How do suppressors work?


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ZeppelinM16
January 2, 2010, 12:47 AM
Can anyone shed some light or post a helpful link? Just curious, thanks!

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panoz77
January 2, 2010, 12:52 AM
IF your looking for advice on how to build one, my advice is don't, it's just a hair illegal without the stamp (see below).

They make the loud bang a gun makes less loud, they usually cost about $200 to $400 (for the actual harware) and are only able to be purchased after you pay the Feds $200 for a tax stamp and are apporved by your local LEO provided they are even legal in your state.

ZeppelinM16
January 2, 2010, 12:56 AM
Not looking to make one lol. Just curious.

David E
January 2, 2010, 01:05 AM
How do suppressors work?

Vewwy, vewwy quietly...............

pat86323
January 2, 2010, 01:33 AM
what a suppressor does is slow a bullet down to a speed less then that of the speed of sound. That way no sonic boom created by the bullet. Is that the answer you were looking for?

panoz77
January 2, 2010, 01:35 AM
NEGATIVE, on the bullet slow down "theory". To fully realize the potential sound reduction a suppressor is capable of you need to use SUBSONIC ammo, subsonic ammo is slower than the speed of sound to begin with, supersonic ammo is not slowed down below subsonic speed by a suppressor. A suppressor uses internal baffles to reduce sound. [and little rubber tires to slow down the bullet, the kind they use on roller coasters to slow it down at the end of the ride, only really tiny ones]

herohog
January 2, 2010, 01:38 AM
It works like the muffler on your car by using a series of baffles and chambers to break up the sound waves of a shot. To be effective, you use sub-sonic rounds with them or else you will still get that Crack as the bullet breaks the sound barrier. Sorry for all the non-High Road responses you have gotten. I am surprised no admins have spoken up.

Jorg Nysgerrig
January 2, 2010, 01:38 AM
I would start here. http://en.wikipedia.org/wiki/Suppressor
Here's another article: http://science.howstuffworks.com/question112.htm

pat86323
January 2, 2010, 01:42 AM
http://en.wikipedia.org/wiki/Suppressor yeah read up. They certainly do slow down the bullet, the boom that you hear is not the powder exploding it is the bullet breaking the sound barrier. I have taken some physics classes and such and believe me.....things that break the sound barrier are loud it takes immense amounts of energy to move an object faster then sound.

zombienerd
January 2, 2010, 01:54 AM
They certainly do slow down the bullet

Dude, I can't think of anything High road to say about this.. So I'll just say You're wrong... You're so wrong, you need to re-read the article you posted yourself.

Suppressors DO NOT slow down the round. They redirect the gases leaving the barrel and muffle the sound, that's it.

If you use supersonic ammunition, you still get the "crack" even with a suppressor... If you use subsonic ammo, you do not.

average_shooter
January 2, 2010, 02:03 AM
If memory serves, there were some old designs (perhaps Maxim?) that utilized rubber baffles that the bullet had to pass through and physically contact; however the intention of these baffles was not to actually slow the bullet, just slow the gasses. Same follows with more modern designs using all-metal construction though the bullet is not supposed to actually contact any of these baffles. The baffles inside the tube are designed to slow down the gasses produced by the burning powder, not the bullet itself.

REAPER4206969
January 2, 2010, 02:05 AM
WOW just WOW! http://www.ar15.com/images/smilies/smiley_freak.gif

pat86323
January 2, 2010, 02:06 AM
From the article that jorg posted........
"Several alert readers have written to point out that a bullet that travels at supersonic speeds cannot be silenced because the bullet creates its own little sonic boom as it travels. Many high-powered loads travel at supersonic speeds. The silencer can remove the "uncorking" sound, but not the sound of the bullet's flight."

from the wiki
"It generally takes the form of a cylindrically shaped metal tube with various internal mechanisms to reduce the sound of firing by slowing the escaping propellant gas and sometimes by reducing the velocity of the bullet.[1][2]"

its simple science, that is all.

scythefwd
January 2, 2010, 02:13 AM
Pat86323 - is not the bullet that is slowing, but the gasses escaping behind it. By increasing the area in which the gas is being contained, it will decrease in temp. I think it is Boyles law in chemistry. It is the same theory that your AC works on. Anyways... the slightly less hot gasses then (still hot to the touch, but not as hot as it was) is moving slower. It then gets passed through baffles before being ejected through the end of the supressor. It works exactly like your car muffler works. With a supressor on, you might actually see a small, statistically insignificant, increase in velocity because the bullet is under pressure longer. The crack will be there as the bullet transcends the sonic barrier (with supersonic ammo) at the end of the barrel (no air to crack to speak of in the barrel). With subsonic ammo, you can get quieter than a .22lr. Some larger cans can get supersonic ammo that quiet... well .30 cal rifle ammo at least.

A supressor that slows the bullet will wear out quickly... one that only slows the gasses will last 10 of thousands of rounds longer before wear affects noise reductions.

-edit- I was wrong, it is Charle's Law, not Boyle's Law.

average_shooter
January 2, 2010, 02:18 AM
Perhaps I missed the memo; when did Wikipedia (an online "encyclopedia" anyone can edit) become an acceptable end-all reference? None of my college professors ever let us cite Wikipedia...

What you initially stated was that suppressors slow the speed of a bullet, which they do not. In your response to the questions raised by your first you use "they" to refer to suppressors. Using "they" typically means you are lumping all types and forms into one group that works the same way, this is not true. To back up your claim you use "...reducing the velocity of the bullet" however you leave off the "...sometimes..."

zombienerd
January 2, 2010, 02:18 AM
its simple science, that is all.

Yup.. There may have been one suppressor some time in history that slowed down the rounds, but modern suppressors DO NOT.

Read the ENTIRE ARTICLE. Find one example of a modern suppressor design that lowers the velocity of the bullet.

ONE..

I dare you.

pat86323
January 2, 2010, 02:21 AM
here is the fact, if something is moving faster then the speed of sound which is approx 1700 feet per second at normal temperature (it actually changes quite alot depending on surrounding temperature) it will produce a sonic boom. If anyone has a design of anything that will prevent something faster then sound from making a sonic boom they should immediately send me the design so i can stop working and going to school. Sonic booms are quite loud so in some cases for a suppressed sound it is REQUIRED for the bullet to slow down. Im not here to argue so i wont. If anyone wants me to explain how this works further pm me as im not going to hijack the thread.

Again, its just simple science.

average_shooter
January 2, 2010, 02:24 AM
I think you're making the assumption that suppressors completely quiet and muffle the sound of a shot; they do not. Even suppressed firearms require the use of hearing protection precisely because the bullet is still going faster than the sound barrier and making that "crack." Suppressors do little more than muffle the sound of the expanding gasses exiting the muzzle and have little to nothing to do with the bullet itself.

pat86323
January 2, 2010, 02:39 AM
again take i have no plans on arguing. I never said that Wiki articles were the end all, i simply used it as a little backup since it was the first thing i found. Im not writing a paper for college, if i was i would have done more then 20 seconds of research. I have little to go on other then what i have learned from science classes and what i picked up from a weapons special on the discovery channel. Things that go faster then sound go boom.....period. No internet discussion will ever change my mind on that. Yes the suppressors quiet gasses, however in order to get the sound down any more you have to get the bullet speed down.

panoz77
January 2, 2010, 02:43 AM
You are missing the point, a weapon with a suppressor firing supersonic ammo is quieter than the same weapon firing supersonic ammo without a suppressor due to the suppression of the gases "the boom part". The same weapon with a suppressor firing SUBSONIC ammo can be almost as quiet as an airgun (no boom and no supersonic "crack" to deal with as the ammo is already slower than the speed of sound) and the sound of the action.

REAPER4206969
January 2, 2010, 03:12 AM
however in order to get the sound down any more you have to get the bullet speed down.
Would you like to explain to the class why ammunition companys make subsonic loads?

pat86323
January 2, 2010, 03:39 AM
yes i would.... a subsonic round moves slower then the speed of sound....thus eliminating the sonic boom and reducing sound. Im not stupid and know where you are going with this. I understand that there is still a need for a suppressor to reduce the sound of the expanding gasses escaping. However by forcing the gasses to go out in many directions you have removed energy from behind the bullet. if you dont believe me go outside right now and get your garden hose..... put a spray nozzle on it, then turn the hose on. Examine how much water is coming out how fast. Then go back inside and get a knife.....poke a hole through the hose about a foot back observe that the amount of energy being released through the nozzle is now reduced. Need more proof? Keep poking holes. I understand that this thing functions as a baffle for expanding gas, i get it.....really i do.

scythefwd
January 2, 2010, 03:49 AM
pat, most supressors don't put a hole in the barrel. It uses all of the original barrel, and then adds length (which actually keeps the pressure behind the bullet up for a microscopic amount of time, therefore adding a few fps to speed, not deducting it). Some people do lose velocity when they use a supressor, but that is because they cut the barrel length down so that the rifle's overall length isn't absurd. The gasses still come out the end of the barrel, and they don't escape before the end of the barrel. As long as you are using the full length of the original barrel, adding a can will not slow your shot down on a modern design. I could be wrong, but you are still getting the same amount of gasses out the end of the barrel... unless there is a design that requires you to puncture your barrel without plugging that hole back up in order to use the can. I wouldn't expect much more decrease from that than magna porting a barrel or adding a muzzle brake. These devices attach at the end of the barrel... so you should have the same pressure all the way up to the end of the muzzle as you did before.

scythefwd
January 2, 2010, 03:53 AM
Lets make this simple... anyone have chrono'd data from before and after they added a suppressor to their gun/rifle for the same loadings (commercial or hand)??

scythefwd
January 2, 2010, 03:58 AM
http://opsinc.us/photo.php@photoId=3rdhk21m240mbs.01.jpg.html

Would you mind explaining how the gasses are being vented off "out in many directions" in this can? It appears to just screw on the barrel.

http://opsinc.us/product.php@prodId=3rdhk21m240mbs.html Link to the original product (.30 cal machine gun suppressor in this case)

pat86323
January 2, 2010, 04:05 AM
ok here we go, ill explain this as simply as i can. Unless im mistaken the inside diameter of the suppressor is very close to if not the same as the diameter of the bore. In order to make the bullet move there has to be some form of compression of gas.... stay with me here. If the inside diameter of the suppressor is very close to the same as the bore, and there are a series of baffles that release gas the compression is greatly reduced. The gasses act very much like water here. Why would they waste energy pushing on that bullet when they can just freely exit through these baffle holes? Therefor by rational reasoning the amount of gas behind the bullet is reduced reducing the amount of energy behind it. Less potential energy behind the bullet equals less kinetic energy passed to the projectile. Now if anyone else wants to argue with me do it with private messages or start a new thread.

scythefwd
January 2, 2010, 04:17 AM
But that doesn't occur until after the bullet has left the barrel and entered the suppressor. If the barrel wasn't cut down to install the suppressor, then there will be no reduction in velocity as the end of the muzzle. Unless the suppressor instantly (as in zero delay... not just very quickly) returns pressures to atmospheric norms, then acceleration will continue to happen until pressure is equalized behind and in front of the bullet. Since that isn't instantaneous, even in a suppressor, then acceleration continues for a practically immeasurable time frame. Unless the suppressor creates a vacuum in behind the bullet or creates a pressure bias in front of the bullet, then no slowdown can occur. The can doesn't just vent out the sides... it still pushes the air out the front, so there must be pressure behind the bullet (above atmospheric norms) until it exits the suppressor. There is a drop in pressure behind the bullet from the gases expanding but it isn't enough to create a vacuum or return to normalized levels or close enough to that to actually effect a slowing of the projectile.

