How Stuff Works Presents How Silencers Work

Capture

Now before all of you get worked up over “silencer” in the title, its the title of the video of which (much to their credit), How Stuff Works corrects the viewer that our beloved cans are called “suppressors”. Its a fun video meant for entertainment purposes but if any of our readers have been under a rock, the video does explain suppressors broken-down Barney-style.

Complete with info-graphics, a guy who may actually understand what he is talking about (until he says its a 20 dB explosion), and sound-effects, it will at least entertain you four minutes. Ignore the last thirty seconds which turns into an advertisement.



Nathan S.

One of TFB’s resident Jarheads, Nathan now works within the firearms industry. A consecutive Marine rifle and pistol expert, he enjoys local 3-gun, NFA, gunsmithing, MSR’s, & high-speed gear. Nathan has traveled to over 30 countries working with US DoD & foreign MoDs.

Nathan can be reached at Nathan.S@TheFirearmBlog.com

The above post is my opinion and does not reflect the views of any company or organization.


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  • J.T.

    That hurt to watch.

  • Theo Braunohler

    When I see someone correcting someone else for calling it a “silencer,” that instantly tells me they don’t know what they are talking about.

    They are called silencers by the ATF, by the #1 manufacturer, by the #1 distributor, and by the inventor himself, Hiram Maxim. You may not like the word and calling it a “suppressor” is perfectly fine, but the word “silencer” is absolutely 100% correct.

    • hami

      Some people take every opportunity to correct someone else, often when they don’t entirely understand the concept either. It’s a show of character, in my eyes.

      • Nicks87

        Hmm, sounds a lot like some of the people who comment on TFB.

    • Matt L.

      DINGDINGDING
      I
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      G
      D
      I
      N
      G
      D
      I
      N
      G

    • Jonathan Ferguson

      Totally agree. We still call car mufflers “silencers” here in the UK, despite the obvious fact that they don’t silence your exhaust. The insistence upon “suppressor” (also valid) is silly.

      One note; the inventor was Hiram Percy Maxim, not Hiram Maxim of machine gun fame.

      • steveday72

        @Jonathan Ferguson – Hiram Percy Maxim was the son of Hiram Stevens Maxim – inventor of the Maxim machine-gun.

        • Jonathan Ferguson

          I’m aware of that. Still not the same man.

    • TDog

      But, but, but… it’s not as TACTICAL!!!!!

    • lowell houser

      I prefer the word “muffler.” Think about it, start with a combustion chamber, which exits to an exhaust pipe. What goes on the end of a exhaust pipe? A muffler. De-mystifies the whole thing. Plus insisting on the word “suppressor” makes you sound like a pretentious douchebag.

      • Michel_T

        +1 for “muffler”… it’s also a good way to confuse your favorite elected official.
        If noise is bad, why are some muffler mandatory, while others need special permit and permission…
        😉

        • Sir TuberKopf

          How about we refer to them as hearing protection?

          To so excessively restrict something that can protect the hearing of humans and animals is cruel and abusive to the public at large. And should be considered animal cruelty as well.

    • Dirt

      Some manufacturers and the inventor call them silencers to make them sound more impressive for marketing reasons. The ATF calls them silencers to make them sound more impressive to make them easier to regulate.

      I call them suppressors in part because they don’t make the report silent, they suppress it. Mostly I call them suppressors because hollywood has convinced the uninformed public that they’re completely silent assassin tools, and I want to stress that they’re closer to safety equipment, like ear plugs or car mufflers.

    • Mustascheo

      Eh, semantics.

    • steveday72

      Henry Ford called his first mass produced car the Ford Model-T, that doesn’t mean that every car on the streets is also called Model-T.

      Hiram Maxim referred to his gun-muffler invention as the Maxim Silencer, but “Maxim Silencer” was just the brand product name – a product name that stuck the same way that adhesive backed clear tape, produced under the Scotch brand, is commonly called Scotch Tape in the US (or Sellotape in the UK) regardless of the manufacturer. When someone says “Can you pass me the Scotch tape/Sellotape?” you understand what they mean, but it’s not the accurate name of the item.

