Speaker 1: Get in touch with technology with tech Stuff from how
Speaker 1: stuff works dot com. Hey there, and welcome to tech Stuff.
Speaker 1: I'm Jonathan Strickland. I'm the host of this podcast. I'm
Speaker 1: executive producer at how Stuff Works, and I heart radio
Speaker 1: and I love all things tech. Into this time for
Speaker 1: another classic episode of tech Stuff. This episode originally published
Speaker 1: on April eight, two thousand and twelve, and Chris Pallette,
Speaker 1: my former editor and co host, and I decided to
Speaker 1: sit down and talk about the science of ballistics and
Speaker 1: using a ballistic forensic science too to investigate a crime scene.
Speaker 1: So you are about to hear this classic episode where
Speaker 1: Chris and I kind of dig down into this very
Speaker 1: interesting field. I hope you enjoy. We did a podcast
Speaker 1: on nuclear weapons recently, Yes, we did, um, and right
Speaker 1: in the middle of it, for reasons that I can't
Speaker 1: even fathom, I started thinking about other kinds of weapons
Speaker 1: and I thought, you know what, it would be kind
Speaker 1: of interesting to do a podcast on ballistics, which is
Speaker 1: basically the science of figuring out moving stuff projectiles work. Yeah, yeah,
Speaker 1: I I was. I agree, that was a cool idea. Yeah,
Speaker 1: it's the science of deals with motion of projectiles. But
Speaker 1: of course it's been used. Sorry, I didn't mean it
Speaker 1: interrupt I was gonna say that, you know, ballistics, It
Speaker 1: also is kind of shorthand for a specific branch of forensics. Yes,
Speaker 1: which is really what we're focusing on today. Yes, because
Speaker 1: when you get down to it, the actual study of
Speaker 1: ballistics is in large part a matter of physics. Yes. Yes,
Speaker 1: there's a lot of science involved in this. We know
Speaker 1: how we much we hate science, dad gum it um.
Speaker 1: Unfortunately for the scientists, but fortunately for h crime mystery writers.
Speaker 1: Bullets do not always behave themselves in terms of physics. Like,
Speaker 1: they generally go where they're supposed to go, but they
Speaker 1: don't always follow the normal path when they get there. Yeah,
Speaker 1: let's just say that it's all due to little, tiny
Speaker 1: individual differences on a very small scale. Because we don't
Speaker 1: mean to say that bullets somehow defy the laws of physics. No,
Speaker 1: but they don't always. They do always travel a predictable path,
Speaker 1: right right. You might think, oh, well, if so and
Speaker 1: so was standing here and shot such and such over there,
Speaker 1: then the bullets should be right here. That's that's not
Speaker 1: always the case. Even even saying the cartridge for the
Speaker 1: the case for the cartridge should be right here. That's
Speaker 1: not always the case either. So to really understand this,
Speaker 1: first of all, we need to talk a little bit
Speaker 1: about how the forensics part of ballistics all came about
Speaker 1: in the first place. Yes, and and really ballistics people
Speaker 1: have been trying to get the science behind uh forensics
Speaker 1: ballistics down for quite some time, but it hasn't really
Speaker 1: been that long that we really got it down pat.
Speaker 1: I mean, in the nineteenth century, Uh, there were people
Speaker 1: who were trying to figure out how to do this,
Speaker 1: but they were the methods they were using were not
Speaker 1: at all scientific, right, And to understand how you would
Speaker 1: be able to use ballistics to try and identify a
Speaker 1: weapon that fired a particular projectile, you have to understand
Speaker 1: a little bit more about what goes on with these projectiles.
Speaker 1: So sometime around oh, the late fifteen century, uh, the
Speaker 1: people who were creating firearms at that time discovered something
Speaker 1: which was that if you were to have a barrel
Speaker 1: of a weapon have some grooves in it to help
Speaker 1: direct the projectile to spin as it comes out of
Speaker 1: the barrel, you improve the stability of that projectile's flight. Yeah.
Speaker 1: Previously they were what you call smooth bore which was
Speaker 1: basically a a smooth tube. The inside of it was smooth,
Speaker 1: so you would, uh, you know, say take your musket
Speaker 1: and fire a shot, fire a shot from it. Um. Actually,
Speaker 1: you know this is this is I was getting ready
Speaker 1: to dismiss this in my head, but I think we
Speaker 1: should mention this. Um. You know those early muskets where
Speaker 1: you would you know, uh, you'd have to get everything ready.
Speaker 1: You'd have to put the wadding and the and the
Speaker 1: powder in and then the musket ball and tamp it
Speaker 1: all down with the rod before you could fire the weapon.
Speaker 1: You know, whether it's matchlock or flint lock, which we
Speaker 1: talked about in another podcast. Um, but you have a
Speaker 1: basically a roundsh ball made of lead which is fired
Speaker 1: using um, the explosive gunpowder and the the gases propelled
Speaker 1: the ball out of the tube, and you know they go, well,
Speaker 1: they go where they go. They generally go in the
Speaker 1: direction that the barrel was pointing. Yes, more specific than
Speaker 1: that we cannot naked. Yeah, they weren't nearly as accurate
Speaker 1: as a rifled barrel, which is what which is what
Speaker 1: Jonathan was just talking about, where they there are grooves
Speaker 1: inside the barrel and they are um, and they travel
Speaker 1: in a spiral patterns. I remember, correctly, didn't we talk
Speaker 1: about something in the rim when they started grooving the barrel?
