- A quick caveat before we get started here,
I do not want Smarter Every Day to be observed as
a channel that glorifies weaponry.
I am just fascinated by fluid dynamics,
ballistics, optics,
mechanics, aerodynamics.
All this stuff is just fascinating to me.
And I am hard-pressed to find one singular thing
that I can study that wraps all these physical phenomenon
into the perfect Venn diagram that tickles my brain
quite like firearms.
So, that's why you'll see me studying firearms so often
and I hope you realize that I'm doing it as intelligently
and respectfully as I can.
That being said, I've made some observations
in the last episode and I've learned some stuff.
And I've also decided to push it a little further
by studying suppressors.
So, let's look at this and try to get smarter everyday.
First, let's revisit what we learned in the last episode.
Using a phantom camera with a clever photography technique
called Schlieren, which is German for streak by the way,
we observe that the supersonic bullet creates
an angular shot cone and the angle of that cone can
be used to determine the mach number.
We also learned from Dr. Konigstrasse at UAH
that a bullet travelling in the transonic regime
can create supersonic flow around it
because the air has to speed up
and rush around the outside of the surface of the bullet.
This is a connection I didn't make at the time
but we've all see these awesome pictures
of a fighter jet with this cone of vapor behind it,
this is totally why that happens.
The jet is flying along in the transonic regime
just like that bullet and just like the normal shockwave
that occurs on the side of the subsonic bullet
that's happening on the jet.
And it does two things, number one,
it makes this cone of vapor form on the jet
and number two, it makes me all tingly inside.
Okay, so I think we have a good understanding
at this point of shockwaves created by a bullet itself.
You may have heard someone talk about the crack of a bullet
as it passes, that's created by this shockwave.
But if you think about the bang of a gunshot,
it's all those rapidly expanding gases
out the front of a muzzle right?
So it's time to hone in on that area right there
and study that with super schlom,
super slowmo suppressor Schlieren, there you go.
It's hard to say.
In a past episode of Smarter Every day
I asked a company to fabricate a see-through suppressor
so we could see the flame front propagate
through the baffles and try to understand what was going on.
That was effective in showing what happens on the inside
of their particular suppressor design
but what I wanna see is exactly what happens
on the outside of the suppressor,
after all, that's where all the noise is.
Here's my friend Coop firing his rifle
chambered in 300 blackout, both suppressed and unsuppressed.
I want to show you a full minute of slow motion video
because I believe it does the best job of explaining
the physics of what's going on.
On the left we have a suppressed weapon
and on the right we have the same weapon unsuppressed.
When they're first fired you can see straight away
that the weapon on the right seems to have a larger,
dirtier blast but after four milliseconds
there doesn't seem to be any more shockwaves,
we're just venting the exhaust gases at that point.
The weapon on the left, however, is still chugging away.
It's like this initial blast is bouncing around
on the inside of the suppressor
and just a little bit of the gases
are being leaked out with every reverberation.
(gunshot echo)
Watch what happens next though.
On the right, the echo from the unsuppressed weapon
is huge and very distinct.
You can see how powerful and singular
that initial blast was
by how sharp the echo is when it returns.
Imagine that echo entering your ears,
meanwhile you can still see that the suppressed weapon
is dissipating that acoustic energy slowly.
This is like the clearest example I can show
of that energy being dissipated differently.
On the right, the unsuppressed version,
the whole thing's over in a millisecond and a half
but on the left, the same acoustic energy
is dissipated over 15 milliseconds.
That is a direct comparison showing you
that it almost acts like a capacitor in a circuit,
it's like, slowly filtering the energy as it exits.
Anyway, that energy dissipation does not come for free.
Suppressors heat up very, very quickly.
All that thermal energy is captured
because it doesn't dissipate away from the weapons.
So the problem with suppressors is
if you fire enough rounds through 'em,
they heat up very, very fast and they can cause malfunctions
and even damage to the weapon.
Now let's look at subsonic ammunition
being fired from a suppressor.
This is absolutely fascinating.
Okay first observation.
The first thing that leaves the suppressor is unburnt powder
and look at that, there's little baby shockwave,
they're supersonic.
Now whether this is gunk coming loose
from previous shots, or whatever, I don't know
but it's clearly supersonic.
Second, did you see that little vortex ring
poot out the end?
Okay, here we go, bullet time.
We know this is a subsonic round
so we're expecting normal shockwaves
on the sides of the bullet but look at that.
They're not there until the bullet
is several inches away from the muzzle.
It is crazy to think about how complicated
this flow environment is but it's really fun
to make these observations and try to figure it out.
This episode of Smarter Every Day is sponsored
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Is that, what are you doin' right now?
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Big thanks to Hello Fresh for sponsoring Smarter Every Day
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I really like it when this happens
and yeah, give it a shot.
I think you'll dig it with your family, it works for us.
What are these little squirrely things
that come out of the suppressor?
- Okay, so what you're seeing here
on this blackout cartridge is your seeing unburnt
propellant leaving the muzzle before the bullet goes
and so for 300 blackout optimally you get complete
burnout around 9 1/2 to ten inches of barrel length.
So this is a 10.2 inch barrel length
so we're right on the threshold of burning
all the propellant out before the bullet leaves the muzzle.
- But look, there was a supersonic piece of powder
- Yeah there is.
- You see that?
- Whoa!
- This is insane, we're just like, learning important stuff.
Alright, well that was delightful,
what did we learn John? (laughs)
- Propellant outruns bullets sometimes.
You may have grains of propellant
that exit the muzzle faster than the bullet, supersonically.
- That's crazy, and there's a shockwave on those grains
of propellant - Exactly!
- That's uh, never would have thought that.
- Neither would I.
- I hope this episode earned your subscription.
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You're a smart person, you can make your own decisions.
I'm Destin, you're gettin' smarter every day.
Have a good one.