    • steveday72

      PS: Hiram Percy Maxim was the son of the machine gun inventor – Hiram Stevens Maxim.

  • floppyscience

    That was physically painful.

    A suppressor reduces a gunshot from 160dB to 20dB? Where can I find these magical things?

    Then there was a revolver being used for illustration, which led him to claim the hammer falling is all the sound the gun itself makes. How about the action of a semiautomatic pistol cycling? That’s pretty damn loud.

    It’s no wonder that people are so ignorant and scared of suppressors when this is the quality of information being presented by a supposed educational source.

    • Jonathan Ferguson

      I suspect they meant BY 20db, rather than ‘to’.

    • The graphics in the video stated that a suppressor reduces the sound BY 20dB. The narrator either misread the info or something. He SAID it reduces it TO 20dB. That is probably the only serious error in the vid – except for the part where he says anyone who calls suppressors ‘Cans’ is probably someone you don’t want to associate with.

      Actually, if you follow the You Tube link you’ll see that he has made the correction at the beginning of the video.

      • Dan Atwater

        He also calls them “whisper quiet” and says that suppressors make guns less accurate.

  • nate

    Nathan S.

    Can you please explain why we should get worked up over the word “silencer” ?? And why you feel we should give them credit for saying it’s actually called a suppressor, when this is false??

    • kyle waters

      Because some people want to give the impression that everyone else knows less than they do and are ignorant. The tacticool crowd also thinks that getting rid of the word silencer removes some of the misconceptions from the general public about silencers,

      • Dan

        Yep like the paintball crowd deciding to call their guns markers so they might be less evil.

  • Larry Mallon

    Powder doesn’t explode, it burns.

    Have to check with SAAMI. Not sure what catridge has maximum allowable chamber pressure of 3000psi.

    • ostiariusalpha

      Black powder is a deflagrating (controlled burning) propellant that ignites degressively, that is, with an ignition rate that rapidly decreases through it’s burn cycle. Smokeless powder is a progressive burning propellant that actually increases the rate it deflagrates at till the pressure in the case reaches the point that the propellant actually detonates. So, yes, smokeless powders “explode.”

      • claymore

        Not true.

        • ostiariusalpha

          All too true in many cases, but it’s generally not something you want to happen. In a firearm, deflagration is maintained below the detonation point by the bullet moving down the barrel and increasing the area for the gases. But if it can’t expand the area fast enough and keep the pressure down due to an obstruction or overcharge then detonation can and will occur. This was the whole point of the video by IV8888 about the dangers of substituting smokeless powder for black powder in muzzleloaders. When Eric & Kevin massively overcharged the rifle with black powder, it simply had a more massive deflagration with no detonation. When they merely substitute a single powder charge with smokeless behind a ball, it detonates and puts a goose egg in the barrel of the gun. Subsequent larger charges of the smokeless powder cause more explosive damages.

          • claymore

            So tell us the detonation speed??????

          • ostiariusalpha

            You could have combined that into one message with the edit function, clay. Anyway, detonations are by definition supersonic ignitions, which isn’t all that difficult for smokeless powders to achieve, or hard to understand. Heated nitrocellulose produces a gaseous ignition medium that, as I mentioned before, deflagrates in a progressive manner; the more heat and pressure, the more fuel the propellant expells. Progressive deflagration is quite prone to detonation by its very nature, with pressure that increases exponentially; this is one of the features of that was exploited for creating high explosives.
            Single-base (nitrocellulose) powders have a detonation velocity of 23,950 ft/s, and double-base (nitroglycerin + nitrocellulose) ball powders have a detonation velocity of 25,260 ft/s.

          • claymore

            AH but that is the point they don’t detonate

          • ostiariusalpha

            Ha ha! To be clear, a firearm shouldn’t experience a detonation when operating normally, but there are plenty of blown up guns that attest that smokeless powder will detonate all too easily.

