatings? Even a thin coat of a high-temperature rubbery material (silicone, teflon) will do wonders for reducing the noise of metal hitting metal. Gun nuts: Are the striking surfaces in weapons usually directly exposed to burning gunpowder? Do they regularly get above 600F? |
It depends on the type of operation. The surfaces that contact each other are at the rear of the receiver, where the bolt/bolt carrier's rearward motion terminates, and at the forward part of the receiver, where the bolt is closed shut.
The sound at the rearward point of impact can easily be dealt with in some weapons using a
recoil buffer. Just a formed piece of polymer that sits at the rear impact point, between metal surfaces. There's no significant heat generated at that point.
The forward point of impact is much trickier. Not only is heat an issue, especially with automatic weapons, but the most common type of operation employed for automatic rifles, gas operation, uses a rotating bolt that locks either directly into the barrel or into an extension behind the chamber that essentially acts as a heat sink for the barrel. This rotating bolt locks the chamber closed until the bullet has left the barrel, so that pressure drops to a safe level before the cartridge case is extracted from the chamber. In other words, it keeps the rifle from blowing up in your face.
However, the majority of the sound generated at the forward point is usually by the bolt carrier impacting the forward part of the receiver. I'm sure that there are ways to make that forward "whack" quieter, especially if the weapon is purpose-built rather than retrofitted for quiet operation. Other types of operation and specific weapons may be easier to work with. Al Paulson suggested machining an annular ring at the rear of the barrel and around the chamber of the Ruger 10/22 (blowback operated), which would then be filled with a rubber O-ring commonly available at plumbing stores. Of course, this only applies to one specific model of firearm (a .22 at that), but it's an interesting idea. Still, the simplest way to keep cycling noise from being a factor is to just lock the bolt closed and cycle manually.
All of this is really academic anyway, as the act of shooting things with automatic weapons is going to be given away by the sound of the bullets impacting the target (area), no matter what they're made of. It's pretty difficult to diguise that sound, whether it be bullets tinking off of a car, or impacting a road, a lawn, water, or flesh. If you've ever gone hunting, you know what I'm talking about in the latter case. That suprisingly loud "THIP" sound that says "good job". The good thing is that that sound is usually louder than the cycling noise and it also has a tendency to draw attention away from the shooter's position.
Cray74
Dec 6 2003, 03:30 PM
Thanks for that informative input. That did help my mental model of gun noise.
QUOTE (Raygun) |
All of this is really academic anyway, as the act of shooting things with automatic weapons is going to be given away by the sound of the bullets impacting the target (area), no matter what they're made of. |
Ah, well now. I was thinking of a silenced weapon in terms of "not finding the shooter" instead of "hiding the fact that shooting is occurring." If I want to hide the shooting, I'd try to use 1 bullet to get the job done and then run.
So, is it easy to ID where the shooter is (assume shooter is 50-100m away) if all you have to go on is a hail of bullets making a lot of noise in your area?
Raygun
Dec 7 2003, 12:59 AM
QUOTE (Cray74) |
So, is it easy to ID where the shooter is (assume shooter is 50-100m away) if all you have to go on is a hail of bullets making a lot of noise in your area? |
It depends on whether the shooter is trying to hide or not and what kind of environment he and the target are in at the time. In general, I guess the sound at the shooter's position will probably not be recognized as a gun by the vast majority of people, especially in urban environments. But out in the sticks, even suppressed, the sound would be undeniably mechanical and much more noticeable. It's the regular, repetitive sound of autofire that gives it away, which wouldn't be a factor with precision fire.
Basically, there's not a lot of point in suppressing autofire other than to protect the shooter's hearing, especially in close quarters. Stealthy precision fire is much more effective.
Eindrachen
Dec 7 2003, 02:55 AM
Another factor is that people assume you can just know instantly where a shot came from. At long range, that might be true, but in a closed environment (hilly forest, or urban area with lots of tall buildings/structures), that echo sucks. At a certain distance, it sounds like it's coming from everywhere.
And yeah, out in the country, the sound of a gunshot is very distinctive to most of those living there; most of us grow up with it. There are a few folks who are so into the gun hobby out here, they can tell the gun being shot, and, if they know the person's shooting habits (timing between shots, location being hunted, etc.), they can tell exactly who's hunting and where they are.
To jump back to the gas-vent comment, I wonder how feasible it is to make a combo gas-vent / suppressor? Certainly sounds nifty...
Raygun
Dec 7 2003, 03:18 AM
Completely infeasible. A suppressor is designed to contain, slow, and reduce the pressure of expanding propellant gases (the cause of the bang) while a compensator uses that energy (most effectively without reducing its pressure or velocity) and redirects it to counter muzzle climb. It is possible to machine a muzzle brake into a barrel and then have a suppressor mount over it when needed. But in reality, suppressors are more often than not just as efficient at controlling recoil as "gas vents" are, so having both is generally superfluous.
More reading.
Diesel
Dec 7 2003, 09:56 AM
I don't mean to be retarded, but how exactly does a muzzle brake work?
I read about them a half dozen different times today looking at rifles and it was "nod the head, pretend you know" sorta thing. Do tell. Thanks.