Your hose analogy is flawed. It is more like putting a slightly oversized extension on the hose that still has the same size opening on the other end. Yes, the water takes a little longer to get there, but the mud clod that was blocking your hose is still going to be propelled out of the hose at an accelerated pace. The extension isn't going to slow it noticeably. Also, water doesn't act like super high pressure gasses, so a direct comparison is flawed at its roots.

REAPER4206969
January 2, 2010, 04:30 AM
I'm facepalming here.

pat86323
January 2, 2010, 04:32 AM
alright......ive said many times that i do not want to hijack this thread. this will be my last post in it. when the bullet enters the suppressor (remember this is complete speculation becuase i dont have one here to measure) the diameter is the same or very very close. meaning that the bullet is likely making contact with the bore of it. This creates resistance on the projectile. when the gasses begin escaping through the suppressor the amount of energy is greatly reduced (the gas takes the path of least resistance.) provided that the bullet is in fact making contact with the bore of the suppressor this will reduce its speed very very quickly. If myself and my engineering major roomate are not completely off base here this also explains why they say suppressed firearms have a shorter effective range. The bullet moves slower thus making it lose energy faster downrange. The energy lost through a bullet is exponential. Meaning that it falls more between 100-200 yards then it did between 0-100 yards. The slower it is going the more gravity moves it in said distance. This would be one heck of an explanation as to why a supporessor makes a firearm less effective at range. This seems pretty simple to me, im starting to think that people are arguing just to argue. If anyone else has anything to say my pm box is empty and we wont be cluttering up the forum anymore.


facepalm away friend. Im pretty sure that physics effect lead and steel and gas as it relates to guns as it does to other things. Guns and their accessories still have to conform to the rules set out by the universe.

scythefwd
January 2, 2010, 04:38 AM
pat, your not hijacking. He asked how suppressors worked... this "argument" is wholly on topic..... quite probably the most on topic argument I have seen on THR.

The centerline "bore" of a suppressor is oversized. It might be a .312 for a .308 caliber bullet, probably larger even still, but it is not bore sized. The bullet is not touching it going through. You would completely destabilize the bullet unless you matched the rifling twist exactly. You would destroy any chance of accuracy when the bullet, which is already engraved with the grooves from the rifling of your barrel, slams into the new and not matching rifling of the suppressor... if you didn't do serious damage to the suppressor and yourself. I have seen exactly 1 ballistics changer that screwed into the barrel that had mismatched rifling grooves, but that was on a very low pressure round, destroys accuracy, and is only used on lead rounds (.22lr). You would slow the bullet's rotation way down if they were smoothbore and contact was made. I would expect patterns at 100y and not groups from a silenced weapon if these were the case... making the firearm all but useless. The first suppressors may have been contact based... but anything made recently doesn't actually touch the bullet. Suppressors now don't really affect the accuracy enough to worry about unless you are a benchrest shooter.

pat86323
January 2, 2010, 04:47 AM
if you expect the accuracy to go down at range and are suggesting that the speed to stay relatively the same explain to me why the accuracy would go down if the bullet was not behaving differently? You seem to acknowlage that the bullet would perform less effectively at range......if it is going the same speed and acts the same through a suppressor then the accuracy would not be affected.

scythefwd
January 2, 2010, 04:56 AM
No Pat, I am saying that IF supressors worked by applying drag on the bullet using any method, then I would expect accuracy to be crap. What is true now is that suppressors do not appreciably affect accuracy except to those people who measure shooting accuracy in the millimeters and for money. What is true now, is that suppressors have been designed to get rid of all noise but the sonic crack that are just as accurate as the original gun and are actually capable of adding 50 fps or so to a projectile.

The performance of a round is basically untouched because the suppressors don't touch the round at all. They just act like a muffler. It is going the same speed or very slightly quicker (due to inconsistancies in ammo manufacture... it is within accepted variations in speed), and is just as accurate. I'm not expecting accuracy to degrade at all.

I did not type my last point well, so I will correct it here:

"You would completely destabilize the bullet unless you matched the rifling twist exactly if the suppressor applied drag to the bullet. You would destroy any chance of accuracy when the bullet, which is already engraved with the grooves from the rifling of your barrel, slams into the new and not matching rifling of the suppressor... if you didn't do serious damage to the suppressor and yourself."

pat86323
January 2, 2010, 05:05 AM
if the accuracy is not adversely affected by the silencer, and the performance of the round increases explain to me why they arent used on most police department and military rifles? It would seem to me that at the price that they go for it would be too much of a benefit to not use.....no sound.....slightly INCREASED bullet performance, the same accuracy. Are you telling me that there is somethiong out there that has tons of benefit with no drawback and it isnt being used all the time?

pat86323
January 2, 2010, 05:09 AM
and furthermore the bullet would almost have to make contact on the bore of the suppressor otherwise the gas would just escape out the bore of the suppressor and be just as loud as before. Gasses and liquids will always take the path of less reisistance.

scythefwd
January 2, 2010, 05:17 AM
There are drawbacks. OAL of the rifle, added weight, cost (800+ for some good ones), then need to modify the rifle it goes on to. Most effective rifle suppressors are 6.5-10 inches in length. Many users cut the rifle down to make this less cumbersome, but a military or police unit wouldn't want to do that. They want the bullet to hit as hard as they can get it to and cutting the barrel down by 6 inches will do more harm to bullet performance than the suppressor can make up. Add to that the several hundred dollar cost of each one and it gets very expensive very quickly. Police units aren't usually rich, so they choose to outfit everybody with what they can afford. The political backlash from the addition of suppressors on the cops rifles would be HUGE. Most of the time, approval for gear has to go through a politician, so that usually kills it.

Military....that extra 6 inches hanging off your rifle makes it unwieldy when working close quarters. You need to most maneuverable rifle you can get when clearing a house. You are issued ear plugs, but in reality soldiers don't use them in the field because they can't hear orders as well (or someone approaching their fighting position). Adding close to a pound to the end of my rifle is not what I want when my basic load, plus battle rattle, plus ruck already is running 100lbs of extra weight I am lugging around. Kevlar helmets soldiers are issued weigh 10 lbs. Average ruck is in the neighborhood of 50-75 lbs. Weapon is 9 lbs. Flack jacket is 20 lbs, more if you have a IBA with sappy plates. 210 rounds = another few lbs. Food for the day, plus water and weight becomes a major consideration. Some long range sniper rifles for both the cops and the military supposedly use them.. but I have yet to see it.

EDIT - was wrong on the weight of the Kevlar helmet. It is only about 4 lbs. If you are issued night vision goggles, then you are up 5.5 lbs.

scythefwd
January 2, 2010, 05:20 AM
path of least resistance .... There is more resistance trying to squeeze through a .003 gap than there is going through the baffles, which could be a full .3 inch outlet off the bore. There isn't any extra pressure in the extra volume of the can, so as the bullet passes an outlet into the baffles, gasses are pushed up into them to equalize the pressure, which absorbs more of the gasses than what leaks around a bullet. The bullet is moving 2000 fps, so it is only in the suppressor for about 1/2000 of a second. Gas does escape around the bullet and directly behind it. The suppressor just bleeds some off through the baffles. Some cans are 2/3x the volume of the bore in total, so it really does bleed off a lot of that gas into the can.

REAPER4206969
January 2, 2010, 05:29 AM
This is what happens when a bullet touches a suppressor.
http://www.youtube.com/watch?v=GQ-KG1odvLs

scythefwd
January 2, 2010, 05:39 AM
fun video http://www.youtube.com/watch?v=vhwWS5sU1tU&feature=related

quick and dirty "how a silencer works" with a demo using both supersonic and subsonic rounds

ultradoc
January 2, 2010, 06:39 AM
If you use sub sonic ammo will that be quiter even without a supressor?

scythefwd
January 2, 2010, 07:01 AM
ultra, yes. On my .22lr's it sounded like a loud rush of air instead of the "crack" that most ammo has. It won't compare with a silenced weapon, but there is a difference.

herohog
January 2, 2010, 07:20 AM
pat86323 (http://www.thehighroad.org/member.php?u=29497), let me make this real simple for you:

Suppressors are not DESIGNED to slow down the projectile.
The difference of the speed of a projectile when fired from a rifle with the suppressor removed is statistically no different from the speed of the same projectile through the same barrel on the same gun with the suppressor installed. In fact, as the suppressor ADDS to the effective barrel length, I would argue that it would tend to INCREASE the velocity if anything as those gasses are still expanding and pushing on and around that projectile. With the gasses always being faster than the projectile, they would not induce drag but instead provide thrust beyond the original barrel length without the suppressor!
Suppressors are designed to be used with subsonic ammo so there is no sonic boom to contend with.
Suppressors require maintenance (cleaning) and are expensive and delicate. That is why you don't find them on all/most military guns. Also, because they require subsonic ammo, the effective range is reduced. These are VERY good reasons you don't see/use them everywhere.
Some target shooters actually find they have increased accuracy when using a suppressed gun but there is debate as to weather this is due to the change in barrel harmonics or the suppressor itself.
I am willing to bet that you have never actually fired or personally heard a suppressed gun fire up close if at all.
and furthermore the bullet would almost have to make contact on the bore of the suppressor otherwise the gas would just escape out the bore of the suppressor and be just as loud as before. Gasses and liquids will always take the path of less resistance.
A gap of a few thousandths to 10 or 15 thousandths of an inch itself acts as a baffle. The passages in the suppressor are much greater than that and that is where the vast majority of the gasses and noise go. A perfect seal is not only not needed, it is detrimental to the firearms performance.