          • claymore

            No it doesn’t detonate it causes a MECHANIC explosion due to the expanding confined gasses that is all.

          • ostiariusalpha

            No, that is utterly wrong, claymore. A gun will not mechanically disassemble itself (provided it doesn’t have metallurgical problems) during any deflagration. Ever. Only a detonation has the power to crack the steel. Period. I’ll repeat so this is clear, the gun won’t turn into a bomb unless the smokeless powder detonates. Which it absolutely can, and have done so in hundreds of thousands ruined guns ever since smokeless propellant were developed. A subsonic ignition will push an obstruction out of the barrel every time before the pressure can make the metal of the firearm fail; just as in the example of the muzzleloader that Eric & Kevin overloaded with black powder and obstructed with 3 bullets. With smokeless propellants there isn’t enough time to push out the obstruction before the detonation point is reached.

          • Todd

            I assume you are confused about detonation and pressure high enough to cause the gun to physically fail. It’s no different that a balloon, if you increase pressure too high it pops, so does a gun. Nothing else is happening, the air in the balloon doesn’t detonate and cause the balloon to pop. Normal firing of a gun causes the steel of the gun to stretch a but under the pressure, and like a spring it will stretch back. But like a spring, if you stretch it too far it won’t spring back all the way, which happens to some guns and the chamber is forever bloated to some degree. So there you have the reason for bloating and explosions.
            The difference between black and smokeless, as far as being a propellant are concerned, is smokeless can easily generate the pressure to blow a gun. Black is low power in comparo so you’d basically have to plug the barrel to blow the gun. Smokeless is extremely powerful, capable of much greater pressure than the gun can handle, which is why the manufacturing of powder and loading of ammo is very tricky. Black being significantly lower powered you can haphazardly load it by hand in the dark without a measure and it’ll be ok.

          • ostiariusalpha

            No confusion here. A series of overpressure spikes can compromise the structural integrity of the steel, that’s why I mentioned metallurgical problems. The only kind of deflagration overpressure event that can cause immediate rupture in an undamaged gun without detonation is a SPS (secondary pressure spike) that can occur with some reduced loads. The ways that obstructions can cause DDT (deflagration-to-detonation transition) are well studied, I can put up a few links to scientific studies that have been done if you like.

          • Todd

            Thanks but no need for links. It just sounds like you’re saying the steel is capable of handling any pressure and only the shockwave from detonation or a “sps” will harm it. Those will harm it, I’m just saying it’s not only possible to blow the gun with a shock free smooth rise in pressure, it’s likely the reason why most all non defective guns blow. If you say pressure alone can’t rupture the steel then scuba tanks could be 1mm thick and could hold 20kpsi, but the fact is 20k will easily rupture a normal thickness scuba tank.
            So maybe we’re just confused on what you’re saying?

          • John

            My head is exploding from this entire conversation….

            …sorry, my head is deflagrating…

          • ostiariusalpha

            You do seem just a tad bit confused. The difference in pressure curve between a firearm’s pressure spike and over inflation of a tank are substantial. An air tank is obviously not an equivalent to the steel in a gun, but besides that, sustained stress load can cause whatever the vessel (air tank, firearm, balloon, etc.) to fail at a much lower pressure than a momentary increase like smokeless propellants produce. As you mentioned before, an overpressure event can stretch the metal beyond it’s capacity to spring back (exceed the elastic yield strength), but firearms are actually designed to survive this. In order to exceed the barrel’s ultimate tensile strength (fracture or other ruptures) you need to reach pressures that are well past the detonation point of even single-base powders. The exception to this, the SPS, works by sustaining the pressure and thus lowering the necessary amount of pressure that will cause a failure.

          • claymore

            Nope still not a detonation

          • claymore

            So all the pipe bombs ever made with black powder all detonated? Ludicrous on it’s face

          • ostiariusalpha

            Oh wow, claymore, that was ignorant. Pipe bombs are nothing like a firearm as far thickness & quality of steel are concerned. Even on your pipe bomb example, if you use too thick of pipe, it will simply contain the deflagration.