Austere Emancipator
Dec 7 2003, 12:34 PM
I'll have a go at a semi-sensible answer for you to go with until Raygun comes back:
A muzzle brake generally speaking includes metal plates at an angle of 90 to 135 degrees to the barrel. Often there's a bit of space after the barrel ends before the metal plate(s), a sort of chamber.
The muzzle brake you can see on most Barretts has two separate metal plates (Barrett calls it "dual chamber" muzzle brake) that extend quite abit from the sides of the barrel. I've never seen what's inside that thing, but I'm guessing the plates simply form 2 sides of a triangle but with a ~13mm hole at the apex for the bullet to go through.
As the weapon is fired, the bullet passes through the holes out of the muzzle brake as normal, but the gases start expanding into the chambers and then slam into the plates, getting deflected 90-135 degrees. In the Barrett muzzle brake, the gas that goes right after the bullet into the second chamber may then hit the plate there and get deflected.
I'm guessing the reason why this reduces recoil is that: A) The gases hitting the muzzle brake push the weapon forward, negating a part of the recoil. B) The gases that are deflected do not increase the recoil like they would have, since instead of coming straight out in front of the weapon, they now come out sideways -- or in the best case scenario, they come out slightly backwards, so that they actually push the gun forward.
And because of the slamming of the gas against the muzzle brake, and the deflection of the gas (and sound, I guess) back towards the shooter, it makes the gun a lot noisier to shoot.
But this is all pure hypothesis. I'm sure there's many things wrong in that, or at least a lot missing.
QUOTE (Diesel) |
I read about them a half dozen different times today looking at rifles and it was "nod the head, pretend you know" sorta thing. |
That's what I always do, nodding the head. I don't have a clue what many gun sites on the net are going on about, but I just keep reading through and hoping that some day it will all make sense to me...
Cray74
Dec 7 2003, 01:59 PM
QUOTE (Diesel) |
I don't mean to be retarded, but how exactly does a muzzle brake work?
I read about them a half dozen different times today looking at rifles and it was "nod the head, pretend you know" sorta thing. Do tell. Thanks. |
The muzzle break reduces recoil by redirecting muzzle gases.
Being slow and pedantic about it...
*Normally, the bullet and gunpowder gases go forward. Reaction: gun goes backward.
*With a muzzle break, there's a "gizmo" (some say it's widget, but IMO it's clearly a gizmo, or maybe a thingamabob) on the end that redirects the muzzle flashes backward. In other words, the muzzle blast is used kind of like a rocket to pull the barrel forward and offset some (not all) of the recoil.
Not only does this website have pictures, but it explains thing better than I did:
http://riv.co.nz/rnza/hist/ord/muzzle.htm
6thDragon
Dec 7 2003, 03:20 PM
Another thing to consider when discussing the noise a silenced weapon makes is the area the gun was fired in. If you're outdoors the noise will be less. If you're in an enclosed area the noise will reverberate off the walls (kind of like the blast in a confined space rule from the main rulebook). I remember when I was in the Marines, I was in a stairway in a building under construction and a 12-gauge went off. Wow, was that loud! There was no carpeting or anything to absorb the sound. But then again you can't exactly silence a 12-gauge.
Raygun
Dec 7 2003, 06:58 PM
Exactly. The environment you're shooting in makes a lot of difference in how effective firearm suppression can be. Firing a suppressed firearm in an urban environment is more effective because the sound will likely be dismissed for other, more common mechanical devices such as jackhammers, car mufflers, the general noise of construction sites, etc. In rural or wilderness areas, it is much more difficult to diguise that sound for the obvious reasons.
The sound of a gunshot definitely is louder in close quarters environments due to reverberation. Here is an example of that. Earlier I posted a link to a video of some guys firing
MP5SDs outdoors. Here's a video of a guy firing a suppressed
UMP45 indoors during CQB training. Obviously the camera is a little closer to the UMP shooter, but the suppressor he's using is more efficient than the MP5SD's. Still, the shots seem much louder because of his environment.
As for muzzle brakes, here's an up-close picture of a dual-chambered
OPS, Inc. muzzle brake mounted on a sniper rifle. They really are very simple devices, and they do work in the way that both Aus and Cray have explained. Propellant gases are simply redirected in a way that negates the rearward motion of the rifle by using the energy of the muzzle blast to push the rifle away from the shooter's shoulder.
Dim Sum
Dec 8 2003, 06:37 AM
QUOTE (durthang) |
This also raises the question of how quiet do you really need to be? Chances are anyone close enough to hear the movement of the bolt will notice the shooter through other means as well (movement, the bullet hitting the target, etc…). |
You won't believe how many cliched methods of assassination are still in use today which would require near absolute silence from a gun or at least a sound that doesn't sound like a gun (although the first is, of course, by far the more preferred choice). As recently reported as the 1980s, a bank manager was killed by an assassin who walked into an office with an appointment to see their target, shot the manager with suppressed pistols without anyone outside being the wiser and simply walked out again. Police later recovered a .22 silenced pistol with the slide modified to lock it back after each shot.
Other cliches include the gun in the folded newspaper thang, which still remains in use in the Middle East.
Some magazines/journals carry articles about such incidences.
Funny thing, of course, is that I've yet to see anything like this in a Hollywood movie.
Diesel
Dec 9 2003, 06:12 AM
Thanks all!
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