You started out saying a suppressor slowed down the projectile to keep the sound down. When that was soundly refuted you kept changing your position clinging to "a suppressor slows down the bullet some". Please just accept that this, if it occurs at all, is insignificantly minimal to non-existent and just let it go.

zombienerd
January 2, 2010, 07:47 AM
I'm facepalming here.

Me too...

I really want to resort to name-calling, it would make me feel better :)

There are lots of words to describe it...

You just can't fix hardheadedness.

Silvanus
January 2, 2010, 08:31 AM
I'm not sure about this but I THINK the H&K MP5 SD does slow down the bullet a little. That way you can use regular ammo and still keep the sound down. A guy who owned one told me this (which doesn't mean it's true at all, he didn't seem very knowledgeable about guns in general), but wikipedia seems to agree ;)

"The suppressor itself is divided into two stages; the initial segment surrounding the ported barrel serves as an expansion chamber for the propellant gases, reducing gas pressure to slow down the acceleration of the projectile. The second, decompression stage occupies the remaining length of the suppressor tube and contains a stamped metal helix separator with several compartments which increase the gas volume and decrease its temperature, deflecting the gases as they exit the muzzle, so muffling the exit report. The bullet leaves the muzzle at subsonic velocity, so it does not generate a sonic shock wave in flight. As a result of reducing the barrel’s length and venting propellant gases into the suppressor, the bullet’s muzzle velocity was lowered anywhere from 16% to 26% (depending on the ammunition used) while maintaining the weapon’s automation and reliability. The weapon was designed to be used with standard supersonic ammunition with the suppressor on at all times.

It may be possible that other sound suppressors work the same. But the majority I know off don't slow velocity down...

herohog
January 2, 2010, 08:46 AM
A suppressor as described above would have to be unusually long and REPLACE a significant portion of the barrel to achieve this. Your standard screw on canister suppressor simply will not do that.

Silvanus
January 2, 2010, 08:49 AM
herohog,

About the part I quoted, is that wrong? This is not a sarcastic question :) I don't know much about physics and my English is far from perfect... I'm genuinely interested to know if that particular weapon system does slow the bullet down or not.

herohog
January 2, 2010, 08:53 AM
See my post above yours. If anything, this would be the exception to the rule.

scythefwd
January 2, 2010, 09:03 AM
As a result of reducing the barrel’s length That is what reduces the bullets speed, not the suppressor. MP5... thats a .9mm?

Or are you attempting to claim that it is possible that decompression chambers alone (what both chamers you described in the quote are) create enough air pressure (has to be higher than atmospheric pressure you are shooting in to decelerate the bullet) in front of the bullet to slow it down close to 100 fps in 10 inches, or it somehow creates a vacuum behind the bullet to do the same thing?? Sound barrier is about 1100 fps at sea level, a gold dot 9mm+p is moving out at 1220. According to speers website, it is still moving approximately 1000 fps at 50y. So, with a standard deceleration of 200fps/150ft or 1.333333 fps per foot, that 100 fps in 10 inches (a long suppressor) drop is looking like there needs to be either a vacuum behind the bullet, physical resistance applied to the bullet, or positive pressure (relative to what is behind the bullet) to actively slow the bullet down if it is the actual suppressor doing it. I am not seeing this as a probability. It is far more likely that the bullet is slowed due to having the pressure from the hot gasses created from the burning powder work on the projectile for a shorter period of time due to a shortened barrel.

But hey, what do I know.... I never attended college.

-edit- it is probably closer to 100 fps deceleration in 7-8 inches. Assuming that the suppressor is 10 inches, we are talking deceleration of the bullet at 10 feet per inches instead of .011 (ish) feet per inches. That means the bullet would be decelerating at a little less than 100 times as fast using the suppressor (again assuming the suppressor is the reason for deceleration).

Boris Barowski
January 2, 2010, 09:19 AM
Pat86323,

In the absence of force, a body either is at rest or moves in a straight line with constant speed.

If a suppressor could suddenly remove all pressure [Edit=equalize the pressure with atmospheric pressure] behind a bullet (=force), that bullet wouldn't suddenly slow down. It will keep moving at a constant speed.

Silvanus,

That suppressor replaces a substantial part of the barrel. This reduces the time gas can act upon the bullet and thus there is less time for acceleration. It seems in the first part they talk about reduced velocity compared to longer barrels while using subsonics. In the last sentence they claim the gun still functions with supersonics, but then you'll still have the sonic boom.

herohog
January 2, 2010, 09:21 AM
As stated in Wiki:
Instead of using subsonic ammunition, one can also lower the muzzle velocity (http://www.thehighroad.org/wiki/Muzzle_velocity) of a supersonic bullet before it leaves the barrel. Some suppressor designs do this by allowing gas to bleed off along the length of the barrel before the projectile exits; others contain wipes that use friction to slow the bullet before exiting. However, wipes generally wear out and lose effectiveness after relatively few shots, and the bleed-off designs require periodic cleaning.
Not that neither of the above apply when you are talking about modern suppressor cans. So, in short, we are both right in that there ARE some suppressors that DO slow the bullet. They are just either old or not what most people think of when you talk about suppressors so I will concede a draw on a technicality... sort of. ;-)

scythefwd
January 2, 2010, 09:24 AM
boris -
We are in agreement, but there is a force (just a nit to pick). If all force is removed behind the bullet, you still have atmospheric presser in front of the bullet.

Boris Barowski
January 2, 2010, 09:28 AM
scythefwd,

true, but for the purpose of trying to explain that a supersonic bullet doesn't get magically slowed down i chose to neglect that :)
When I say remove all pressure behind the bullet, I mean that it the pressure is equalized with the atmospheric pressure. But yes, there will also be drag (=opposite force) by the bullet moving through the air

Owen
January 2, 2010, 10:09 AM
The MP5SD suppressor does have a number of ports in the barrel just in front of the chamber for velocity control. It's unusual and atypical.

I play with suppressed .300 WM and .338 rifles on a fairly regular basis. A typical .300 WM meters around 165 dB unsuppressed, and around 141 dB suppressed. That is with a muzzle velocity of 2950 with a 190gr bullet.

Now, if I can find it, there is a chart that shows that the crack from a supersonic .30 cal bullet is in the 140 decibel range (sound metering for impulse noise is complicated, and very condition dependent) ah here it is...about 1/3 of the way down the page. http://guns.connect.fi/gow/highpow.html Actually, that whole article is pretty good.

The sound from the report is caused by the velocity of the propellant gasses venting. The velocity is dependent on the pressure the gas is at. A suppressor provides a volume for the gas to expand into, and cool down, therefore reducing pressure and velocity of the gasses coming out of the muzzle.

anyway pat, you are a little bit right, but mostly wrong.

scythefwd
January 2, 2010, 10:10 AM
So they are using porting on the barrel instead of the suppressor to manage velocity?

herohog
January 2, 2010, 10:15 AM
Exactly!

Ditchtiger
January 2, 2010, 10:46 AM
Here's one for everyone following this topic.
What are the reasons for using supersonic bullet out of a suppressed weapon?
I'll post my answer later.
Let's see what turns up.

scythefwd
January 2, 2010, 10:49 AM
The advantage is range and trajectory. You use the suppressor to protect your ears.

The sonic boom from the bullet breaking the sound barrier isn't easy to place, and is only heard from very short distances away. Frequently people will guess the wrong direction entirely when hearing a suppressed weapon being fired with supersonic rounds.

There is an energy advantage to using supersonic rounds, and besides... they'll hear the action working anyways :)

Jorg Nysgerrig
January 2, 2010, 10:52 AM
This thread has some good discussion, I'd hate to have to lock it because some folks can't play nice.

WNTFW
January 2, 2010, 11:08 AM
One thing that the local suppressor crowd has told me:
Youtube videos don't do suppressor justice as far as the sound. It has to do with the microphone & sound recording on cheaper video.

Part of the local suppressor crowd included a suppressor mfgr. Another in the crowd was a professional video/photo guy.

My best explanation of how a suppressor works is you trade the intensity of the escaping gas for duration. You spread the gas out over more area for more time.

Personally I have no use for a suppressor. I find them interesting and like to learn about them. I just don't shoot in any venue that would allow using one. Maybe I just have not reached the point where the $$$ is available for such an item.

Ditchtiger
January 2, 2010, 11:17 AM
scythefwd, you got it faster than I thought anyone would.

scythefwd
January 2, 2010, 11:19 AM
ditchtiger - which answer? Guessing on what I was able to read last night about not sourcing the boom. I knew they aren't audible from very far away when they are small objects.

Others are simple physics and common sense.

scythefwd
January 2, 2010, 11:54 AM
pat, what type of engineers are you and your room mate? Mechanical, structural, aeronautic, social, electrical? Just curious.

pat86323
January 2, 2010, 12:23 PM
there were three of is last night discussing this and one was civil (though this really has little bearing on the physics classes and such that you are required) our friend is a mechanical engineer (done with school alltogether) and i am a construction management major which though is not engineering i still have to take alot of classes and such that deal with the environments forces on an object.

And to all of you out there that want to "resort to name calling" if you cant handle a debate fueled by science, and opinion just dont read it anymore. Fact of the matter is there is merit to both sides of the argument, the projectile doesnt slow as much as i previously thought, but it does whether caused by the barrel being shortened reducing the amount of time the environment has to impact the projectile, or by loss of energy due to lost pressure behind it there is no doubt that this has an impact. I reach out to you to please private message me if you want to get in a name calling contest. Scythe and i have had some pretty intelligent dialog if you would like to "stupid up the conversation" go for it just do it elsewhere. Thank you.

Ranb
January 2, 2010, 12:45 PM
IF your looking for advice on how to build one, my advice is don't, it's just a hair illegal without the stamp

Panoz77,

It is a pity that anyone would come to any gun forum and try to talk someone out of making or owning any legal firearm. While you might not be actively discouraging firearm ownership, you certainly are not encouraging it at all in your first post on this thread. While silencer ownership is routine in the USA, the penalties are very severe in comparison to other victimless crimes when ATF authorization is not obtained or the tax is evaded.