          • claymore

            LOL schedule 2 pipe not strong. And like you just admitted “it will simply contain the deflagration” Note not a detonation.

          • ostiariusalpha

            That’s funny, I don’t see any schedule 2 on the chart. And in case I wasn’t clear enough before, degressive deflagrations like black powders produce won’t detonate.

          • claymore

            And neither does smokeless

          • ostiariusalpha

            Oh, really? Then why is there all that scientific literature about smokeless powder detonation? Maybe you should have told them they were wasting their time before they gathered all that data that shows you’re wrong.

          • Todd

            Are you basing all this on stories like reduced loads of 296 blowing guns? Most reloaders know the real reason this happens. As for steel tanks and guns, do you really think a generic gun is made from steel that is better than an air tank? Pipe bombs using either type of gun powder will always be weaker than a gun because the threads give before the pipe. The powder burns slow enough that odds are the pressure will vent out the fuse hole, which is why people use black because it burns much faster. Still possible black will vent b4 the pipe blows but much better odds than smokeless.
            I guess it is time for those links that explain how smokeless detonates under normal use. Or maybe this whole argument is based on a disagreement of what detonation is? Many would consider all firearm discharges to be detonations.

          • ostiariusalpha

            No, none of that forum BS. I am familiar with some “light loads” being fast powders that are in reality double or triple charges. Some confuse both that and an SPS with an SEE (secondary explosion event, i.e. detonation), but I’m familiar with the difference.
            Detonations are a very well defined phenomenon – a supersonic ignition front through the reactive material. Also, did you even read what I actually posted? Detonations are N-O-T a normal part of the propellant ignition in a firearm, they are a special condition caused by the pressure vessel exceeding the detonation point of the propellant. And yes, the steel of an air tank is not the same as 410 Stainless or 4150 CMV. SA-516-70 is a common steel used in pressure tanks, it’s yield strength is 336 MPa and tensile strength of 510 MPa. 4140 Chrome-Moly has a yield strength of 417 MPa and tensile strength of 655 MPa. 4150 Chrome-Moly has a yield strength 380 MPa and tensile strength of 730 MPa.

          • Todd

            The primer is certainly super sonic and will affect burn but I’ll assume we’re not counting the primer as a factor? So I’d like to hear more since it seems you are not a common troll and actually have something to say. Maybe start fresh and explain to us/me exactly what you mean and why? I guess start by explaining how smokeless can go from burning at a controlled rate to suddenly detonating, and your definition of detonation which varies from person to person.
            Like I don’t follow you here; “they are a special condition caused by the pressure vessel exceeding the detonation point of the propellant” If not a typo then help us out here. Thanx

          • ostiariusalpha

            I’m a fairly uncommon troll, or so I’m told. The first thing that needs to be understood is that many reactive substances that deflagrate under certain circumstances will also detonate under others; smokeless powders are one of them, and you can look up for yourself the numerous others by searching for “deflagration-to-detonation transition” in any search engine. The long, thin channel of the barrel is an ideal geometry for the transition to take place, so any serious obstructions in it can turn the situation quickly toward detonation instead of the intended deflagration. Sealed pressure vessel tests have shown that even in a steel container with only 5mm thick walls most of the smokeless propellants will reach some level of partial detonation before the vessel can rupture from just the pressure of the deflagration.

          • Todd

            K, I googled a few things but not really getting anything of value. My guess is I’m looking for proof about conditions that can cause powder to burn out of control, something that bypasses the inhibitors and allows it to go full nitro on us, right? I always assumed that it didn’t happen, and if it did then it was beyond 100kpsi so nothing for us Joe Blo’s to be concerned with. I get how it works on common stuff like gasoline or other misc flammable stuff, just having a hard time with smokless. For example smokless in a sealed steel container I tested didn’t, it just simply built pressure until the container ripped open. Maybe it wsn’t enough pressure build…
            I’ll read more later but sleeping pill ius kicking in and brain shutting down so talk tomoro 🙂

          • claymore

            Right sure

          • ostiariusalpha

            You know, claymore, you really don’t have to go with your gut whether to take my word for it or not. You can look this stuff up yourself, I’ve supplied plenty of keywords to search on Google for more info.