Speaker 1: But they weren't. They weren't in a spiral pattern. They
Speaker 1: were straight. It might may have been I remember, I'm sorry,
Speaker 1: I just came to mind. But eventually they did hit
Speaker 1: onto the fact that a helical groove spiral groove would
Speaker 1: h helical'd on where where that would create enough spend
Speaker 1: so that the projectile would become much more stable off
Speaker 1: Like this is the same sort of idea you get
Speaker 1: when you have a football player throwing a football, absolutely
Speaker 1: American football. American football player, Um, how to touch the
Speaker 1: ball with your hands? You know when you hear about
Speaker 1: like when you hear about like a tight spiral that
Speaker 1: helps that projectile, in this case the American football maintain
Speaker 1: a precise flight path. Well, while that was very useful
Speaker 1: in making firearms more accurate, it was not thought of
Speaker 1: as a way of identifying a firearm based upon a
Speaker 1: projectile that had been fired for several centuries. It wasn't
Speaker 1: until the eighteen hundreds. Yeah, and uh, actually I have
Speaker 1: the earliest and this this is all from a website
Speaker 1: called Firearms i D. And it was created by a
Speaker 1: guy named Scott Doyle who did some amazing research on ballistics,
Speaker 1: the history of it and all of the elements that
Speaker 1: go into identifying firearms. If you are interested in the subject,
Speaker 1: I recommend you check out Firearms i D because it
Speaker 1: is truly exhaustive. I'm only going to give a small
Speaker 1: fraction of what he made available. So the earliest event
Speaker 1: he found, the earliest documented case of identifying a firearm
Speaker 1: UH in a criminal case happened in eight in London,
Speaker 1: and what had happened was a homeowner was killed by
Speaker 1: by a gun and a servant was suspected of being
Speaker 1: the perpetrator. And UH a fellow named Henry Goddard UM
Speaker 1: who was with the London Police or with a branch
Speaker 1: of the London Police, was assigned the case and he
Speaker 1: examined the the the projectile that killed this shop owner
Speaker 1: and determined that it was made by a particular mold
Speaker 1: um by UH, which meant that it came from a
Speaker 1: specific company. And then he looked at the paper patch
Speaker 1: that was used in the the the firing as well. Now,
Speaker 1: this paper what it did was it created a seal
Speaker 1: between the powered and the projectile so that when the
Speaker 1: powdering knights and the gases expand, the projectile would have
Speaker 1: a good seal on it, so it would it would
Speaker 1: fly out properly. And you saw that this paper patch
Speaker 1: had been made from some newspaper that had been in
Speaker 1: the room. He actually found the page where the newspaper
Speaker 1: had been torn to make that patch, and so they
Speaker 1: were able to determine that it was in fact the
Speaker 1: servant who appeared to have fired on this shop owner.
Speaker 1: And so that was the first case. Now in that case,
Speaker 1: it wasn't an idea, you know, specifically checking the bullet
Speaker 1: for the spiral marks that would indicate, um, what gone
Speaker 1: fired it, because that's that's something else we should mention.
Speaker 1: These rifling marks, uh ifact, That's why we call it
Speaker 1: a rifle. There's these rifling marks that are on the
Speaker 1: bullet itself. That's that's caused as a bullet travels down
Speaker 1: this this grooved barrel, it cards little scratches into the bullet. Yes,
Speaker 1: and so these scratches are unique to a particular weapon.
Speaker 1: Even even two weapons of the same make and model
Speaker 1: will produce different scratches, at least on a on a
Speaker 1: tiny you know, beyond a superfluous glance, you'll be able
Speaker 1: to see that there are differences, and so it's almost
Speaker 1: like a fingerprint. If you are able to see, you know,
Speaker 1: tell that two different bullets are close enough and identity
Speaker 1: that these these markings are really really, you know, to
Speaker 1: all intents and purposes identical. You can say that they
Speaker 1: were both fired by the same weapon. So if you
Speaker 1: happen to have that weapon in your possession and you've
Speaker 1: done a bunch of test firings and all the bullets
Speaker 1: are coming out the same way and they matched the
Speaker 1: bullet that was used in a crime, you can feel
Speaker 1: pretty confident saying that that, in fact was the weapon
Speaker 1: that was used in that crime. Um. So yeah, I
Speaker 1: mean there, Um, there are many cases in which you
Speaker 1: know this has been this has been used. I mean
Speaker 1: one of the first I read, and I read an
Speaker 1: excellent article by Katherine ramsland um in uh in which
Speaker 1: she was talking about do you remember learning about Sacco
Speaker 1: and Vanzetti in your American history class? This very controversial?
Speaker 1: Absolutely absolutely, Um. This was a case in which, uh, Um,
Speaker 1: the payroll was being delivered to a shoe factory and
Speaker 1: a a couple of guys came up and shot the
Speaker 1: guards and UM, you know, they basically made off with
Speaker 1: the money and UH so they started looking for information.