The legal requirements for owning a silencer at the federal level are simple and easy to accomplish. It is easier than getting a first time driver’s license or a marriage license. Anyone who can own a firearm can own a silencer. There are no federal laws making silencer illegal to own, there are just a few laws to contend with. All it takes is to be 18 years old (21 to get from a dealer), fill out the ATF form 4 (form 1 to make), form 5330.20, fingerprint cards, photos and a check for $200. The biggest hurdle for some is obtaining the local sheriff’s signature on the ATF form 4. A trust or corp. can be used to own the silencer then the sig, prints and photos are not required. It is a very easy and routine process for those who live in one of the 37 states that allow unlicensed civilians to own them.

Ranb

average_shooter
January 2, 2010, 12:59 PM
...but it does whether caused by the barrel being shortened reducing the amount of time the environment has to impact the projectile, or by loss of energy due to lost pressure behind it there is no doubt that this has an impact.

Adding a suppressor doesn't shorten the barrel. The powder still has the same amount of time to burn whether the suppressor is attached or not. Thus the same amount of pressure will be produced behind the bullet and the same velocities will be reached.

When a bullet leaves the muzzle all of the expanding gasses are free to go out in all directions, thus there is no more pressure behind the bullet pushing it forward. By attaching a tube onto the end of the barrel you don't really cause less pressure to be produced than already would be if there were no suppressor. The tube (suppressor) simply slows and redirects the expanding gasses exiting the muzzle.

Perhaps because of the engineering classes you're overthinking things. I've been guilty of doing the same myself. Often, though, the simple answer is the best.

pat86323
January 2, 2010, 01:07 PM
yeah average but it was stated earlier that many people who use suppressors often shorten the barrel. Im still thinking that something with the suppressor would have to effect the flight of the bullet. We pulled out quite a few physics books and such last night and our engineer friend actually did the math on a couple models (this is waaay past me and i have no idea how it works) and she could explain to us that through the math that she did the forces of the gases escaping around the bullet and through the baffles would effect the stability of the projectile. I am pretty much past the argument and am now more on the mission to run through all the variables that a suppressor can cause and see what it can to do a bullet.

Ranb
January 2, 2010, 01:07 PM
I design and make silencers as a hobby. I have little education past high school, but I have a very good idea of what works and what does not. I have designed and built nine silencers so far, for 22lr to .338 magnum and .510 caliber. All of them work well.

Gun silencers in their simplest form are merely enclosed tubes attached to the barrel muzzle. The gun powder gases enter the tube to expand and cool before being released to the outside atmosphere. It is that simple, cool and expand, just like a car muffler.

The goal for most who design silencers is to make the silencer reduce noise as much as possible. Durability, compact size, and minimizing the affect on accuracy and point of aim are other major considerations. This is where the internals design plays a major role. A good silencer will reduce noise intensity by 20 to 30 decibels. Since decibels are a logarithmic function of sound pressure, 20-30 decibels is a 100 to 1000 times factor change in noise intensity. This is equal to a four to eight times reduction in loudness. Frequency, noise duration and shooting environment all contribute to how differently a person hears the noise of a suppressed firearm. Ultimately the usual goal of the silencer designer is to allow the safe shooting of the weapon without hearing protection. Sometimes they are marginally or not nearly successful.

There are a few designs that work very well at reducing noise, but degrade accuracy and/or velocity. A silencer that uses wipes is one of these. Imagine a 9mm pistol with a threaded barrel that has a tube of 1.25" by 7" attached to it. On the inside are rubber disks with X shaped slots cut in them. The disks are held about an inch apart by spacers that tightly grip the outside edges of the wipes. A wipe suppressor is typically very good at suppressing the noise, but only for a short time. Since the bullet contact the wipes, they damage the wipe with each shot and accuracy is degraded. After several dozen rounds, large holes are blown into the wipes and they reduce noise by much less than when new. I have only seen these types of silencers for 9mm and less powerful cartridges. Wipes are the only silencer part the ATF allows an unlicensed owner to replace without paying another $200 tax.

Another type of silencer that reduces bullet velocity is that which uses a ported barrel as part of the silencer. Many integral silencers that are built as part of the barrel use ports. These silencers can be very effective at reducing noise, but some of them such the 22lr ones can reduce velocity too much. I converted a Lee Enfield rifle to a near Delisle carbine configuration. I removed the spacers and stacked the baffles at the end. I ported the barrel and profiled it to fit the silencer internals. 230 grain ammo that shot 850 fps in a five inch 1911 moved about 1150 fps in the unported Enfield barrel and 1040 fps after the barrel was ported.

http://i171.photobucket.com/albums/u320/ranb40/suppressors/510W-1.jpg

the top drawing shows the silencer set up for a 510 whisper, the middle drawing for the 45 ACP Enfield. Porting the barrel can be a very effective method of further reducing the noise on some suppressed guns.

Ranb

Ranb
January 2, 2010, 01:19 PM
she could explain to us that through the math that she did the forces of the gases escaping around the bullet and through the baffles would effect the stability of the projectile. I am pretty much past the argument and am now more on the mission to run through all the variables that a suppressor can cause and see what it can to do a bullet.

Your friend is correct. Changing anything about the barrel will affect the bullet flight path. The barrel whips around when the gun powder burns; short and stiff barrel whip less. If the barrel crown is perfect, the gases will be released exactly even around the base of the bullet as it exits the barrel thus minimizing the disruption of the bullet flight path.

Attaching a weight (silencer, brake, flash suppressor) to the end of the barrel always changes the flight path, even if it is too small to measure. Attaching a silencer that extends over the barrel can help improve accuracy in a small way. If the silencer screws on at the muzzle and puts tension on a shoulder inches in back of the muzzle threads, then this tension can improve (allegedly) accuracy.

One thing a silencer can do to degrade accuracy is baffle strikes. If the bullet touches the baffle while it passes through, then it will yaw and at the very best will impact farther but consistently from the center. It usually makes the bullet yaw and tumble resulting in a total miss unless you are shooting at close range. the worst case scenario is that the bullet completely wrecks the silencer, pieces break off and go downrange and the barrel is ruined. This has yet to happen to me although I have had minor baffle strikes that made the bullet impact 6 feet low at 100 yards.

As for changing bullet velocity, a silencer equipped with baffles that do not touch the bullet can exhibit something called suppressor boost. As the gunpowder gases are contained in the silencer body for a brief fraction of a second, they can still continue to push on the bullet a small amount. Some people have reported seeing 10-40 fps increases in speed when measuring on a chronograph (I have also), but this increase in speed is significant only in that it shows the bullet is not slowing down inside of the silencer.

A silencer can degrade accuracy (according to some experts) by disrupting gas flow across the bullet's path when using asymmetrical baffles, especially an asymmetrical blast (first) baffle. This is something I have not been able to observe myself. Since I think accuracy is more import than suppression, my blast baffles are always symmetrical.

Ranb

Ranb
January 2, 2010, 01:37 PM
Another kind of silencer is one that merely attaches to the muzzle. No barrel porting, no wipes, just metal baffles and spacers in a tube. The most common baffles types are those shaped like a K, or an M, or a cone, or simply flat washers separated by spacers.

http://i171.photobucket.com/albums/u320/ranb40/suppressors/stepconebafflesilencer4.jpg
Here is a 22 caliber silencer for an AR-15 with 60 degree stepped cone baffles. Most cone baffles are separated by spacers.

http://i171.photobucket.com/albums/u320/ranb40/suppressors/223REMINGTON-2.jpg
Another with K baffles. The K baffles are self aligning and do not require spacers. The muzzle brake mounts to the silencer at two places for good alignment. The muzzle brake is a tight fit along the exterior to help ensure it is aligned to the bore. The silencer bore is between .250" to .300" to aid in suppression. The tighter the bore makes for better suppression but could more likely result in baffle strikes.

http://i171.photobucket.com/albums/u320/ranb40/suppressors/9mmsuppressor-1.jpg

What I made for my 9mm Browning. I shoot cast 147 subsonic in it which really leaves lots of gunk behind. Threaded end caps allows me to clean it out after a few hundred rounds.

http://i171.photobucket.com/albums/u320/ranb40/suppressors/AKsilencer-1.jpg

Compare this to a silencer that extends over the barrel. I was not able to make threads that were aligned well enough to the bore to ensure properly silencer alignment, so I moved the front sight back to allow a two point mount.

Ranb

Ranb
January 2, 2010, 01:48 PM
http://i171.photobucket.com/albums/u320/ranb40/firearms/collection.jpg

Part of my collection. Many more hosts then silencers, so I make them to fit several firearms in most cases.

Ranb

pat86323
January 2, 2010, 02:48 PM
thank you ranb. I couldnt find any sets of prints or plans to look at. I see that i was a little misinformed about how these things were made. My friend now is really fired up and swears that she is going to get her hands on some plans and do all the math to show what will happen to a bullet when fired through each of these suppressor types and to what degree it will happen based on a 308 bullet.

Boris Barowski
January 2, 2010, 03:16 PM
If anyone has solidworks (or similar) simulation files, i'd be very interested :)

Ranb, you mentioned baffle-strikes when using too narrow or off-center baffles. What are the possible consequences of this happening? I imagine a ruined or very unstable bullet, but what will it do to the suppressor and the functioning of the gun during follow-up shots?

Ranb
January 2, 2010, 03:34 PM
My friend now is really fired up and swears that she is going to get her hands on some plans and do all the math to show what will happen to a bullet when fired through each of these suppressor types and to what degree it will happen based on a 308 bullet.

That sounds good. If there is one thing missing from silencer tech it is the science of noise reduction and how to predict how a new design will work. If she has anything of substance, then I hope she posts it on the forum at http://www.silencertalk.com . Her results might generate much disscussion over there.

Ranb

Ranb
January 2, 2010, 03:40 PM
The results of my MINOR baffles strikes have been dented baffles and end caps. This resulted in completely missing the target. I was able to repair the end caps with a hammer. My 9mm and 22lr silencers unscrewed a bit while firing and drooped which is why I got the baffle strikes. My 510 whisper can was used with some new cast bullets I was trying without gas checks. This made them yaw 90 degrees within 25 yards. I did not find this out until I was investigating the cause of the baffle strikes.

http://i171.photobucket.com/albums/u320/ranb40/suppressors/bafflestrike.jpg

Above is a photo of a quality silencer that was destroyed by a single baffle strike. If I remember correcctly it was caused by improper mounting. I do not know if the barrel was damaged or not.