          • claymore

            AH dude not my gut this was my LIVELIHOOD. I have had more real training in this than you will ever have. No need for me to google I did it for a living.

            Try this simple experiment take a pile of a pound of black powder and set a blasting cap in it and see if there is a detonation NOPE then the same with smokeless gunpowder same result NO DETONATION

          • claymore

            Very simple to know does one need a blasting license for handling black powder NOPE how about smokeless powder again NOPE the reason being is they are not high explosives, you know the ones that actually detonate, they are low explosives that by definition do not detonate.

          • claymore

            One last point and I am done with you. The proper authorities determined, through testing, that my training, experience and skill levels was sufficient to issue me a blasting and explosives license allowing me to use and purchase low and high explosives that I determined were needed for jobs. How about you you ever hold one?

          • claymore

            Still not a detonation that is a mechanical explosion only.

  • Kevin

    What’s up with that crack about “people you probably don’t want to associate yourself with?” Every other guy I know that calls them ‘cans’ are stand-up guys with good morals and happy families. This dude needs to do some real world research.

    • JLR84

      Only gun people call them “cans”. It’s a safe bet he isn’t a fan of ours.

  • Joel. K

    in sweden we call them signature muffler or sound muffler, a good choice if u ask me. Because thats exactly what is does, it muffles your signature for in sound and in flash.

  • Dan

    I was under the impression that suppressors increase accuracy by providing a more consistent atmosphere for the gasses to expand in.

  • Vitor Roma

    Oh my, he says that a supressor reduces power and accuracy, he did some lazy and awful research.

    • aka_mythos

      When people repeat these words of “wisdom,” it important to consider what exactly is being compared. People incorrectly assume and test the adage by firing the same rifle with and without a suppressor and then see a slight improvement in power and accuracy with a suppressor over shooting it unsuppressed as proof to the contrary. That improvement comes from the fact that even though the suppressor reduces the forward velocity of expanding gas, that gas continues to induces pressure beyond where it otherwise would have reached the barrel’s end. The suppressor is in effect a less efficient barrel extension. What this “reduced power and accuracy” actually refers to is whatever loss in power and accuracy is apparent when you compare a 10.5″ barrel with a 6″ suppressor against a similar rifle mounted with a 16.5″ barrel. In a sense they’re comparing a 16.5″ barrel to a 10.5″ barrel with a little bit more stability.

  • anon

    >a 20 decibel explosion with just the hammer clicking

    no.

  • I “love” talking to people that think they know about silencers.

    Like the guy who corrects me about calling them silencers.

    Or the guy that insists that they lower accuracy, and bullet “power.”

    Or the guy that insists I can use it to murder someone in bed without waking their wife.

  • SnakeEater-0317

    1) I call them cans… my bros (not the frat house type) call them cans.

    2) There is a process called Free Bore Boost which actually occurs when utilizing a suppressor, not only does it increase accuracy but it can increase the velocity of the projectile (depending on the platform) by up to 50 fps.

  • TheNotoriousIUD

    That guy is a dipsh-t.
    Everyone I know, including myself, calls them cans.
    And who cares what anyone calls them anyway?
    If I pay $1200 for one ill call it my “Magic Sound Eraser” and everyone can kiss my a-s.

  • aka_mythos

    The whole suppressor versus silencer argument is a semantic one. The distinction is colloquialism versus some vain attempt to sound smarter or more precise. Our language is nebulous and abstract; one where many words have multiple meanings and multiple ideas have multiple singular words to describe them. Some say car, some say automobile, vehicle, clunker, or buggy… while they might not be precise you still grasp what they’re conveying and to pretend to the contrary is just being obstinate.

