I've been reading some of Robert Ludlum's spy novels, in which silenced handguns only go 'spat-spat' like in the movies. I know better than that, but there are still some outstanding questions in my mind.
Obviously silencers work better on smaller calibre handguns, it would be pretty difficult to shush a .44 Magnum. But do they work equally well on automatics and revolvers? Does an automatic's slide mechanism need to be locked closed or can it be allowed to operate without unwanted noise escaping? What about the credibility of silenced submachine guns like Uzis?
Well, on subsonic rounds, and not on revolvers, they work well.
Nope. There's a gap between the cylinder and the barrel on a revolver where quite a bit of gas escapes from, which makes a silencer ineffective. Depending on how well the revolver is made (and worn), that gap can be considerable, sometimes even spitting lead on an ill-timed revolver. Being next to a led-spitter is _not_ fun, let me tell you.
By the time the action opens on these, the pressure buildup has been released because the bullet is out of the barrel. Generally speaking and oversimplified. But, you don't have a blast of air coming out the back, which would be what makes noise. By the time the action opens, the pressure is relatively very low.
I was at a demonstration of a silenced H&K MP5, and the only noise was the clicking of the action cycling, and of the bullets landing in the target area. No bangs, no hiss, no nothing. Damned impressive. A uzi or sten with a silencer should be about the same - nearly no noise.
Supersonic rounds with a silencer - well, you'll get the sonic boom "CRACK!", so there's no point in lessening the noise of the muzzle blast. Gotta load 'em down to be effective. Maybe someday I'll buy the $200 tax stamp so I can get one of 'em...
I wondered about that. I've seen pictures of revolvers being fired that showed a considerable amount of blast coming out the sides.
Interesting...
I've heard that 'snap!' 'whump!' of bullets passing over the raised target and into the sand of the butts beyond many a time. It's not a noise the average civilian would identify as a gunshot, however loud it might be.
Yup, that's the noise. You're hearing the sonic boom, and the impact, without the muzzle blast (or, at say 600 yards, the muffled, much later muzzle blast).
I'm not sure about that; I've associated that noise with gunshots, but that's probably due to 30-some years of direct experience pulling targets. I would think that the average "never heard a real gunshot" person could reasonbly think that it was. But, either way, it's not "silenced" if the projectile is supersonic, as you noted in your example.
The science involved in silencers is pretty interesting.
The best gun to silence is a Luger because the chamber pressure drops to zero by the time the toggle opens. Don't ask me how I know this. Pffft! Pffft!
Depending on (insert vague hand-waving here), the muzzle blast might, or might not, be most of the sound of the gunshot. If you still get the sonic boom, you're still going to hear a loud noise that sounds like a gunshot...it just sounds a bit odd. Subsonic you just hear the mechanicals, which sound more like a sewing machine than anything else.
Ignoramus19430 wrote in news:d6vr0d $6s7$ snipped-for-privacy@pita.alt.net:
No, the two are not related.
The "silencer" [aka "sound suppressor"] _only_ deals with the gasses produced by the combustion of the propellant - and _then_ only as these gasses exit the barrel.
The "sonic boom" produced by a supersonic object's shockwave is independent of the motive source.
A classic example of this is a low-level pass by a "dead stick" fighter plane at a speed in excess of that of sound: there'll be a "sonic boom" even though there is no sound produced by its engine(s).
John, I am rather fortunate, because I had the opportunity to do a week long armorer's course at Heckler & Koch at their factory in Germany. In the process of this course, I dissassembled, reassembled and fired almost every weapon they make. This included 40mm grenade launchers, silenced pistols and submachine guns in 45, 10mm, 9mm, 5.56mm and the new 4.6mm MP7. In all cases the sound signature was reduced. The range I used had concrete walls, open at the roof and 25 meters long. There were 4 shooting positions. I was subjected to the muzzle noise, the supersonic crack when present and reflected noise from the side walls. In all cases, I still had to use hearing defenders except for the the silenced MP7 in 4.6. It is important to note that the 4.6 round was moving at 740 MPS which exceeds Mach 2. The supersonic crack was present, but only just. I was not impressed by any of the other silenced weapons including the MP5 and the SOCOM Mark 23 .45 for sound suppression. The silencers were all Swiss made. However, the MP7 and the 4.6mm was very IMPRESSIVE in all respects especially the terminal balistics in gelatin with and without class 4 body armor! Steve
From the point of view of a spy novel plot, I don't think the supression of all noise would be as important as the ability to disguise the distinctive sound of gunfire. In other words, you don't want people nearby to conclude they've heard a gunshot. If they hear a bullwhip like crack and a thump it's not as alarming. How were the silenced weapons from that point of view? What do you think someone would hear from the other side of a hotel room wall for instance? Would they shrug it off as a noise from the sound track of a TV cop show?
Like all things, there are trade-offs: no perfect solution (as of yet, anyway).
A suppressed firearm firing supersonic ammo does have two advantages over non-suppressed firearms. As already discussed, the gunshot often does not sound like a typical gunshot, so it *might* be mistaken for something else. Perhaps more importantly, even if the sound is recognized as a gunshot, it's very difficult for a person to distinguish the location of the shooter based solely on the supersonic report. The confusion may offer the shooter the ability to escape before his location is discovered.