Ranb

MrCleanOK
January 2, 2010, 03:53 PM
http://www.youtube.com/watch?v=SLGrznbs3Mw

I can't believe nobody has posted something like this yet. The effects of a suppressor on standard and subsonic ammunition, all in one video. It's not mine, I just did a search on youtube for "rifle suppressor".

Owen
January 2, 2010, 03:53 PM
the holes in the baffles need to be larger than the bullet to avoid baffle strikes. the longer the bullet, the bigger the holes need to be, because of yaw. it can take nearly 50 yards for the bullet to fully stabilize. M855 has been measured at almost 9 degrees yaw in some cases...

Ranb
January 2, 2010, 04:09 PM
NEGATIVE, on the bullet slow down "theory". To fully realize the potential sound reduction a suppressor is capable of you need to use SUBSONIC ammo, subsonic ammo is slower than the speed of sound to begin with, supersonic ammo is not slowed down below subsonic speed by a suppressor. A suppressor uses internal baffles to reduce sound. [and little rubber tires to slow down the bullet, the kind they use on roller coasters to slow it down at the end of the ride, only really tiny ones]

Since a silencer only works on the gunpowder gases to reduce noise and does nothing for action noise and bullet flight noise, it does not matter what speed the bullet is going when talking about silencer performance.

A silencer may work differently depending on how much pressure it is dealing with. There are theories on what kind of baffles work best with high pressure rifle rounds as opposed to lower pressure pistol rounds. I lack the experience to know which ones are best though.

The whip like sound of a supersonic bullet does not sound loud at all compared to the muzzle blast at the shooter's position, unless the gun is shot under weather protection or indoors where the shock wave can bounce back to the shooter's ear. I have been told that the sonic wave passing by a person down range is rather loud though.

Subsonic bullets can make a humming noise as they move through the air. I heard this while shooting a suppressed 45 acp Enfield at 1000 fps. I thought it might be transonic noise. I lowered the speed to 900 fps and got the same noise so I returned to using the hotter load.

It has been my experience that the most important factor in perceived loudness is the powder charge. Increasing the powder charge increases pressure and gas volume. Al Paulson's book, Silencer History and Performance claims that a 300 winchester magnum and a 308 winchester with identical silencers will show the same reading on a meter due to being the same bore width and similar operating pressure. But the magnum will sound louder due to the longer noise duration caused by the higher powder charge. The only experience I can contribute to this phenomenon is different loads in my suppressed 1895 Nagant revolver. The 700 fps target load using 1.8 grains of powder is significantly less noisy than the hotter load using 3.0 grains moving 1000 fps. I can also say that my 22k-hornet appears much less noisy than my 5.56. I do not have the proper noise meters to measure with though. They are very expensive ($3500 ish) and not the kind you get at the mall.

Ranb

Ranb
January 2, 2010, 04:18 PM
http://www.youtube.com/watch?v=SLGrznbs3Mw

I can't believe nobody has posted something like this yet.

That video seems to be unique in that it shows a big difference between suppressed and unsuppressed fire. It has been my experience that a cheap camcorder and TV or computer speakers do a very poor job of reproducing the difference in noise levels. Here is a link to my suppressed AR-15 using standard and subsonic ammo as well as my Savage 308 with and without a silencer.

http://s171.photobucket.com/albums/u320/ranb40/suppressors/?action=view&current=silencertests.flv

I have subtitles that show what is being shot. You really need to be present to appreciate the big difference in noise levels.

Ranb

Jim Watson
January 2, 2010, 04:19 PM
I don't own a silencer (supressor for the Modern Internet Technologist) but have seen some in action. There are a couple of shooters in the area Long Range club who use supressed .308s for F-T/R competition. Or did before the NRA disallowed them. I have observed the following:

1. There is no detectable degradation in accuracy or trajectory at 1000 yards. Their scores were fully competitive.

2. You still need ear protection. These were small units - I don't know the brand - and while they took a lot off the muzzle blast, were still unpleasant to the unplugged ear. The interesting part was that when I DID listen to a shot with bare ears, I could hear a brief but distinct whistle after the shot as the tube and barrel depressurized from the trapped gas. They were more pleasant to shoot next to with my ears plugged against my rifle.

3. The energy has to go somewhere. These guys have insulated wraps for their supressors so they can handle and case the gun without burns.

4. The shot, as heard from the target pits, is very muffled but the Crack! of the supersonic bullets going overhead through the targets is no different to any other. In military use, you would have no doubt you were under fire but your ability to locate the shooter would be hampered. And a supressor must be a very effective flash hider, too, delaying and cooling the gas escape.

5. Recoil is reduced. The jump of the gun is less and the shooters say they kick less. This is the basis of the NRA not allowing them, it puts them in the same category as a muzzle brake which is not allowed for F class.

Vern Humphrey
January 2, 2010, 04:23 PM
Sonic booms are quite loud so in some cases for a suppressed sound it is REQUIRED for the bullet to slow down
No, the solution to the sonic "boom" (more properly termed "crack" when dealing with small arms) is to select ammuniton with a muzzle velocity below the speed of sound to begin with. In some cases special low-velocity, heavy bullet cartridges (e.g., the .300 Whisper) have been developed for use with suppressors.

Jim Watson
January 2, 2010, 04:33 PM
An old article in Police Marksman said the H&K MP5SD was a hard gun to shoot at any distance as a carbine because the holes in the barrel bleeding off gas to keep the 115 and 124 grain bullets of standard 9mm subsonic really hurt the trajectory and downrange energy. I think you would be better off with a muzzle "can" and inherently subsonic heavy bullet ammo.

Ranb
January 2, 2010, 04:34 PM
The 300 whisper (with 240 grain bullets) is a really nice round, the 338 whisper (300 grains) is even better in my opinion. Both work well out to 200 yards losing little velocity in the process. The 300 whisper has the added benefit of being able to load supersonic to near 30-30 power when 125 grain bullets are used and is much more accurate than any SKS I have ever used.

While the 510 whisper is a monster in comparison when using 700 to 950 grain bullets at 1050 fps. My 7.5 carbine really needs the added weight and recoil reduction of its silencer. But living in WA means I rarely have the opportunity to use the silencer.

Past 200 yards subsonic ammo drops like a rock, but with a mil-dot scope and a range card, it is easy to engage targets at known distances out to 600 yards. Good jacketed bullets for all three are rather expensive, so I have been experimenting with cast bullets. So far they are less accurate and require much silencer cleaning after use. But I can not argue with the cheapness factor.

Ranb

Ranb
January 2, 2010, 04:40 PM
I think you would be better off with a muzzle "can" and inherently subsonic heavy bullet ammo.

I agree. I ported one of my rifle barrels and will never try it again. The heavy bullets with a fast twist are the way to go as long as the shooter is good at guessing the range and the wind. While I enjoy shooting the supersonic stuff too, I like the subsonics better. :)

Ranb

panoz77
January 2, 2010, 06:44 PM
IF your looking for advice on how to build one, my advice is don't, it's just a hair illegal without the stamp
Panoz77



It is a pity that anyone would come to any gun forum and try to talk someone out of making or owning any legal firearm. While you might not be actively discouraging firearm ownership, you certainly are not encouraging it at all in your first post on this thread. While silencer ownership is routine in the USA, the penalties are very severe in comparison to other victimless crimes when ATF authorization is not obtained or the tax is evaded.

The legal requirements for owning a silencer at the federal level are simple and easy to accomplish. It is easier than getting a first time driver’s license or a marriage license. Anyone who can own a firearm can own a silencer. There are no federal laws making silencer illegal to own, there are just a few laws to contend with. All it takes is to be 18 years old (21 to get from a dealer), fill out the ATF form 4 (form 1 to make), form 5330.20, fingerprint cards, photos and a check for $200. The biggest hurdle for some is obtaining the local sheriff’s signature on the ATF form 4. A trust or corp. can be used to own the silencer then the sig, prints and photos are not required. It is a very easy and routine process for those who live in one of the 37 states that allow unlicensed civilians to own them.

Ranb

Ranb, I did not discourage GUN ownership by suggesting the building from scratch of a suppressor is illegal "without the stamp", thanks for your bias on the matter.


Anyone who can own a firearm can own a silencer.
Ranb

Are you sure about this?? Glad you at least attempt to clarify "of the 37 states that allow them". To suggest anyone who can own a firearm can own a silencer is irresponsible when they are illegal in 13 states as you state much later in your paragraph. But hey they are legal in 2/3 of the US to us common folk.

Ranb
January 2, 2010, 06:54 PM
IF your looking for advice on how to build one, my advice is don't

So how are you encouraging gun ownership by suggesting a person not make a silencer? No bias on my part, just reading your words. Most people who know silencers are legal know about the stamp. Since you know silencers are legal why not encourage making them?

You ever heard of a person who got into legal trouble just for owning a registered silencer? I never have. It is only those who make them without the FFL/SOT or stamp, or possess them after breaking the law who are in trouble.

I was speaking of federal requirements when I said that anyone who could own a gun could own a silencer, so yeah I am very sure. Got a law that says otherwise?

Ranb

panoz77
January 2, 2010, 07:06 PM
I suggest to you that MOST people who ask "how do suppressors work" as in the OP, know nothing about the legal process in owning one or the tax stamp or they wouldn't be asking the question. The OP may have known how to own one legally but not have a clue how they work, but I doubt that is the case (this is not a jibe at the OP).

Ranb
January 2, 2010, 07:12 PM
So how are you encouraging gun ownership by saying "IF your looking for advice on how to build one, my advice is don't...."

You seem to be avoiding a direct answer to my question. Did you think you were encouraging gun ownership when writing your first sentence? Why or why not?

Ranb

panoz77
January 2, 2010, 07:30 PM
No, I am not discouraging firearm ownership, I am addressing the manufacture and ownership of silencers and suggesting nothing about firearm ownership, that is your interpretation of something I didn't say, plain and simple. I also qualified my statement by saying "without the tax stamp", thus implying that there was more than just duct taping a pop bottle to your muzzle and thinking you would be legal.

PT1911
January 2, 2010, 07:42 PM
after checking out several videos... I dont see much point in shooting with a silencer and supersonic ammunition.... kinda defeats the whole purpose.

Ranb
January 2, 2010, 07:54 PM
No, I am not discouraging firearm ownership

Well suggesting a person not build a silencer certainly sounds discouraging. I never said you did anything wrong. It is just a pity you did not instead suggest that they be used to enhance the shooting experience.