Speaker 1: This by the way, was April fifty, UM, and this
Speaker 1: is when they started looking. Uh. This really was the
Speaker 1: incident that made modern ballistics a science, I think, UM,
Speaker 1: just from from the way they handled it. So UM,
Speaker 1: the investigators behind this uh collected all the evidence they could,
Speaker 1: including the the spent shell casings. UM. They went back
Speaker 1: to looking at the manufacturers of of weapons. UM. There
Speaker 1: were about six at the time that they looked at,
Speaker 1: and uh they turned out to be Remington, Winchester, and
Speaker 1: Peters UM that that could use these these casings. UM.
Speaker 1: And what they what they ended up doing was they started,
Speaker 1: uh you know, looking around at you know, what they
Speaker 1: could get from this information. And as it turns out,
Speaker 1: one of the incriminating factors was the fact that for
Speaker 1: one of the weapons that they had, the only bullets
Speaker 1: that they could find, uh that would fit that weapon
Speaker 1: or in Psacho's pocket. UM, which is pretty incriminating evidence,
Speaker 1: but it's not exactly that's circumstantial, you know. UM. So
Speaker 1: what they did was they talked to somebody who had
Speaker 1: worked with uh sort of preliminary ballistics technology. His name
Speaker 1: was Albert H. Hamilton's and UH he actually had been
Speaker 1: UM working with UH with other cases and UH he
Speaker 1: wasn't completely scientific um in his methods, but he he
Speaker 1: actually got stuck in the middle of the case and
Speaker 1: during this UH the Sacco and Vanzettie case, UM came
Speaker 1: in with new weapons that were uh similar to the
Speaker 1: ones that they had and and basically disassembled them in
Speaker 1: front of the judge who noticed that he was swapping
Speaker 1: parts with the other gun and went, no, you can't
Speaker 1: do that, and they threw it out. But they did
Speaker 1: give the information to Calvin Goddard, someone who is quite
Speaker 1: famous in ballistics forensics. Yeah, he's he's I would argue
Speaker 1: that he's probably considered by many people to be the
Speaker 1: father of this technology. He worked with a guy named
Speaker 1: Charles Waite at in New York with the Bureau of
Speaker 1: Forensic Ballistics, and he was using microscopes and a helixometer,
Speaker 1: which is a probe that you could use to look
Speaker 1: at gun barrels. UM. I imagined that was used in
Speaker 1: the manufacturing of these weapons. UM. But what he did
Speaker 1: was he fired these the weapons used or or in
Speaker 1: Sacco and Vanzetti's possession um into a lot of cotton
Speaker 1: and compared the casing and the bullet to the ones
Speaker 1: recovered in the investigation, and they were similar enough, um
Speaker 1: to incriminate both of them. Now, um, Vanzetti, I mean,
Speaker 1: they put both of them to death. But Vanzetti said
Speaker 1: he was innocent, and uh apparently Sacco's uh last words
Speaker 1: were long live anarchy, which doesn't exactly uh he he
Speaker 1: doesn't exactly say, well, you know, I didn't do any
Speaker 1: of that. But yeah, and in later years too, they've
Speaker 1: still they continue to examine that and uh, right now,
Speaker 1: although it's still controversial whether or not these guys were
Speaker 1: railroaded or whether or not they actually did commit the crime. Um, Uh,
Speaker 1: they still say that, Uh, the weapons still support Goddard's
Speaker 1: findings even years later. So the technology we're using now
Speaker 1: suggest that those weapons were the ones used. Yeah. The
Speaker 1: that Bureau of Forensic Ballistics was formed in in April
Speaker 1: nineteen five in New York City, and the whole purpose
Speaker 1: behind it was that by you remember, back in eighteen
Speaker 1: thirty five was the first time we see someone trying
Speaker 1: to identify a firearm, uh, after a crime has happened
Speaker 1: the firearm itself was the one that was used by NIVE.
Speaker 1: There had been a lot of pioneers who worked on
Speaker 1: this idea of identifying firearms based upon the projectiles they fired.
Speaker 1: And uh, the problem was that the the resources were scattered, right.
Speaker 1: I mean, you had you had some communities that might
Speaker 1: have an expert that resides within that community, but then
Speaker 1: you know, you might have hundreds of miles of of
Speaker 1: area where there is no expert, there's no one to
Speaker 1: call upon. And so the Bureau was formed as a
Speaker 1: resource for law enforcement agencies across the United States. There
Speaker 1: were other countries that were doing similar things. Actually, a
Speaker 1: lot of this early research where the idea was, hey, look,
Speaker 1: they are these markings on this bullet. They're consistent with
Speaker 1: every bullet that's fired from this particular gun, and they're
Speaker 1: different from all the ones that are fired from that gun.
Speaker 1: That kind of work was being done all over the world.
