I was thinking about how fire guns are very loud and how its worst in close environments (I had never shot a gun cuz im not american) and I remembered the Mirror room scene in John Wick Chapter 2.
I was thinking if by shooting once, many mirror could break because of the sounds of a gun alone. Has someone tried this or see it happen?
Well, my military experience says glass can feel safe from regular gun sounds.
We were using H&K AG3 with 7.62mm ammo, which is pretty strong as guns go. Both outdoor and indoor ranges. Bottles, windows, my glasses, windshields, mirrors, never had anything crack.
So it would have to be a very constructed setup and very brittle glass for it to break glass.
FYI, the H&K variant is called G3A3. AG3 is a noggie term for the licensed design named “Automatgevær 3”, which are locally manufactured.
Source: I’m also a noggie and former AG3 enjoyer.
noggie
From urban dictionary, lol:
Noggie
Mildly derogatory word for Norwegian.
That Noggie sure eats a lot of waffles.
That’s OUR n-word. it’s offensive if someone else uses it.
Ah, thanks. I thought one was the “international name” for it.
It’s possible but not likely or common. Glass is stronger than most people give it credit for. Most “hollywood” glass is actually panes of sugar. You could certainly arrange things so that the gun’s pressure wave has a good chance of stressing and breaking glass, but it would take special preparations and effort and the gun would probably have to be very close to the glass. It’s almost unheard of for it to happen normally unless you specifically shoot at the glass.
Someone like mythbusters could probably test this pretty effectively, but based on my experience around guns and glass, I suspect they’d come to the same conclusion.
A not directly related but still interesting video was done by the slowmo guys on youtube
In theory? Yes.
In practice? Probably be easier to bash it in?
It’s not the frequency that matters, it’s the pressure wave. When any gunpowder-based weapon fires, the expanding gassed from the sudden conflagration of gunpowder doing its thing, right?
Those gases keep expanding even after leaving the muzzle. You can see that in this picture of the USS Iowa firing- the muzzle blast expands spherically and the displacement on the water creates a shallow depression.
If that blast was strong enough and sharp enough, it could break glass, yes. It’s dubious that any standard firearm could just from the muzzle blast alone. But you make a big enough gun with fast enough powder… sure.
Technically, yes.
Soundwaves are made up of pressure waves. A pressure wave results from the explosion of the propellant of a firearm’s ammunition. The explosion works just like any other explosion, creating an overpressure blast, which is the fast onset of a pressure wave. If the glass is hit by such a pressure wave, it can break.
However, the explosion created by ammunition tends to be fairly small, and in a bare barrel is widely dispersed. The pressure quickly dissipates.
What would cause a break to happen would be if a gun were fitted with a muzzle brake, picture here(It’s the square dealie on the very end of the barrel). The vents on the side of the brake funnel the pressure wave tightly in a specific direction. If glass were in the path, yes it could break. Higher caliber means, generally, bigger explosion, which means more pressure.
Here is a video example of it happening to a tail light. I understand it it plastic not glass, but I think you get the idea. Youtube link, I apologize. Video. The muzzle brake is right up against tail light in way way that funnels the pressure wave directly at it. This is possible through a combination of a very large caliber firearm and very close contact to the object. Reduce the caliber and/or moderately increase the distance, and the outcome will change.
This is not the stereotypical “high pitched resonance makes glass shatter” situation, this is the energy being funneled to make a pressure wave shaped hammer situation.
I can’t believe you pulled a real-life example out of your butt. Great explanation!
I was shooting my AR-15 this weekend, and from the table to the campfire, it was blowing clouds of dust. To be fair, I have a silly muzzle device on mine. A “loudener”, if you will
Sound waves are energy traveling through the air. Energy is what causes stress, strain and failure in materials. Yes, a loud gun, especially at the right frequency, could break things with a relatively low failure point.
Explosions frequently break glass and a gunshot is basically a small, controlled explosion.