Ranb

Ranb
January 2, 2010, 07:56 PM
after checking out several videos... I dont see much point in shooting with a silencer and supersonic ammunition.... kinda defeats the whole purpose.

The diffference in noise between suppressed and unsuppressed is very dramatic when you are actually there listening to it. Most internet videos simply do not do the silencers justice.

Ranb

panoz77
January 2, 2010, 08:04 PM
Again, I am discouraging ILLEGAL activity (illegal manufacture of suppressors), not legal activity or firearm ownership, your attempts to put words in my mouth are trollish.

Boris Barowski
January 2, 2010, 08:12 PM
come on, let's play nice and keep this interesting engineering/science related topic open. If desired you can continue in PM :)

Ranb
January 2, 2010, 08:21 PM
The words I was concerned with were "IF your looking for advice on how to build one, my advice is don't". You wrote them, not me. It hardly matters that you said it was illegal without the tax stamp. Duh!!! Everyone in this thread knows this.

What you should have been saying was to build one, but get the tax stamp first. That is how to encourage gun ownership. Would you tell a person not to drive a car on the highway because "it's just a hair illegal without the" license?

Ranb

panoz77
January 2, 2010, 08:23 PM
Yes, I would

panoz77
January 2, 2010, 08:25 PM
Yes, I would

Again, you have edited my post by abbreviating it, this is the third time you have done it which makes you a troll. I am assuming the OP likely did not know it required a tax stamp, which is whom I was directing my post.


IF your looking for advice on how to build one, my advice is don't, it's just a hair illegal without the stamp
Panoz77

Owen
January 2, 2010, 08:41 PM
can we stop the lame chest beating and get back to the technical, not legal, question the OP asked?

panoz77
January 2, 2010, 09:01 PM
It think the technical aspect has been covered. It's a tube with baffles.

Ranb
January 2, 2010, 09:14 PM
About the bore of a silencer. Unless wipes or mesh are used, it can be catostrophic if the bullet touches the baffles. While wipes and mesh are flexible, made to be punched through, aluminum or steel baffles will make the bullet tumble possibly make it turn sideways then tear the silencer apart from the inside out.

Ideally the barrel is perfectly straight, the bore is centered in the barrel, and the twist is fast enough to keep bullet yaw to a minimum. This would allow the silencer maker to keep bullet/baffle clearance to a minimum as long as he or she is able to mount the silencer perfectly straight to the barrel/bore. In this ideal situation, I would be able to confidently make the bore only ten thousands larger than bullet diameter.

The reality can be much different.

http://i171.photobucket.com/albums/u320/ranb40/firearms/358barrel.jpg

Above is a Savage 358 win barrel I chopped down then turned for mounting a silencer. The bore was seriously off center from the exterior of the barrel. While I would have no problem matching the silencer alignment to the barrel, the bore will not shoot the bullet on a straight path through the silencer. The ony way I can use this barrel and prevent baffle strikes is to make the silencer bore larger to allow more clearance for the bullet; in this case at least .408 inches. This will allow more noise out.

http://i171.photobucket.com/albums/u320/ranb40/firearms/savagemuzzle.jpg

This is an example of a good quality barrel from Pac-Nor. The bore measured within .001 inches from the barrel exterior. I was able to make a silencer with a much tighter clearance. If I could afford it, I would go with quality custom made barrels for all of my suppressed projects.

Ranb

scythefwd
January 2, 2010, 09:36 PM
Pat,
Wasn't trying to go low road. I was just interested in the background of the people I was debating with. A mechanical engineer may look at it from a slowing down the bullet standpoint, where an automotive engineer would possibly look at it from a muffle the gas noises. The others pretty much have very little to do with they physics in there, and social engineering is a type of hacking on computers... these were all thrown in factiously. There are different disciplines that are focused on depending on the type of engineering being done, so it would make sense that while being technically correct... the solution could be approached that way, it could still be wrong for the way the solution is actually applied in real life. I would love to see the models that your friend comes up with. Thanks for keeping it high road and not answering back to the "I wish I could start calling people names" types posts.

scythe

Ranb
January 2, 2010, 09:56 PM
Here is one of the first silencers I made. It is 2 by 18 inches all aluminum with screw on end caps. The design is very primitive, but it works well mainly due to the large size and 60 degree cone shaped baffles. Had I made it this year, I would have used .035" 4130 steel tubing, thin step cone baffles and welded end caps. I would have reduced the length to 16 inches. The improved baffles would reduce noise more and the shorter length and smaller volume would have been offset somewhat by the thinner tubing walls. Making the front end cap in the shape of a baffle would help too. It would look more like the third drawing in post #66.

http://i171.photobucket.com/albums/u320/ranb40/suppressors/photos_510w_2.jpg

Eventually the blast baffle will be eroded by the hot gun powder gases. When it starts to show signs of erosion, I will shift it to the end farthest away from the barrel and let another baffle take the abuse. If it lasts over a thousand rounds, then I will be happy to replace it with something I can make better.

I made this one from scrap bar stock and only had to buy a two foot piece of tubing from Online Metals in Seattle. A very low budget silencer indeed. I envy those in Europe who do not have to put up with the BS tax and red tape to keep gun mufflers legal :)

The above photo shows the parts in a new unfired condition. After a few hundred rounds they look more like these baffles from my 9mm silencer.

http://i171.photobucket.com/albums/u320/ranb40/suppressors/Kbaffles.jpg

Then 9mm K baffles are shown after I spent some time scrubbing off the gunk from cast bullets. I had to use a sharp tool to scrap off some of the gunk then a green scrub pad to finish it. Some day I will not be able to take the silencer apart because there will be too much gunk on the tubing to allow the baffles to slide out. I can only hit them so hard with a mallet and wood dowel to force them out before wrecking them. After that the can will eventually fill up with lead and other debris that can not be flushed/dissolved out and will have to be replaced when performance degrades.

This is why some silencer owners refuse to use cast bullets in their silencers. Since I spent much less on mine, it is not as much of a concern.

Ranb

herohog
January 2, 2010, 10:02 PM
Wow! Talk about MAJOR thread drift at the end! I enjoyed talking to all last night/this morning and was glad to see I was "in the ball park" when the "pros" weighed in. I believe the OP's question has been well answered and the legalities, even though not a part of the OP have been covered as well.

Short summary: If you get a suppressor you will need to pay a $200 tax and meet all the state and local laws. Once you do that you can buy/have your barrel threaded and install the "can" of your choice. For full effectiveness, use heavy sub sonic ammo. The suppressor is nothing more than a muffler for a gun that allows the gasses to expand, cool and the sound to also be reduced by the use of internal baffles. Right? We still all friends? I know I'm happy anyway.

herohog
January 2, 2010, 10:05 PM
Ranb,
Couldn't you solvent or a small cylinder hone to save the tube?

Ranb
January 2, 2010, 10:17 PM
I have considered a hone to try and grind away the gunk. The problem is that the gunk is rather hard and I think I might end up reducing wall thickness in some spots before all of the gunk is gone. I will get agressive before I decide to chop up the silencer and make a new one though.

I heard that vinegar and hydrogen peroxide works, but is tough on aluminum. Sand blasting will work, but I might not be able to get the right angle to attack the gunk when the ID of the tube is only about an inch.

Ranb

Ranb
January 2, 2010, 10:27 PM
Wow! Talk about MAJOR thread drift at the end!

Short summary: If you get a suppressor you will need to pay a $200 tax and meet all the state and local laws. Once you do that you can buy/have your barrel threaded and install the "can" of your choice.

You are right, I should have not allowed myself to get derailed. Sorry to all here.

You might say this is too nitpicky, but it appears that you assume that a person pays the tax then buys some silencer.

The way it works is that you apply for the stamp by filling out the ATF form 4 (have to know the silencer serial number to do this) and send it in with the other forms and the check. Look here; http://test.titleii.com/form4.html for the ATF form 4 (click on the submit button at the bottom of the page). Most dealers want to be paid for the silencer before the ATF form 4 is sent in. The application is just for the one silencer or other title 2 weapon identified by type and serial number.

If you already knew this then cool. :)

Ranb

herohog
January 2, 2010, 10:42 PM
No, I didn't assume that. I figured that anyone wanting one would make darned sure they could qualify for the stamp before doing anything else as it is the only show stopper outside of the money.

Ranb
January 2, 2010, 11:19 PM
The check or money order is normally cashed soon after the application is sent in. It has been taking 2-4 months for approval lately. If the application is denied for any reason, the ATF sends a refund. I have heard they will also refund the tax if the person tells them they did not take possession of or make the title 2 weapon they applied for.

From the reading I have done on various forums, failure to obtain approval is one I have rarely ever heard of. The most common complaint I have read is the local police chiefs refusal to sign the back of the form. The only ATF denials I have ever heard of I think are some from Michigan after the AG there said he interpreted the state law as not allowing them. I think they are still SOL on silencers there too.

Ranb

herohog
January 3, 2010, 12:07 AM
I was speaking more of the legal restrictions in some states/locals and and on the local LEO sign-off. If it's not legal and/or the LEO won't sign off, there is no point in going forward.

Enough drift. I am done.

Boris Barowski
January 3, 2010, 05:03 AM
I envy those in Europe who do not have to put up with the BS tax and red tape to keep gun mufflers legal

In most European countries, suppressors are not allowed. In others they are but only on rimfire rifles. In some they free. I am confident in saying that the US has one of the most free suppressor related laws, but I admit having to pay the tax can be steep :)

But where I live (Belgium), I cannot own a suppressor.

Ranb
January 3, 2010, 07:44 AM
If it's not legal and/or the LEO won't sign off, there is no point in going forward.

If the CLEO will not sign, you can still ask a judge or DA to sign. The most common way around the CLEO signature in states where silencers are legal is to create a trust or corporation to own the silencer for you. These entities are not individuals and the ATF does not require that they submit photos, fingerprints or obtain the sheriff's signature.

I never had a problem getting the sheriff to sign. When a new one was elected, I sent him a nice letter telling him about my hobby and that I was always able to get his predecessor to sign my ATF form 1's. I told him that I could create a trust and avoid his signature but that I wanted to own my silencers personally for now. He sent back my forms signed along with a note thanking me for jumping through the hoops.