  • Geoffry K

    Call it what you want, can, muffler, suppressor or whatever, but the ATF says it is a “silencer” in the regulations, so that is the legal name as far as they are concerned.
    You better put “silencer” on your Form 1 or Form 4, I did, and I don’t know if “suppressor” would be accepted.

  • Taofledermaus

    People just go nuts any time someone uses a colloquial term for anything. People love to correct other people on the internet. When they do it face to face, they stop getting invited to go shooting with their buddies.

    • Dan

      Or eventually end up missing a tooth or having their nose pointed in a different angle. I cannot stand people that go to such lengths to make themselves look smart. I don’t care what the correct term is. I don’t care if someone mispelled a word or forgot/misused punctuation. As long as the information is accurate who cares.

  • nom

    basic principles are met.

    They added the correction for decibels in an annotation, and for anyone who doesn’t know a thing about guns it explains it simply enough.

  • ClintTorres

    This guy is stiffer than his woody for misinformation.

  • Slim934

    While the ATF does formally refer to it as a silencer, I personally do not use the term simply because of the connotation it sends to the layman who does not know any better. “Silence” creates the impression that it actually DOES silence it, and because the average rube’s knowledge of silencers come from movies which ingrain this incorrect belief I prefer to use the alternative term simply because it gets people to MAYBE think differently than what the latest schlock out of Hollywood is trying to tell them. Or atleast ask the question. Most people however do not (in my experience) associate the same connotation with the term “suppressor”.

    I do not begrudge people who call them silencers though since that is the legalese term for them.

    Also “don’t want to associate with people who call them cans”? Screw him and the horse he rode in on.

    • Dan

      I show layman videos then ask them how just how”silent” they think it is now. It’s more effective.

      • Slim934

        If I can’t do that, then I think of things that are roughly as loud as a silenced firearm that the average person knows are loud, and ask them if they think those things are “silenced” in any way. That typically gets the point across.

  • MR

    Glad I read the comments first, this seems not to be the bait I want to be clicking on.

  • Ken

    Look at that effective teacup lady grip lol. A lot of good that support hand will do.

  • Mustascheo

    What’s wrong with calling them a “can”? I’m kind of curious why this liberal douche bag sees the need to imply that a suppressor owner may kill you?

  • phauxtoe

    you should do a video on “How Lighting Works”, you Video Lighting SUCKS!

  • Todd

    So like my previous google searches I didn’t see anything that applied except that last link which I did see before but discarded it as not relevant, which it isn’t. Even you said that pipe bombs are nothing like a firearm. If anything the article suggests that guns do not detonate.
    So I still see nothing whatsoever to change my mind, but still open to input… Maybe try explaining it better, like why is it that a detonation is needed to blow the gun when (as you wrote) a detonation put a goose egg in a barrel. Wouldn’t a detonation have blown the barrel? Isn’t a goose egg exactly what I was describing earlier about being stretched too far and it won’t snap back?