From what I understand, some special forces have suppressed semi-automatic/automatic weapons that are modified so that the user can lock the action closed so there is no sound from the action cycling (thus, it would essentially be the same as firing a suppressed bolt-action rifle). Combined with sub-sonic ammo, these are very quiet weapons, yet can be returned to normal semi-automatic/automatic operation if needed.
The disadvantage of sub-sonic ammo is greatly reduced range and penetrating capability (which is why suppressed military weapons are typically in larger calibers). A fairly close-in head shot is typically required for a quiet one-shot kill. That's why this is the stuff of highly-trained special ops.
There are "silenced" M16s, which were in use by special forces in Vietnam. You can't kill the supersonic "crack" of the bullet but you can mask the muzzle noise. The effect is to disguise the direction from which the shot came. The "crack," without the "boom," appears to come from a generalized area rather than from a spot.
Huh? Could you elaborate on the "paraffin test"? Also, I've heard that a silencer will have an adverse effect on the action of, say, a M1911 (I think due to the weight on the barrel). Is this true? - not that I have any use for this knowledge.
Let the record show that John Ings wrote back on Tue, 24 May 2005 16:47:07 GMT in rec.crafts.metalworking :
"Silencers" for firearms are like "silencers" for automobiles (aka "Mufflers") - they both "trap" the combustion gases and allow them to expand to ambient pressure "inside" something, and thus exit the chamber in "a calm and orderly manner". In theory, you could make a silencer for a
105 MM Howitzer, but the people at the target aren't going to hear the discharge anyway. :-)
On automatics, the bullet has exited the barrel/ cum silencer before the chamber opens. Revolvers, except for one model Nagant, have a gap between the cylinder and the barrel (have to, in order to rotate the cylinder). The Nagant Revolver mentioned, has an interesting feature: when you pull the trigger, the cylinder moves up and seals against the barrel. "Way cool."
Silenced submachine guns - they work. Same principle as you would use for a pistol or a rifle. Problems supposedly develop with suppressed machine guns in "burning out the silencer". I don't know. Would probably depend on the internals of the silencer. I've heard of some cheapo silencer using steel wool to pack the cylinder to serve as baffles. "Works" but ... I've also heard of people being cleaver and packing their motorcycle exhausts with styrofoam. Works nice to muffle sound, till the whole thing gets hot. Tim said it was a sight to see - flaming globs of molten plastic spitting out the exhaust pipe into the night.
If you can muffle the muzzle blast, the next "sound" is the Crack of the bullet as it breaks the sound barrier. That can be "solved" with subsonic rounds, but slower rounds also lack punch and range. (Force is mass times velocity.) As for the noise of the action, well, not much can be done about that. And there isn't didly you can do about the noise the bullet causes at impact, be that just the mechanical sounds of it impacting the target, or the scream of the victim.
Its not so much the screams as the spasms, kicking, twisting and flopping around, followed by wet gasping. Head shots sometime result in the "fish out of water" flopping for a bit as well, as the autonomic nervous system shorts circuits.
Gunner
"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.
Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner
I hadn't thought of or read that, but it makes perfect sense. A M1911 (or any of the hundreds of other designs derived from Mr. Browning's genius invention) locks the barrel to the inside/top of the slide through a number of lugs - horizontal notches in each that interlock. When the barrel/slide recoils far enough, the link pin pulls the rear of the barrel down, which allows the slide to cycle fully back. This tipping would be more sluggish if the mass of that being tipped was much higher, as with a silencer or carbine barrel. (thinks...) It'd probably work but you might need a hotter load to move the additional mass, which is contrary to trying to stay subsonic. An intersting question...
I bet Julian Hatcher has played with that, but I don't remember anything specific.
The "paraffin test" is used to detect the residual nitrates produced by the combustion of the propellant powder.
A thin layer of melted paraffin [sp?] is applied to the hand (rather like they do at a beauty parlor) then peeled off and the portion that had been in contact with the skin is tested for nitrates extracted from the pores and/or the exterior of hairs.
Blowback-operated actions and revolvers will allow propellant gasses to escape. These gasses will carry microscopic amounts of particulate nitrates which will, then, be deposited on anything nearby - including the shooter's hand or hand covering.
No longer popular with TV writers, the test is still used by Law Enforcement.
FWIW, the Colt Woodsman, using target rounds, was a favorite of the OSS in WW2 when fitted with a silencer. [The barrel was fixed to the frame.]
There is a way to de-couple the extra mass of a silencer from a swinging barrel such as a 1911. I think one type is called a Nielsen Device which rides on a spring coupled bushing and can, for the brief time needed to unlock the barrel, fool inertia.
Somehow I'm not surprised that someone already fixed that problem. Thanks for the info! Thing is, I don't have a license for a can, so I haven't played with one, and I wouldn't put it on any of my 1911's in any case - one is a pre-A1, the other is a _nice_ commercial from the '60s that was redone by Charlie Milazzo (the trigger guy). Some things you just don't mess with, y'know?
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