Eventually I ended up creating a trust for other reasons. My brother wanted a silencer but lacked the tools to make one and he lives in another state where they are legal. I drew up a revocable living trust using Quicken Willmaker and got it notarized with myself and brother as trustees and my daughter as the beneficiary. As trustees, my brother and I share any property listed in schedule A of the trust, which means I can make a silencer with the trust as the owner and hand it over to him to use.

I did just that and he is very happy with his new silencer. All he did was to fill out the ATF form 1 with the trust as the owner using his address. When it was approved he sent me a copy and I spent 18 hours on the lathe making it, and then sent it to him. Upon the death of the trustees, the beneficiary owns the silencer tax free. My other silencers are in my will and will go to my heirs tax free on an ATF form 5.

Ranb

herohog
January 3, 2010, 01:02 PM
Very good info in this thread! I WILL be saving a copy of it as I wouldn't mind suppressing my .22s for quiet use around the property.

KBintheSLC
January 3, 2010, 03:00 PM
what a suppressor does is slow a bullet down to a speed less then that of the speed of sound. That way no sonic boom created by the bullet. Is that the answer you were looking for?

This is just awesome. I can't wait to get one.:banghead:

navyretired 1
January 5, 2010, 03:03 AM
To be effective the supressor must be used with subsonic ammo, then the hot expanding gases get baffled to divert and cool them slowly relative to bullet. The pressure bleed thru bullet channel or vent holes. Silencing is a relative term and is used by snipers just to confuse the direction and distance fire came from.
I've personnely witness only 2 really effective silencers. The first was a very beat up looking modified S&W mod 39 "hush puppy" which was actually used to hush puppys in enemy ville's by Navy Seals. It was effectively a single shot with a slide lock to prevent slide opening when fired. It sounded like a slight cough. The second was recently a modified Ruger mk 2 with the suppressor which looked like the bull barrel on a target model. Buddy I'm telling you that baby was quite, It was fired into a trash can full of sand during a training lecture and nobody reacted to sound at all and we were told afterwards that 10 rounds of 22 LR subsonic had been fired.
I've got a book that shows that many suppressor designs have been submitted for patent. Most suppressors require constall rebuild as the hot gases burn out buffer material. Buffing materials have included foam discs, open area baffle areas, steel wool, grease and water and many other. Beleave it or not a 2 liter soda bottle makes a pretty effective suppressor .
BTB penalty for unregestered suppressor or peices thereof will get same sentence as machine gun. that means 1 baffle is a suppressor.

Ranb
January 5, 2010, 01:50 PM
To be effective the supressor must be used with subsonic ammo,.....
Most suppressors require constall rebuild as the hot gases burn out buffer material. Buffing materials have included foam discs, open area baffle areas, steel wool, grease and water and many other. Beleave it or not a 2 liter soda bottle makes a pretty effective suppressor.

Wrong on the subsonic ammo claim. Since silencers only work on the muzzle gases, the speed of the bullet is irrelevant. Any silencer that reduces noise by 30 decibels (1000 times less noise intensity) is very effective, even if it is still rather loud. A silencer does not have to make a gun quiet to be effective.

I do not know what history or experience you have with silencers, but if you make them out of aluminum, steel or other durable metals, then they will last thousands of rounds with little maintenance and without a re-build as long as they are not overheated. The only people using ablative materials for silencer guts are those who do not now how to make a good quality silencer or are too cheap to do so. While using water, grease or other substances (shooting wet) to increase silencer effectiveness is common with pistol silencers, most of these silencers are still made from high quality materials that do not wear out quickly.

I think a soda bottle only makes a good silencer if one only cares about noise. If you care about safety and accuracy, then they suck big time. They are bulky, cover the sights and only work well if stuffed with something that blocks the bullet path. I have used one of my silencers with the baffles taken out, it was noisy. The noise was significantly reduced by adding just one baffle. There is just no substitute for a good set of baffles if you want something that is effective and durable.

Ranb

Vern Humphrey
January 5, 2010, 02:02 PM
Wrong on the subsonic ammo claim. Since silencers only work on the muzzle gases, the speed of the bullet is irrelevant.
The point he is making is that a silence does not muffle the sound of the sonic "crack" made by supersonic bullets.

KBintheSLC
January 5, 2010, 02:29 PM
Wrong on the subsonic ammo claim. Since silencers only work on the muzzle gases, the speed of the bullet is irrelevant.

Not true... the bullet speed is in fact very relevant as mentioned above; the supersonic crack will defeat the purpose of even the most effective suppressor. That is why sub-sonic ammo such as the 147g 9mm was developed, to remove that factor. Granted, even supersonic center fire rifles are more quiet when suppressed. However, it is always marginal at best. IMO the quietest guns are suppressed carbine-length weapons that fire sub-sonic pistol rounds.

Sweden
January 5, 2010, 02:46 PM
Pat86323,


If you have access to a fluids professor, they will probably be able to help you get your head wrapped around modern suppressor dynamics. The gas is a fluid afterall.

I am an engineer although mechanics in not my specialty. I own many 'cans' and I shoot at altitudes ranging from ~5,000 ft to over 12,000 ft. The atmospheric conditions induce more volatility than most ammo will. Having said that, I shoot 22lr up to 300Win Mag suppressed. I've had "sub-sonic" loads crack due to altitude. In all conditions and with every load (assuming barrel length remains static) I chrono a slight increase in muzzle velocity with can, usually about 1%.

Ranb
January 5, 2010, 03:06 PM
Let me explain it another way. An automobile makes several different kinds of noise. Engine, transmission, wind, tire and exhaust noise are examples. While there are ways to reduce each type of noise, the muffler only reduces exhaust noise. So I disagree with the claim that to be effective the supressor must be used with subsonic ammo

Now consider the firearm and its muffler. The firearm (even bolt guns) makes action, bullet flight (even subsonic), cylinder gap (most revolvers), and target impact noises. I can not say that a silencer is only effective if it also reduces bullet flight noise. But the weapon system, if it is graded on the noise it makes, is the most effective when used with a long barrel, closed action, light powder charge and subsonic ammo. The silencer effectiveness (when measuring sound levels only) is strictly a function of suppressed and unsuppressed noise levels, nothing else.

In my opinion, a silencer on a 300 whisper carbine that reduces noise from 150 decibels to 120 decibels is more effective than a 22lr silencer that reduces noise from 127 decibels to 117 decibels. Even though the 300 whisper carbine in this case is 3 decibels noisier or twice the intensity of the 22lr, the silencer it is using is reducing noise intensity by 1000 times (8 times less loudness) compared to 100 times (4 time less loudness) for the 22lr.

That said, I very much admire the 22 caliber rim fire rifles and carbines that are outfitted with a good silencer. They are the least noisy of any lethal firearm I have ever seen. I also am fond of those center fire rifles that are made for subsonic ammo like the 458 Socom and Whisper series. The subsonic ammo using heavy bullets and comparatively low powder charges really makes a big difference in the how well the total package reduces noise compared to a 223 Remington or 308 Winchester using standard ammo.

While there is no substitute for subsonic ammo, it is not the one thing that makes or breaks a good suppressed firearm. There are some things that subsonic ammo just can not do. One of them is effective targeting at long unknown distances. If anyone here can do this, then I would like to know how you are getting it done. :) Thanks.

Ranb

chevyforlife21
January 5, 2010, 03:07 PM
the silencer is like a muffler on a car it silences

Ranb
January 5, 2010, 03:12 PM
The atmosphic conditions induce more volitity than most ammo will. Having said that, I shoot 22lr up to 300Win Mag suppressed. I've had "sub-sonic" loads crack due to altitude.

Sweden,

I have read that the speed of sound varies greatly with temperature, but very little with air pressure in the lower atmosphere. Is this true? Thanks.

Ranb

Sweden
January 5, 2010, 04:01 PM
Ran,

I don't want to add confusion to the discussion, I should have referenced Altitude Density instead of altitude. Sound travels slower as density altitude increases. Density is a function of both Pressure and Temperature. Hence why more humid conditions (pressure) or higher temps will reduce density.

The speed of sound is calculated as a function of density. I think you may have 'observed' more variation with temp as that variable is much easier to change drastically then pressure. You've piqued my interest and I'd love to hear from some of the better informed. Z.Smith will prove an excellent resource I'm sure!

Owen
January 5, 2010, 06:48 PM
Not true... the bullet speed is in fact very relevant as mentioned above; the supersonic crack will defeat the purpose of even the most effective suppressor. That is why sub-sonic ammo such as the 147g 9mm was developed, to remove that factor. Granted, even supersonic center fire rifles are more quiet when suppressed. However, it is always marginal at best. IMO the quietest guns are suppressed carbine-length weapons that fire sub-sonic pistol rounds.

I disagree strongly. With a rifle you can get nearly 20 dB of reduction. That is a huge huge difference. A 3dB reduction indicates a halving of the SPL. In addition, the crack actually helps conceal the shooters position, because it sounds like it is coming from anywhere but the shooters position.

Of course, if your purpose ios to make sure no one knows you're shooting, then you can't actually hit anything either...the bullet's impact is quite loud too. Not to mention the screaming people and exploding heads....

Ranb
January 5, 2010, 07:05 PM
For anyone interested in some math, here is how to calculate the change in noise levels given a change in decibels.

Where X = Initial noise level minus final noise level
Change in intensity = 10^(X/10) Given 30 decibels change = 1000 time less intensity.
Change in sound pressure level = 10^(x/20) Given 30 decibels change = 32 times less intensity.
Change in loudness = 10^(X/33.22) Given 30 decibels change = 8 times less loud.

Perceived loudness is subjective. It is influenced by the shooting environment and the individual's ability to hear certain frequencies.

Ranb

Vern Humphrey
January 6, 2010, 03:24 PM
With a rifle you can get nearly 20 dB of reduction. That is a huge huge difference. A 3dB reduction indicates a halving of the SPL.
Depends on where you measure. Near the firing position, yes. In a general down-range location, no, since the "crack" will overpower the "thump."
In addition, the crack actually helps conceal the shooters position, because it sounds like it is coming from anywhere but the shooters position.
That is correct. In the Army we teach the "crack-thump" method of locating the source of fire -- the soldier is trained to be alerted by the "crack" and to listen for the "thump" which reveals the source of the shot. Actual combat experiments in Viet Nam showed when suppressors were used, enemy soldiers were confused and had difficulty in locating the source of our firing.