Speaker 1: In fact, there were a lot of people in France
Speaker 1: who wrote a lot of instrumental early papers on identifying
Speaker 1: firearms based upon their projectiles or Yeah, and then to
Speaker 1: the FBI. The Federal Bureau of Investigation here in the
Speaker 1: United States was directed by a their jaunty head of
Speaker 1: staff Jagger Hoover. Yes, I think that's the first time
Speaker 1: I've ever heard is I think that's what Jay stands for, right,
Speaker 1: John T. Edgar Hoover, Um, No, not at all. Uh
Speaker 1: he know. I was more like really said that elite.
Speaker 1: Uh So it was a question mark, like the sarcastic kind.
Speaker 1: It wasn't actually an interrobang, gotcha. So he directed that
Speaker 1: the FBI should create a lab for ballistics forensics as well,
Speaker 1: and so this was becoming really serious business, and there
Speaker 1: were there were a lot of early cases between you know,
Speaker 1: the late eighteen hundreds and and nineteen twenty that established
Speaker 1: that this was a legitimate means of investigation. So let's
Speaker 1: talk a little bit more about what you actually do
Speaker 1: when you're trying to identify whether or not a particular
Speaker 1: bullet was fired from a particular gun. First of all,
Speaker 1: it helps if we if we talk about bullets and cartridges,
Speaker 1: because we and we've done this in another podcast, but
Speaker 1: it always helps because a lot of I think people
Speaker 1: who are generally unfamiliar with guns don't know the anatomy
Speaker 1: of a gun. Yep. And that's part of why I
Speaker 1: wanted to mention that about the muskets um because you know,
Speaker 1: after a while they realized that the system that we're
Speaker 1: about to talk about, it makes the weapons much more
Speaker 1: reliable using those things, and faster to operate because rather
Speaker 1: than having to put the powder in the in the
Speaker 1: wadding and all that stuff in there and and prepare
Speaker 1: the weapon to be fired. I mean, I saw I
Speaker 1: can't even remember what show it was. I saw a
Speaker 1: thing on TV where they had somebody firing and must
Speaker 1: get as fast as they could, just to see how
Speaker 1: quickly a trained um musketeer could fire a weapon. It's
Speaker 1: about three times per minute. Three times per minute is
Speaker 1: considered an excellent time fast. Yeah, I know, I've seen
Speaker 1: I've seen artillery cruise that we're using, uh period cannon's
Speaker 1: um actually wasn't a cannon, but anyway, it was. It
Speaker 1: was an artillery gun, period artillery gun. And they talked
Speaker 1: about how even with a well trained group of troops
Speaker 1: who were familiar with the weapon, three times a minute
Speaker 1: was considered to be the peak performance. So one of
Speaker 1: the biggest innovations was the idea of why don't we
Speaker 1: take the system of gunpowder and wadding and shot and
Speaker 1: all that, and why don't we try and figure out
Speaker 1: a way of packaging it all into one thing that
Speaker 1: you load into a gun once and then you fire.
Speaker 1: So instead of having to load in all these separate
Speaker 1: pieces and pack them together and hope that it fires correctly,
Speaker 1: it's all packaged together. And that's the idea behind the cartridge.
Speaker 1: In fact, the earliest cartridges were these little paper cartridges
Speaker 1: that had everything packed together, and uh, they were used
Speaker 1: in the Civil War mainly, but then actually that was
Speaker 1: sort of the step between where you put the cartridge
Speaker 1: in and then and then the musket ball right right,
Speaker 1: the shot. Yeah, the cartridge contained essentially all the stuff
Speaker 1: that you would have put in previously besides the shot itself. Well,
Speaker 1: the modern day cartridges have the the fuel that's going
Speaker 1: to push the the bullet forward, and the bullet itself
Speaker 1: all packed together. So you've got a case that's typically
Speaker 1: made out of something like brass or maybe steel, depends
Speaker 1: on the particular manufacturer, and the ammunition involved a typically brass,
Speaker 1: and then you have a bullet at the end. The
Speaker 1: bullet is the actual projectile that will fire out the gun.
Speaker 1: The case remains behind. Now, the case also contains it
Speaker 1: contains powder, primer and a primer mix and uh, and
Speaker 1: that's the stuff that when a firing pin from the
Speaker 1: weapon hits the primer, that ignites the primer, which then
Speaker 1: in turn ignites the powder which creates this massive amount
Speaker 1: of gas. Massive and a relative term, I should say,
Speaker 1: um amount of gas within the case. That's what pushes
Speaker 1: that that bullet out of the weapon. So the case
Speaker 1: remains behind. The case is actually altered by this because
Speaker 1: the gases are pretty hot. Then they pushed pretty hard,
Speaker 1: so the case itself will change a little bit. Then
Speaker 1: you have to extract the case from the weapon and
Speaker 1: put a new cartridge in its place in the chamber
Speaker 1: of the weapon in order to fire it again. And
Speaker 1: of course we've also talked about machine guns. Uh, if
Speaker 1: you're talking about an automatic weapon, you put in you
Speaker 1: have a magazine feeding mechanism, feeding mechanism that will automatically
Speaker 1: pop the next it will pop the spent cartridge out
Speaker 1: of the weapon, and uh, load the next cartridge in
Speaker 1: and ready to be fired. And it happens very very quickly.