Small being the operative word. Gunshot explosions don’t have enough energy to break glass in most circumstances.
Harmonic frequencies bro its all in the vibes
I think you are assuming a lot of things here. Modern guns and modern glass, for instance.
The answer probably needs to have a whole lot of “it depends”
What kind of firearm, what kind of glass, thickness of the glass, how far away was the gun when it was fired, etc. will probably all have an effect, and maybe even some more exotic variables, resonant frequencies, atmospheric conditions, temperature,angle you fired the gun at relative to the glass, etc.
Glass absolutely can be broken by vibrations and pressure waves similar to those made by a gunshot, and I would probably expect a high caliber supersonic round fired within inches of a thin piece of weak, brittle glass to break the glass, and on the opposite end of the spectrum, a low powered subsonic round fired far away from a thick piece of strong tempered glass I would expect to have little to no effect whatsoever.
Those are both fairly extreme examples, and I certainly don’t have the science/mathematic background to tell you where the limits are in the middle.
I wonder if the discharge of a regular firearm would shatter movie glass — it’s essentially sheets of sugar, designed to crumble easily without sharp edges. Doesn’t take much force to break it and it’s not as flexible as real glass.
Define “gun”.
If you’re okay with scaling up, then the answer is yes. M777s can easily break glass for any windows nearby.
Certainly if you use a big enough gun.
With a pistol or normal gun, probably nothing will happen.
With an anti material rifle you might get some luck if you are close enough.
Or you just take a tank cannon or artillery, those should have plenty of muzzle blast.
This is a good question and it certainly has me stumped.
ChatGPT says it’s possible and that it’s “not uncommon” for this to happen. It calls the phenomenon “acoustic or sonic glass breakage.”
Yet, Myth Busters disproved it in one of their episodes.
https://mythresults.com/curving-bullets
If I had to wager on it, I’d place my money on the Myth Busters having the correct answer and not ChatGPT, however.
Sound waves are pressure waves. Pressure waves are part of the mechanic of an explosion. Can an explosion break glass? Yes. Then the question becomes what variables to get it to happen. The pressure of a gunshot tends to disperse in all directions at the end of a barrel. However, a muzzle brake funnels that pressure. If a caliber is large enough to have enough pressure, if piece of glass is in the way of that funneled pressure, and is close enough that the energy hasn’t dissipated, then yes. The example would be a high caliber gun with the muzzle brake right next to a piece of glass, preferably a piece of glass that is not able to simply be tossed by the blast.
It is a very specific circumstance, but possible. It’s not going to be “Opera singer shatters glass with resonance” it’s going to be more like using a wave as a brute force hammer.
Unless you had a muzzle that specifically created resonanting waves at the glasses harmonic frequency, and a bunch of glass with the same resonance would all shatter even with a sound wave as small as a voice (much less a gunshot)
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A sustained frequency can do it, but I’m not sure if a gunshot could be harmonic or if they just have 1 main pressure wave (and mostly just noise elsewhere)
Yeah. But the frequency of the sound has to match the resonance of the glass. Any sound can break any glass if they resonate strongly enough to make the glass vibrate violently enough to break. This is pretty hard to do, even when you can control the acoustics of the sound being using to shatter the glass (IE when a singer breaks a wine glass). Finding the right gun and right glass to make it work would be like finding a needle in a haystack.
Using a large enough gun that creates a sonic boom I’m not sure counts. It’s not the sound itself that is breaking the glass at that point, but the concussive force of the wave traveling at high speed.
Guns would break glass by essentially turning air into a hammer rather than resonance. Also lots of rifles are capable of firing bullets that make sonic booms, it’s just not that powerful when it’s a tiny bullet.
Basically every modern cartridge is supersonic unless they’re specifically underpowered to make them subsonic.
The smallest thing you’re going to regularly encounter is .22 LR- for context this is the kind of thing you’d use to hunt very small animals- and even that straddles the line of super/subsonic.
Basically what I’m getting at is that it doesn’t need a “large gun”.