    • ostiariusalpha

      I see that I have to break this down a bit Barney style, but that’s okay.
      The first thing you have to be clear on is that a gun with an obstruction in the barrel can no longer be considered as a mere firearm, it is now much closer to the kind of pressure vessel that the military refers to as an enclosed bomb (which most pipe bombs actually aren’t because of their open fuse holes). Secondly, if you actually read any of that material then you should be clear on the fact that, yes, single-base (NC) and double-base (NC+NG) propellants do indeed detonate, especially inside enclosed bombs. You’ve given me some reason to doubt how much you really read though, because Beggs’ article had appendix material that mirrored the content of the study by Dr. Okada’s group which you claim that you found relevant; in fact, one of the appendices is by Dr. Okada (pgs. 42-49). An obstructed firearm is in many ways a more ideal enclosed bomb than even the test sample mechanisms used by Okada or the other European studies. They used electrically activated black powder charges as the primary explosive to initiate deflagration in the smokeless powder, which are much less energetic than what the priming compounds that are used in ammunition put out. And whereas they achieved detonation using thin walled steel tubes (3mm-5mm thick, depending on the group doing the testing) a firearm has much thicker walls on it’s barrel & chamber, all of which leads to a higher ratio of propellant detonating. In a deflagration-to-detonation transition, you will always have a certain percentage of the propellant consumed in the deflagration stage over whatever is left to carry out the detonation; you can have 50% of the propellant consumed in the deflagration stage with the rest detonating, or you can have 99% consumed at deflagration with only a 1% propellant amount detonating. The ratio can vary wildly based on initial conditions, such as vessel volume & geometry, the primary explosive used, the amount of propellant used, the granular geometry of the powder, and (importantly) the particular powder formula used; all these effect the point that detonation will take place. With thin-walled vessels, some powders will rupture the vessel with deflagration pressure before much of any detonation will occur, but a thick walled vessel like an obstructed firearm will contain the pressure on a huge swath of different powder types with an exponentially greater certainty of reaching the detonation point. Which brings us finally to the amount of damage that can be expected in a firearm detonation. In the case of a very minor detonation (<2% of the propellant achieves detonation) you can expect deformation of the vessel (goose egging the barrel) without necessarily a rupture, but as the ratio of powder that detonates goes up (by using more powder, for instance) you get increasing levels of damage to the vessel. You know you have achieved a high ratio of detonation if the chamber itself instantly disintegrates during the explosion.
      I hope this clarified it at least a little bit for you, but if you have any more questions I'd be happy to keep going.

      • Todd

        Everything you just said I can more or less agree with, but I still don’t understand a few things: I still don’t understand what the difference is when the burn thru the powder is supersonic vs subsonic. Meaning as far as the the powder or gun is concerned what do they care if it’s 99% SS or 100? It just seems to me it’s a line someone drew to separate the two, which I imagine could’ve been 5, 10 or 20kfps instead. Maybe it’s because SS explosions are louder so they thought that’s a great threshold. So is it a threshold decided by man, likely before smokeless was invented, or does smokeless actually change at SS? I don’t count solid rocket fuel and those tests, just too different, but maybe the phenomenon is identical, I just don’t know because I don’t know if it exists. Btw, what speed is this SS effect in fps?
        So basically I only see the powder burning faster as pressure and/or heat rises, so maybe a square or cube rate of burn to pressure/heat? So exponential burn rate I get, just not some line in the sand where everything changes. If it does change at SS then what exactly changes?
        As far as the gun is concerned you can use SS primer material, which we can agree detonates, to fire a bullet, but just like using too fast a powder it is not ideal. I have because I’m extremely curious. I do believe the speed of the explosion is a factor on the metal, but that’s not what we’re talking about is it, we’re talking about the powder itself correct?
        I dismissed the info about solid rocket propellant because that’s like comparing a piston engine to a turbine engine, just too different to compare. The pipe bomb is closer but still irrelevant imo because it’s forcing the powder to build pressure exponentially until the pipe ruptures, and being smokeless it will rupture. That “witness” metal was apparently designed to break once SS is reached, but so what? It was designed that way, so if it was harder or softer it would break at different pressures or shock that it sees. So again I just see a man made threshold. Not all those tests broke the witness plate so doesn’t that show SS is not needed? Lets say all powders were twice as slow burning, then none would’ve broken the plate yet still all pipes would blow. If the pipe was thinner or softer it would’ve changed the results too so it seems the whole test was just a guestimate based on a man made threshold. Now if they had a way to measure pressure, heat and burn speed and make an accurate graph it would be a zillion times better. As it is it sounds like saying all SS bullets break beer bottles, which is generally true but not always. If the bullet is lighter and softer then no. It’s not like SS is a magic line that causes all bottles to break. So filling a pipe will blow it, but SS is not required. If inhibitors reduced the speed to a max of 1fps it would still blow.
        Even if smokeless does suddenly burn out of control once the heat and pressure are high enough, which it seems to me you are saying SS is that point, how is that a concern for Joe Blo if that is only attainable by mistake which would blow the gun regardless?
        So I guess the root of my questions are; what changes occur to smokeless at SS, what speed is SS, and whatever happens how is it possible to achieve without an error in loading?
        As for the goose egg, I disagree. I believe the powder burned at whatever rate +-SS it doesn’t matter, but the expanding barrel dropped the pressure just like a bullet moving out of the case does. If there had been more powder or the metal was thinner or more brittle it may have blown. If the metal was stronger it may have forced the blockage out of the way instead, especially if a slower powder was used. So imo it has nothing to do with what speed or if 1% or 10% of the powder crossed that line into detonation. I still see nothing but pressure as the cause, pressure that would’ve happened regardless of speed.
        Thanks for sticking it out, most people would throw some insults or vanish by now. Again I’m open, but just not seeing it.
        Maybe we’re both right but misunderstanding each other, just not sure.