Speaker 1: So but it operates on the same same principle. So
Speaker 1: here's the interesting thing, A couple of interesting things. First
Speaker 1: of all, we talked about the rifling with the grooves
Speaker 1: within the barrel which are going to cut into the bullet,
Speaker 1: making a fingerprint on that bullet, so that if you
Speaker 1: were to find two bullets fired by the same gun
Speaker 1: and you were to compare them side by side, you
Speaker 1: should be able to see the same markings on both
Speaker 1: because it's it's going to carve it out the same way. Well,
Speaker 1: the same sort of thing goes plays for the cartridge
Speaker 1: or like the case, rather for the cartridge. Um, the case,
Speaker 1: the spent cartridge is going to have some markings on
Speaker 1: it as well. Um, some of it may be matches
Speaker 1: just from you know, the way that it sits in
Speaker 1: the chamber, or if there if there's an extractor, if
Speaker 1: there's an actual mechanical element in there that kicks that
Speaker 1: spent cartridge out, that can leave a mark on the
Speaker 1: case as well. So that way, if you don't maybe
Speaker 1: you don't even have the bullets, maybe you just have
Speaker 1: to spent cases, you can compare those and see. So
Speaker 1: I stepped one of identifying the weapon is identifying what
Speaker 1: caliber of bullet was used, and you know what kind
Speaker 1: of cartridge was used, because that will limit the type
Speaker 1: of weapons that could have fired that particular ammo, right,
Speaker 1: because not every gun fires every immunition. Because anyone who
Speaker 1: has ever worked with guns nose are very specific kinds
Speaker 1: of ammo that work with particular guns, and you cannot
Speaker 1: you cannot interchange them. Chris and I have more to
Speaker 1: say about ballistics and forensics science, but first let's take
Speaker 1: a quick break to thank our sponsor. Each weapon. Now,
Speaker 1: each manufacturer when they make when they put the grooves
Speaker 1: in there and the the section between UM. Basically the
Speaker 1: ridges around the grooves are called lands. UM. Those metal
Speaker 1: ridges basically are what helped the bullet reach its destination
Speaker 1: by providing it the spin and accuracy UM. But they
Speaker 1: also are are common to manufacturers. So one weapons manufacturer
Speaker 1: might put six grooves in the barrel, one might use four. UM.
Speaker 1: So one of the things these marks left and they
Speaker 1: are unique to every weapon. UM. These marks are going
Speaker 1: to help the forensics investigator if if if they can
Speaker 1: find the bullets, they're going to be able to identify
Speaker 1: which manufacturer made the gun. That will help track it
Speaker 1: down and then from there they can look at other
Speaker 1: things that will help them at least narrow down and say, well,
Speaker 1: this couldn't have been Uh, this couldn't have been the
Speaker 1: gun that fired it because it's not even the same manufacturer.
Speaker 1: It's not the right people. So we can rule this
Speaker 1: out because there they can look at specific guns, because
Speaker 1: multiple manufacturers can make the same type of gun. Yes,
Speaker 1: so yeah, so narrowing it down to your first you
Speaker 1: look at the caliber of the bullet, uh, and the
Speaker 1: case so that you can determine what kind of ammo
Speaker 1: was used. That narrows it down to a range of
Speaker 1: weapons that might be able to fire that. Looking at
Speaker 1: the actual patterns on the bullet itself and well, we'll
Speaker 1: give you at least an idea of of the specific
Speaker 1: type of weapon used and the manufacturer. And then again
Speaker 1: comparing that bullet with one like a test bullet fired
Speaker 1: from a weapon. We'll let you know if it's fired
Speaker 1: from the same weapon. So you're you keep narrowing it down.
Speaker 1: This is very scientific. I mean you're talking about going
Speaker 1: from the general to the very specific. So you're just
Speaker 1: eliminating all the other options until what you're left with
Speaker 1: is the only, hopefully the only uh possible answer. And um,
Speaker 1: there are a lot of different ways that that these
Speaker 1: the cartridges can have marks on Besides the ejection UM mark,
Speaker 1: there can be firing pen marks, so you can see
Speaker 1: how the firing pin struck the bottom of the cartridge.
Speaker 1: That will tell you a lot about the type of weapon.
Speaker 1: Like there's certain weapons that have a very distinct firing
Speaker 1: pen mark, so like a square, one's good indicator that
Speaker 1: was a glock that fired the weapon. And there are
Speaker 1: certain marks that are you're going to find that are
Speaker 1: common to particular types of weapons. So forensics experts will
Speaker 1: use that when they're actually examining UM bullets. So let's
Speaker 1: let's say there's a there's a crime case. Let's make
Speaker 1: this more specific. There's a crime case in which someone
Speaker 1: was shot UM and the police have recovered a weapon
Speaker 1: from a suspect. They do not know if the weapon
Speaker 1: is the one that was used used in the crime.
Speaker 1: They do know that it matches the same UM model
Speaker 1: and maker of the weapon that was used in the crime.