Wahoo95
January 6, 2010, 03:46 PM
Wow...all I can say is wow the first couple of pages of this thread are SO full of misinformation that it's very difficult to read! Let me clear up a few things:

1) Muzzle Attached silencers do not slow down bullets. It's actually common to see an ever so slight increase in velocity. Integral silencers do cause a loss of velocity by bleeding off pressure/gases via ports in on the barrel thereby reducing velocity keeping the bullet subsonic. Which brings me to another point....

2) Subsonic ammo tends to travel < 1,100fps with the sweet spot being no greater than 1,080fps. I say sweet spot because the speed of sound does fluctuate with altitude and weather conditions. I like to load my 9mm rounds to 950fps which is very quiet sounding more like a nail or paintball gun.

3) Silencers suppress the muzzle blast by controlling the speed at which the hot gases exit the muzzle.

4) Even though you can't suppress the supersonic flight of a bullet, it still has value since supersonic cracks are non-directional meaning you won't be able to get a direction on where the shot came from.

5) Silencers are most effective using ammo that has been loaded to < 1,080fps regardless of caliber.

6) Silencers have been proven to increase accuracy and reduce recoil.....for those who wonder why shoot supersonic ammo through a silencer :)

7) You can build your own silencer if you have the tools and skills for less than $20 as long as you've gotten your approved Form 1($200) in hand first.

8) Silence is golden!!!

http://i210.photobucket.com/albums/bb244/a996hawk/IMG_3752.jpg
http://i210.photobucket.com/albums/bb244/a996hawk/IMG_2573.jpg
http://i210.photobucket.com/albums/bb244/a996hawk/IMG_2688.jpg

smoketheresfire
January 7, 2010, 12:54 AM
the silencer is like a muffler on a car it silences
Wow, thanks for that little gem.

This thread just keeps getting more hilarious. It is clear that there are a good many people who have opinions on silencers who have NOT SHOT A SILENCED WEAPON. If you had you would know that (with a quality suppressor) there is a tremendous reduction sound even when using supersonic ammo. That it does not negatively affect accuracy. And that applying all the physics you want to it will not change the FACTS that wahoo95 just laid out.

inbox485
January 7, 2010, 01:29 AM
I've skimmed through responses and didn't see the short and simple answer.

A silencer uses a series of baffles to convert sound energy into thermal energy.

Riss
January 7, 2010, 01:50 AM
Wahoo got it all right. You all need to go back and read either his post or all 3 books written by Al Paulson on the subject. It is not the baffles converting the sound into thermal energy. It is (partially) the surface area of all of the baffles soaking up the heat and cooling the gasses which helps to reduce the amount of gasses that are released. This and the delay in how fast they are released, and change in the frequency of the sound that they make to a range which is less easily heard by the human ear. Many, many things are factors in how a suppressor works, and many of the things listed prior are simply not involved.

Ranb
January 7, 2010, 01:15 PM
Of Paulson's books on silencers, I have only seen these;

Silencer: History and Performance, Volume 1: Sporting and Tactical Silencers
Silencer History and Performance: Cqb, Assault Rifle, and Sniper Technology
Firearm Suppressor Patents: Volume1: United States Patents (Paperback)

I have not seen a volume 3 for silencer history and performance. Where did you get yours? Thanks.

Ranb

Ranb
January 7, 2010, 01:26 PM
I've skimmed through responses and didn't see the short and simple answer.

Read more, skim less :) My first post on how they work had this near the top; "It is that simple, cool and expand, just like a car muffler."

There is some bad info in this thread, but lots more that is good and useful even if it does not directly pertain to how silencers work.

I recommend that any shooter interested in enhancing their experience try out a good quality silencer sometime if it is legal in their state. Do not let anyone discourage you by saying they are illegal or too difficult to own. It is a routine and easy matter.

Ranb

Riss
January 7, 2010, 01:31 PM
There are 3 books and I think that you just named them all.

Ranb
January 7, 2010, 04:08 PM
Opps, I heard there was a Vol 3 of Silencer History and thought you were referring to that one. Do you have the silencer patents volume? Does it have drawings of modern designs?

When I got the first book, I was dissappointed to find that it was not a "how to" book or a reference on modern designs, but am glad I got them both just the same.

I am always on the lookout for something new to make on my lathe, and it seems that the most usual good sources are those people who make them as a hobby like myself. One of these days I have to get a good meter and post results.

Ranb

Gideon
January 9, 2010, 01:25 PM
Some of the ignorance displayed in this thead is scary. A quick search will give you the answer. To think anyone would think the bullet would ever touch any part of the suppressor :eek:

Car muffler, disruption of sound waves, etc. A suppressor simply baffles the sound waves being produced from.

1. Sound from the mechanical operation of the gun
2. The pop of the primer and burning of the powerder charge
3. and to an extent the sound from breaking the sound barrier

No suppressor suppresses all of the sound, so the quieter the mechanics on a gun and the less of a charge going off (.22 versus .223) and whether you have a sonic boom or not all factor in.

If a bullet hits one of the baffles inside it's called a baffle strike and it's a bad thing that can damage or even ruin a suppressor. there are all kinds of different baffle designs but basically you're trying to capture the sound waves and turn them back on themselves in a confined space until you have some level of dissapation.

Gideon

Riss
January 9, 2010, 01:28 PM
The best how to books are actually not how to books anyhow. If you want to build one then looking through all of the patents and construction diagrams is required, also the theory, physics, and basic how they work books are needed.

Vern Humphrey
January 9, 2010, 01:43 PM
1. Sound from the mechanical operation of the gun
Suppressors do not suppress sound from the mechanical operation of the gun. In fact, many guns suppressed for special operations have locks that prevent the gun from cycling and ejecting the fired case for just that reason.

2. The pop of the primer and burning of the powerder charge
Neither of these are significant -- what is significant is the excape of high pressure gas at the muzzle, and it is this high pressure gas that the suppressor modifies.
3. and to an extent the sound from breaking the sound barrier
Suppressors cannot affect the sonic crack because that occurs all along the bullet's trajectory -- as long as it remains supersonic.

Suppressors suppress only the sound of escaping gas at the muzzle.

Owen
January 9, 2010, 02:29 PM
what Vern said

DaveBeal
January 9, 2010, 03:12 PM
Some of the ignorance displayed in this thead is scary. A quick search will give you the answer. To think anyone would think the bullet would ever touch any part of the suppressor :eek:

From the Wikipedia article on 'suppressor' (http://en.wikipedia.org/wiki/Suppressor):
Wipes are inner dividers intended to touch the bullet as it passes through the suppressor...

cornman
January 9, 2010, 03:16 PM
Is there a way to manufacture a gun that makes it quiter but not necesarilly a silencer? I would think there would be a market for that. I hate shooting anything but a .22 rifle because of the loud noise.

Ranb
January 9, 2010, 07:32 PM
Longer barrel and a lighter powder charge makes for less noise. Think 22CB and a barrel greater than 16 inches.

Ranb

Al Thompson
January 10, 2010, 04:14 PM
Cornman, I would think that something like a 40 inch barrel would help. :) Or you could spring for ear plugs. :D

Confederate
January 10, 2010, 05:10 PM
Everything I know about suppressors I learned from GET SMART. You just screw it on to a revolver and it goes pffft...pffft...pffft so you can hear what 99 is saying to you on the shoe phone.

What could be simpler?

For a suppressor to work, it doesn't necessarily need to reduce the speed of sound. A crrrrkkkk usually doesn't attract the attention a full-fledged Bang! does. Someone might look up and wonder what it is, but they'll usually go back to what they're doing and not give it much more of a thought. If they hear a Bang! without the crack, they also tend to dismiss it...maybe as a backfire.

So suppressing the bang or the crack will yield benefits. If you search on YouTube, you can see how quiet some suppressors are.

Police in some cities fear knives more than guns because they're silent. Gun shots can be detected far more easily by experiened soldiers or LEOs. To get a good bearing you need to hear at least two shots.

Suppressors can be effective in many situations and a good machinest can figure out how to make them. I would think expanding gas would be harder on the eardrums than the sonic boom, but I don't know. I do know that reducing velocity also reduces effectiveness.

Ranb
January 10, 2010, 05:23 PM
a good machinest can figure out how to make them.

You don't even have to be that. I bought a metal lathe several years ago just to make silencers. The only experience I had working metal on a lathe was on the one I bought, and I only fiddled around for a few hours cutting tubing and barstock to get a feel of it. I learned how to operate the lathe while making my first silencer, for a 300 whisper rifle. The silencer works well and I still use it.

http://i171.photobucket.com/albums/u320/ranb40/suppressors/300whisper.jpg
http://i171.photobucket.com/albums/u320/ranb40/firearms/ar-15300whisper.jpg

Ranb

Zak Smith
February 18, 2010, 12:32 AM
http://demigodllc.com/photo/BSR-2009.04/smaller/D463_0883_img.jpg (http://demigodllc.com/photo/BSR-2009.04/?small=D463_0883_img.jpg)
............... Larger version of above photo. (http://demigodllc.com/photo/BSR-2009.04/?small=D463_0883_img.jpg)

Modern silencers do not touch the bullet, and are very effective at suppressing the muzzle report of the firearm. Some cogent explanations have been offered in this thread, including notably Riss'; however, there is more disinformation.

A standard mil-spec sound test measures the sound pressure one meter to the side of the muzzle (and a bunch of other specifics). Using this test, the best-in-class centerfire rifle suppressors reduce the report vs. a bare muzzle by approx 30-35 dB.

Some have said that while the sonic crack exists, suppression is pointless. This is far from the experience of most suppressor shooters. First of all, from the shooter's/spotter's point of view, the crack is not readily audible unless there is a physical structure (like a wall) to reflect it from downrange of the muzzle. For others in the area, there is no "BOOM" report, as many have mentioned. The sonic crack is typically only audible relatively close to the bullet path, and only in certain spatial relationships to the bullet path.

A suppressed AR-15 is still fairly loud for the shooter because so much noise "comes through" the action. On the other hand, a suppressed bolt gun (such as pictured) is pretty quiet from the shooter's perspective.

A setup like this literally goes "Pfft pfft pfft":

http://demigodllc.com/photo/PURSE-TRAIN/smaller/D462_6158_img.jpg (http://demigodllc.com/photo/PURSE-TRAIN/?small=D462_6158_img.jpg)
............... Larger version of above photo. (http://demigodllc.com/photo/PURSE-TRAIN/?small=D462_6158_img.jpg)


Another way to think about what Riss said in terms of surface area and heat is that a suppressor buffers the pressure, releasing it at a lower peak and average pressure but over a longer period of time.

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