        • ostiariusalpha

          I don’t mind too much, but if you seriously want a better understanding than you can get from a random commenter on a blog, then you should really pick up a book that has both more comprehensive and detailed instruction on explosive combustion.
          Anyways, the ignition propagation rate is in a vastly different classes between deflagration and detonation. In a deflagrating explosion, the ignition is through heat transfer (which is always subsonic). There’s some difficulty surrounding how the different smokeless formulations tend to vary greatly amongst themselves as to the velocity curve they progressively burn at because, while they all accelerate their burn rate as heat & pressure increases, they also all have different reactions at certain sections of their ignition cycle and in different chamberings (vessel volume & geometry). So one powder can start at a slower burn rate than another powder and then increase it’s acceleration at a much faster rate; while the other powder can start with the faster acceleration but not increase it’s burn rate as exponentially as the first powder. They also react differently in the varying charge weights and diameters of different chambers and barrels, i.e. a powder than burns faster than others in a .32 ACP cartridge won’t necessarily be the fastest in a .44 Magnum cartridge, much less a 12-gauge shot shell. Different primers also effect burn rate acceleration. Still, conveniently setting all those complications aside for the moment and just looking at a very fast burning double-base powder like Red Dot, in a 12-gauge AA shot shell hull pushing 1 1/8 oz of lead shot with 21.5 gr of powder you get a top deflagration velocity when the pressure reaches over 10,000 PSI that has been measured at an embarrassingly slow 3 ft/sec. That’s right, the heat transfer front only moves at 3 ft/sec! That’s why having the primer spray hot material on a large segment of the powder load is so important for a good burn initiation. Thankfully, the shot load itself depends on the PSI generated in the gun for it’s velocity instead of the propellant’s deflagration velocity. Now, there are triple-based powders (typically NC+NG+Nitroguanidine) used regularly in artillery that burn faster than any smokeless powder you might use in a small arm; also other propellants that aren’t based on nitrocellulose that can deflagrate still even faster, but at most they can achieve a velocity of Mach 0.03.
          So let’s compare that to the detonation velocity. As I mentioned before, single-base powders have a detonation velocity of 23,950 ft/sec and double-base powders have 25,260 ft/sec. That’s several orders of magnitude faster than the heat transfer velocity and it no longer is merely putting out a rapid rise in pressure (expansion wave), it is releasing a supersonic kinetic shock front (compression wave) through the plasma gas from the propellant into the wall of the vessel. This seems horrifically destructive, and it often is, but like all detonations, the amount of propellant that actually detonates determines the energy that is put out. C-4 and TNT are very powerful and destructive detonating explosives, but how dangerous is a microgram of either one? They won’t rupture a rifle barrel, that’s for sure, and neither will the detonation of a very low ratio of the smokeless powder. As the percentage rises of propellant that is consumed by the detonation instead of the initial deflagration, you get increasing amounts of very peculiar damage.
          As much as I’ve enjoyed this discussion, I’ll have to bring it to an end here. Like I commented at the beginning, read a book if you are truly serious about deflagration-to-detonation transitions.

          • Todd

            Thank you for taking the time, seriously… Very interesting and you’ve opened the door for me about the possibilities, but you’re right about me needing to read more about it. I love this kinda stuff so I will look into it.