Speaker 1: But that's all I know. The forensics expert what they
Speaker 1: will do is they'll take the gun UM. They'll take
Speaker 1: possession of the gun that's from the suspect, and they'll
Speaker 1: fire it into a water tank. And the water tank
Speaker 1: is a long tank of water several, and it's usually
Speaker 1: around ten feet long. It's got about three ft wide
Speaker 1: three ft high full of water and on one end
Speaker 1: of this water tank which is sealed on all sides,
Speaker 1: which is important you don't want any stray bullets flying out.
Speaker 1: There's a a hole through one side, a tube where
Speaker 1: you can fire. Through that tube, it goes into the water.
Speaker 1: The water is meant to slow down the progress of
Speaker 1: the bullet, and as it slows down, it'll come to
Speaker 1: arrest at the bottom of the tank. You the forensics
Speaker 1: expert will retrieve that bullet and then they take that
Speaker 1: bullet and the bullet used in the crime, assuming they've
Speaker 1: recovered a bullet, because otherwise there's no point in doing this.
Speaker 1: So they've recovered a bullet from the crime itself. You
Speaker 1: put that and the test bullet or several test bullets
Speaker 1: into a macroscope, a comparison macroscope, and you might think, hey, Jonathan,
Speaker 1: what's a macroscope. I've heard of microscopes. Well, macroscope is
Speaker 1: it's it's a device that does magnify things, but it
Speaker 1: usually magnifies them by a pretty small multiplier compared to
Speaker 1: a microscope. You know, microscopes you're talking about multiplying magnifying
Speaker 1: something by a hundred times or more. Macroscopes tend to
Speaker 1: be five, ten, maybe twenty times, so it's not it's
Speaker 1: not giving you that incredibly up close look that a
Speaker 1: microscope would. It's called a comparison macroscope because you can
Speaker 1: actually put in two different items. So in this case,
Speaker 1: you put the bullet from the crime and the bullet
Speaker 1: from the test, uh onto the little platform it actually
Speaker 1: and here's there with some sticky stuff some some you know,
Speaker 1: it's essentially glue um, and then you put it through
Speaker 1: the microscope. The microscope directs the images up to the
Speaker 1: viewfinder where you look in and you can actually see
Speaker 1: side by side the two projectiles, so it looks like
Speaker 1: it looks like they are, you know, right next to
Speaker 1: each other, even though they're actually on two different little
Speaker 1: platforms on the macroscope itself, and it allows you to
Speaker 1: take a really close look and compare those markings at
Speaker 1: a a nice magnified level to determine whether or not
Speaker 1: they are identical, or whether or not the markings are identical. Obviously,
Speaker 1: the bullets can't be yeah, because someone is probably saying yeah,
Speaker 1: but Jonathan, why do they have to fire it into
Speaker 1: a water tank. I mean, why couldn't they just you know, uh,
Speaker 1: go to the crime scene and shoot it off the
Speaker 1: wall and see what happens. Well for one thing, of course,
Speaker 1: again you don't want stray bullets. But um, you know,
Speaker 1: I don't know if any if a lot of people
Speaker 1: know that. I mean, it probably is common sense when
Speaker 1: you think about it. But bullets the form quite a
Speaker 1: bit in the process of firing them. Um. Actually, I
Speaker 1: remember my rifle recourse at camp when I was a kid. Um.
Speaker 1: Every once in a while, Uh, the instructor would take
Speaker 1: us down to the end of the range and there
Speaker 1: was a big pile of dirt there. So the bullets
Speaker 1: would go through the targets and hit the dirt and
Speaker 1: stopped there. So we would go in and dig some
Speaker 1: of them out and they would come out in the
Speaker 1: oddest shapes. The thing is, um, you want the bullet
Speaker 1: to be identifiable enough so that you can really see
Speaker 1: the markings on it. Um, and shooting it against something
Speaker 1: else that will catch it. Uh, you know, it will
Speaker 1: also be deformed by the impact if the water slows
Speaker 1: it down and it basically just drops to the bottom
Speaker 1: of the tank. Once it this forward momentum stops, um,
Speaker 1: then it's going to be much less affected by the
Speaker 1: impact of of uh its landing and um, then you
Speaker 1: can get a good idea of what is actually going
Speaker 1: to look like in the marks that are on it.
Speaker 1: And and sometimes the bullets retrieved from crime scenes are
Speaker 1: in really bad shape, I mean, because they've they've gone
Speaker 1: through various materials, especially if you know they maybe hit
Speaker 1: like a door frame or something or you know whatever. Uh,
Speaker 1: And it can be a challenge to identify them just
Speaker 1: because the bullets themselves may not be indecent enough shape
Speaker 1: for you to be able to make a good comparison.
Speaker 1: But this is to try and make the the conditions
Speaker 1: as ideal as possible so that you can at least
Speaker 1: narrow things down. You know, the goal really is to
Speaker 1: see if you can eliminate that gun from suspicion, because
Speaker 1: if you can, then you know you're on the wrong
Speaker 1: track and you can go direct your attention elsewhere and
Speaker 1: not waste time on something that ultimately is a dead end.
Speaker 1: So UM, yeah, I mean that's that's your basic approach.
