An Introduction to Weapon suppressors and silencers.

Ben Broughton via google ^ | 2000 | 2000 Ben Broughton

[Octar]

Bump

[MadRobotArtist]

The internal combustion engine makes noise because each cylinder houses a small explosion which drives the cylinders down, which in turn powers the car, and makes it go. The exhaust you hear are those little explosions. The tailpipe, and muffler keep it quiet. It has nothing to do with velocity or any of that.

[MadRobotArtist]

My wife is a gaming geek, and we actually have this book. The majority of the stuff in it is crapola, but you can find some nuggets of truth in it.

[AAABEST]

When I was stationed at Ft. Benning, we did a lot of range duty. Many days in a pit changing targets.

Good training to be on the receiving end of weapons fire.

[elmer fudd]

The supersonic crack of bullets overhead is loud, as loud as a child's cap pistol. Also, you hear it before you hear the sound of the muzzle blast.

Suppressors and sonic booms are an interesting subject. You hear a sonic boom relative to what it passes, not from where the bullet came from. Basically you'll hear it crack when it passes you, and you'll hear the echo of it's boom as it passes other objects. You still hear a gunshot, but it doesn't sound like a gunshot and you can't pinpoint it's origin. Silencers are also much more effective outdoors than they are inside. I'm not exactly sure why that is, but it's true.

[elmer fudd]

I fooled around once shooting arrows out of a double barrel shotgun. I'd only use a little powder and I used two wads, one in the cartridge and one at the base of the arrow immediately after the chamber. When you got the powder charge just right you could launch the arrows at about 500 fps and in almost total silence. I probably could have perfected it if I had had reloading equipment. As it was though I was measuring my powder charge with an old .22 casing and cutting open shotgun shells with a carpet knife and it was hit or miss. Sometimes the arrow would barely make it out of the barrel and other times it sounded like a .45.

[Squantos]

There used to be a barrel one could buy that fit a ruger 10-22 and Model 77/22 that allowed a standard easton aluminum arrow without the fletching to be fired in total silence using a small .22 blank like the ones used in the power drivers/hammers. It had a small barrel within a barrel....was real quiet

I have looked for one of those but they seem to have quit making em.

Stay Safe and thanks for the info.......

[Joe 6-pack]

"You ain't been corking off that M256 in a residential area again, have you, Joe? ;-)"

What? who? Me? Naaaah....

[xm177e2]

The supersonic crack of bullets overhead is loud, as loud as a child's cap pistol.

Also, you hear it before you hear the sound of the muzzle blast.

Can you still tell the direction it came from, or is that much more difficult when the weapon is suppressed?

[HP8753]

Or you can just use some CB's... .22 ammo made for indor shooting by CCI.
750ft /sec w/ 29 grain bullet.

The CB's used with a bolt action rifle are quieter than my pellet gun.And you can see the bullet going down range.Packs more punch than my pellet gun does also.

CCI CB AMMO

[2nd_Amendment_Defender]

Why is it we are only good enough citizens to own suppressors if you pay a 200 dollar tax.

When did these regulations start by the B.A.T.F. ?

[ctdonath2]

1934, with the National Firearms Act (NFA). All downhill from there.

[sit-rep]

bttt

[spunkets]

" a car without a muffler?"The velocity of sound in air is about 1125ft/sec. The velocity of the gases exiting a gun following the bullet is ~3000 ft/sec. Whether it's black, or smokeless powder that velocity doesn't change much and can be used to calc. recoil from conservation of momentum.

In an IC engine the cam opens during the power stroke. ~7-15in into the pipe, depending on the cam, the the flame temp is about the same as a rifle shot. If the pipes are ~20in, as on a dragster yellow flames fly out, the sound is definetely supersonic at ~<3000ft/sec. Otherwise with full pipes, it then decreases rapidly as it goes through the pipe.

Headers and the stock cast manifolds are setup so there's a reverberation in the tubes so the momentum of the exit gases leaves a lower than atmospheric pressure in the cylinder. That condition then exists when the intake valve opens. That causes a higher velocity during cylinder filling. There's some overlap in valve opening, so intake mix is going out the exhaust pipe. The exhaust pulse spreads backward quickly and shoves what mix is in the exhaust pipe back in the cylinder before the exahust valve closes. That backward pulse is quite a bit lower temp and corresponds to the slowing wavefront. The longer the pipe the slower it goes at the exit.

At any rate, if the sound has a definite crack w/o a muffler and sounds more like an airplane engine, it's supersonic. If it's a booming rumble it's subsonic.

[boris]

"the sound is definetely supersonic at the ~<3000ft/sec.

I don't know what you meant to say, but what you did say is nonsense.

--Boris

[boris]

Sorry, a spurious "the" crept into the quote.

Still nonsense without the "the".

[spunkets]

What I meant is the wavefront is at 3000ft/sec. The speed of sound is ~1100ft/sec.

[Gil Lindsey]

Great read. I would also stress the importance of the cleaning ritual with respect to matter forced back into the chamber due to backpressure from the suppressor, I own a semi-auto Ruger Mk.II with a Hammerli barrel liner and a Bentz chamber. This piece is very prone to extraction and ejection problems possibly because of the tight chamber, if not kept spotless (as all firearms should be kept!). However, with a VERY EFFICIENT integral suppressor, the debris is forced back into the chamber,evidently as the pressure curve drops off, as I realize no "breech pop". The same level of efficiency in a suppressed bolt action action rifle with a "factory" chamber does not seem to need as much attention. Needless to say, both require cleaning after a long day at the range, but the semi is more demanding. A solution I use is 90% Kroil and 10% G.M. Top End engine cleaner. After I remove the bolt with the "speed strip" conversion, I use a soft rubber plug in the muzzle of the suppressor, suspend it vertically, muzzle down, and fill the integral unit to the chamber. It loosens the crud, and I clean the lower unit as usual. The "speed strip" kits makes all of this a short task. I think we all would agree that extreme accuracy and reliability comes with a price, but with suppressed weapons the cleaning cycles can be very short. I feel the trade off is worth it. I also use lithium grease as an ablative material in the rear chamber, though the integral unit is extremely impressive without it (110-113db) because the manufacturer emphasized the benefit of a grease getting into all of the nooks and crannies sometimes occupied by moisture and corrosive elements. I will be happy to share with you the manufacturers of my units, as I have seen many, yet none finer. E-mail me and I'll give you the addresses.
Gil
gillindsey@hotmail.com