Speaker 1: It's kind of interesting, like the whole process of developing this,
Speaker 1: I mean, there were there were earlier uh forensics experts
Speaker 1: who would compare bullets. They didn't have the luxury of
Speaker 1: a comparison macroscope to use, so in many cases they
Speaker 1: were using photography. They would take um pictures of these
Speaker 1: bullets and try and enlarge the photographs as large as
Speaker 1: they could and compare them that way, and try and
Speaker 1: find as many points of comparison as they could between
Speaker 1: the two to determine whether or not a bullet was
Speaker 1: in fact fired by the same weapon as another bullet.
Speaker 1: So again, points of comparison, just like with fingerprints, you know,
Speaker 1: you look for a certain number, and if you figure
Speaker 1: that if you find now uh like a dozen or
Speaker 1: two dozen points of comparison that are identical, the chances
Speaker 1: of that being just coincidence are pretty slim. So that's
Speaker 1: when you sit there and say, no, I'm pretty sure
Speaker 1: this bullet was fired by the same gun as the
Speaker 1: one that I tested. We've got a bit more to
Speaker 1: say about ballistics, but before we do, let's take aim
Speaker 1: at a commercial break and another thing that that Goddard
Speaker 1: did along with his partner um back in the very
Speaker 1: early days of all this, he started they started compiling
Speaker 1: a database of information about different weapons UM, which is,
Speaker 1: if you think about it, rather crucial uh to doing
Speaker 1: this because it allows you to know, you know, in
Speaker 1: which direction and which angle a particular manufacturers uh lands
Speaker 1: are going to show up inside the barrel. UM helps
Speaker 1: you eliminate you know, they can look at a bullet
Speaker 1: and go, oh, well, I know that it's not this
Speaker 1: or this or this or this, And by the scientific method,
Speaker 1: I've at least narrowed it down to one manufacturer and
Speaker 1: from there, you know, and and having all that information
Speaker 1: in a database and comparing the weapons uh and I'm sorry,
Speaker 1: the bullets side by side, it gives you, um the
Speaker 1: ability to scientifically rule things out step by step. And
Speaker 1: he really created a method and a plan for doing
Speaker 1: this that set the stage for what we know as
Speaker 1: modern ballistics work. Yeah. And it's if you read about again,
Speaker 1: I do urge you to check out more information about
Speaker 1: the progression of of keep gathering this information because it
Speaker 1: goes beyond just comparing bullets to each other. The history
Speaker 1: of forensics is pretty fascinating and in some ways sometimes
Speaker 1: darkly humorous and in some cases just bizarre. Like you'll
Speaker 1: you'll find out about people sheriffs who found a victim
Speaker 1: who had um a hole in their shirt and there
Speaker 1: was suspicion that perhaps a a gun had you know,
Speaker 1: the person had been shot by a gun and that
Speaker 1: a bullet had toward the whole. So the sheriff would
Speaker 1: take the shirt out to a firing range and fire
Speaker 1: bullets into it to see if the tears that were
Speaker 1: made by the bullets were similar to the one that
Speaker 1: was on the shirt in the first place. Well, they
Speaker 1: can tell, um whether a wound is an entrance wound
Speaker 1: or an exit wound some by the the type of
Speaker 1: hole that it leaves. I mean, if you're um right
Speaker 1: on top of somebody, uh, it will um do more damage.
Speaker 1: If you're firing at somebody at point blank range, um,
Speaker 1: then if you are farther away. But you can tell
Speaker 1: by the direction of the fabric, you know, if it
Speaker 1: if it's going into the wound, then you could see
Speaker 1: generally that it's probably an entrance wound. And if the
Speaker 1: fibers are are spreading outward, then it's probably. And it
Speaker 1: depends on the bullet too, of course, there are bullets
Speaker 1: that do a lot more damage on on one side
Speaker 1: or another, so that that factors into it. Too. Of
Speaker 1: course they'll talk about things like blood spatter. Um, I
Speaker 1: have a great story here. I want to want to
Speaker 1: tell them so alright. So in uh, in nineteen o three,
Speaker 1: a fellow named E. J. Churchill in London, England provided testimony,
Speaker 1: uh do testimony that regards an experiment he had performed
Speaker 1: that involved shooting bullets into sheep's skulls. Yeah, so skulls
Speaker 1: of sheep, not actual sheep at this point that the
Speaker 1: sheep have already shuffled off the wooly mortal coil and
Speaker 1: their skulls have remained. And what had happened was, um,
Speaker 1: it was all revolving around a case where there was
Speaker 1: a young woman who or a woman I don't know
Speaker 1: if she was young, actually a woman who was shot
Speaker 1: and killed in Essex, England. And uh they figured that
Speaker 1: she had been shot by a thirty two caliber revolver,
Speaker 1: And so Churchill took a similar revolver with the same
Speaker 1: sort of ammunition and a whole bunch of sheep skulls
Speaker 1: and started shooting the sheep skulls at various distances to
Speaker 1: determine to kind of compare the damage done, to see
Speaker 1: how far away the shooter might have been from the
Speaker 1: victim by observing, you know, the damage done to the
Speaker 1: sheep skulls, and he came to the conclusion that the
Speaker 1: the revolver was shot somewhere between six and twelve inches
Speaker 1: away from the victim, and this was used. This testimony
Speaker 1: was used in the court case. In fact, the the
Speaker 1: accute suspect was found guilty and put to death. So
Speaker 1: the experiments early on were very practical, you know, the
Speaker 1: idea of we have this one set of circumstances, we
Speaker 1: need to try and recreate it as closely as possible
Speaker 1: to to determine whether or not the scenario we have
Speaker 1: in our mind is actually at all accurate. And uh,
Speaker 1: and you know, like I said, the history of forensics
Speaker 1: is filled with stories that make that one seem tame
Speaker 1: and boring in comparison. Well, and and there are others
Speaker 1: that are oddly similar, um, that make you realize that
Speaker 1: it isn't always exact. Because um, Ramslin mentioned a case
Speaker 1: that happened in Oklahoma where a robber used a seven
Speaker 1: magnum and uh, there was a witness and he shot
Speaker 1: her right in the head. I'm just sorry, um. And
Speaker 1: uh what happened was the bullet went into her skull,
Speaker 1: but it traveled around the inside of her skull before leaving,
Speaker 1: and she ended up surviving and testifying against the robber.
Speaker 1: And then another case, uh, somebody got shot in the
Speaker 1: wrist with a twenty two, which is a much smaller
Speaker 1: caliber bullet um and the bullet went into a vein,
Speaker 1: traveled into the heart and killed the person. Bullets don't
Speaker 1: always do well. And I also think I've even heard
Speaker 1: of people getting shot in the head and the bullet
Speaker 1: hits the skull and doesn't penetrate the skull, but rather
Speaker 1: goes underneath the skin, travels around the skull, and pops
Speaker 1: out the other side without actually penetrating the skull itself.
Speaker 1: I remember, I distinctly remember when I was living in
Speaker 1: North Carolina, a police dog getting shot in the head
Speaker 1: and that happening. It's yeah, uh yeah, this is getting
Speaker 1: really much more gruesome than I had intended. You don't mean,
Speaker 1: I don't mean for it to be gruesome, but I
Speaker 1: think it's a situation. Well, I mean, the dog, the
Speaker 1: dog lives. Um, it's a it's a situation that shows
Speaker 1: you that, you know, we sort of assume that if
Speaker 1: you get shot, if you get shot in the right
Speaker 1: place and at the bright distance that you know, there
Speaker 1: are very few chances that you're gonna make it if
Speaker 1: somebody's doing what they're supposed to be or what they
Speaker 1: intend to do, let's say, with the weapon. Um. But
Speaker 1: bullets don't always behave themselves, which is why these ballistic
Speaker 1: forensics are so important because they you know, they've gotten
Speaker 1: it down to a science, so at least you have
Speaker 1: a better idea of what's going on. And we should
Speaker 1: also point out that stuff that this you know, we've
Speaker 1: been talking a lot about bullets. The story is completely
Speaker 1: different if you were to talk about things like shotguns.
Speaker 1: They do not have the rifled barrels, so I mean
Speaker 1: you're firing shot at that point, not not lots of
Speaker 1: little balls. Usually occasionally you might have a slug, you
Speaker 1: could do a shot slug, but at any rate, yeah,
Speaker 1: taser's yeah, totally different story there. But in those cases
Speaker 1: it's that you have to look for different things. You
Speaker 1: can't you know, obviously you can't compare bullets like you
Speaker 1: could with rifled weapons. UM. And in fact, Scott Doyle
Speaker 1: on his site rights it should be noted that not
Speaker 1: all firearms leave consistent, reproducible marks. But overall, it has
Speaker 1: been my experience that around eighty percent of the firearms
Speaker 1: that I examined produce what is sometimes called a mechanical
Speaker 1: fingerprint on the bullets and cartridge cases that pass through them.
Speaker 1: So it is possible even for you to get a
Speaker 1: gun that, through some reason or another, uh, the marks
Speaker 1: that come out, they end up on the bullets the
Speaker 1: cartridges are not I'm not reproducible, and it could just
Speaker 1: be that there's, you know, uh, some sort of weird
Speaker 1: faulty part of that gun. You know, it's there's a
Speaker 1: lot of different factors that could that could cause that.
Speaker 1: And in those cases, of course, then you can't you know,
Speaker 1: the ballistics evidence, as far as comparing bullets to each other,
Speaker 1: is no longer really reliable. You have to rely on
Speaker 1: other kinds of evidence in in that uh, in that
Speaker 1: sort of case, I would be interesting to know if
Speaker 1: any UH law enforcement authorities who have worked with forensics
Speaker 1: and ballistics have are listening to our show, you know,
Speaker 1: so please let us know if you you are, because
Speaker 1: this is interesting stuff, and thank you for the work
Speaker 1: that you do because it makes a difference. And that
Speaker 1: concludes this classic episode of tech Stuff. I hope you
Speaker 1: guys enjoyed it. It's always interesting to go back and
Speaker 1: take a listen to these old episodes, some of which
Speaker 1: in the upcoming weeks are going to be quaint because
Speaker 1: we recorded them so many years ago and so much
Speaker 1: has changed in that time. But I hope you join
Speaker 1: me for those I very much enjoy revisiting them. If
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