The Story of the Gatling Gun

This listener mail comes from Damon, and Damon says, could you please do a podcast on how the Gatling gun works? Because I saw it on MythBusters and I was wondering how it works. Well, Damon, we're gonna talk a bit about the Gatling gun today. It's an interesting piece of technology. But to really understand how the Gatling gun works, we need to go back further and talk about just the

principles of firearms and how they work in general. Here we actually have already touched on a very very early firearm, uh, the arc Bus. Yeah. We talked in our our tech of fifteen hundred. We we kind of went into this. It was technically, you're right, the tech of fifteen ten and uh So going back to around the mid of the fourteenth century, that's when we first started seeing uh not we personally, I wasn't around back then, don't know about you. Put but the that's when cannons first started

to hit the scene in medieval Europe. Yes, but they were they were very inaccurated, so they missed the scene part of the time. I couldn't have the broadside of a barn. But yeah, the the cannon was the probably

the earliest form of gun. Um. I would imagine it probably was simply because they wanted something that would created, uh, something that would fire a big projectile and a gun that that actually is a good point and a gun in this definition is basically a tube sealed off at one end um that that can fire or some sort of projectile. Yeah, and it has at least the early cannon. The way they worked as they had a whole drilled toward the sealed end where you could place a lit

fuse to light the gunpowder. So you would the way you would load a cannon as you would pack the gunpowder into the end of the cannon. Then you would load the shot into the cannon, sometimes with a either uh either with some sort of cloth wrapped around the shot, or you'd actually stuff watting down there to to seal it. Really well, you put the shot in, you put a lit fuse into the hole that lights the gunpowder. The

gunpowder ignites, and essentially it explodes. It burns so quickly that that it we have to call it an explosion. The the gases that are given off when the gunpowder explodes propel the shot out of the cannon. That's where you get the the force you need to blow something up. And the the arquebus uh and other similar weapons like that, other cannon like that. Um, those were known as as the at least the ones that Jonathan is describing here are known as matchlock. The lock is the mechanism that

is used to ignite the powder in this case. So, um, it's basically a very tiny hole and people would stick a um uh, some kind of fuse. It's really often a piece of string would burn down into I mean, you could also stick a match down in there, but you know, it's very very difficulty that there were a lot of problems with it because it's not something you can do in the in the rain. Yeah, yeah, there are actually a lot of problems. So so let's talk about some of the early guns. The early guns were

essentially like handguns. The earliest guns were really nothing more than that tube that you would hold, and it usually took two people to fire one of these. One person would hold and aim the gun, the other person would stick the lit match or lit fuse into the hole to light the gunpowder, and then you would fire it off.

Eventually you got to the point of having handguns. And again it was still really hard to both aim and fire this thing at the same time because you know, holding a lit match and then getting your target in view and then putting the lit match to the whole that's pretty tough. So the matchlock was a huge benefit, right, There was a big leap forward. Yeah, yeah, and then I mean the bigger leap forward being the flintlock. Right.

So the matchlock, what it would do is you would have usually a little a little pan that would hold some gunpowder and you would pull a trigger the the lit fuse would be on the end of a lever. Pulling the trigger would lower the lever to the pan. It would light that gunpowder, which would go into the breach of the of the gun, lighting the main charge. Right, okay, But as Poulette was saying, if it's raining well and you've got powder exposed in that little pan, you may

not have your on fire at all. And also you had to continuously make sure that your your match was stayed lit. And at night you would have problems because you would be visible because you had this little bit match. The flintlock was a big advantage over the matchlock. Yes, yes, I can imagine now people going, huh, it's an awful lot of fireflies out there tonight, right, might might want to aim at those big guys. Ye. So, so the flintlock had a hammer which was the the the section

of the gun that would hold the flint. You'd have a piece of flint that would be wedged in on the hammer um and the hammer was activated by a tumbler that was connected to a spring. When you cocked the hammer back, uh you could. They had three three

different positions uncocked, half cocked, and fully cocked. So when you say go off half cocked, that's that's where this comes from, which is kind of ironic because you would want it half cocked to load it, and that was the one place well between half and fully when it's half cocked, it can't actually fire. It's right. You would pull the trigger and there's a little lever that would that was up against the tumbler. Right, So the tumbler

has notches in it, and the half cocked notch. This notch is so large that when you pull the trigger, it wouldn't clear the tumbler, so it would not it would not make the hammer. Uh, they would not release the hammer, So there was no way you could accidentally. Theoretically, if the gun was in good shape, there's no way you could accidentally fire it prematurely. Now, when it was fully cocked, then it would be in a slightly shallower notch. You pull the trigger, it releases the tumbler, which is

under tension from a spring. The hammer flies forward and the flint strikes a steel plate and that creates sparks which then light the gunpowder inside again a little gunpowder pan which usually had a cover over it, So you could theoretically fire a flintlock in the rain and still have a good chance of it going off, and again gunpowder lit in the pan would go into the breach of the gun, firing off the main charge. Yeah, the

little piece of metal is known as the frizzen. Yes, um, and the frizen spring is what makes the flint lock weather proof because um, it's what's got the cover that's attached to the frozen over the pan. So it's it's basically due to the design. It's covering the pan where the powder is right exactly. That helps. That helps right there. So what happens is when the flint hits the frizzen.

This sounds really weird, right, when the flint hits the frizzen, it actually lifts the pan, the lid of the pan up. The force of the blow lifts the lid of the pan up, the sparks hit the gunpowder and the gun fires. And then as soon as the gun has is uncocked the pan after after the initial impact, because the spring of the that's attached to the frizen is under tension, it will pull the lid back down. So again you would have to half cock the flint lock in order

to load it again. You would actually load it by putting gunpowder directly into the breach of the gun, but you would have to put a little bit of gunpowder in the the frizzen pan for it to work. Otherwise you just you know, the sparks would not make it to the main charge. So this sets the stage for the next huge leap forward in firearm technology, which was

the percussion cap. Yes, the percussion cap was a tiny little device that was actually it was essentially a chemical compound, uh And it was mercury fulminate combination mercury, nitric acid, and alcohol. And it is very shock sensitive, which means if you hit it, it blows up there. So you what the earliest percussive cap, percussion cap guns had a

little uh, well they called it a nipple. It's a little protrusion that you would put the cap on and you would cock the gun back, just like a flint lock. And the it had a hammer that when you pull the trigger, the hammer would come down hit the percussion cap, which would cause the initial explosion that again lit the charge inside the gun. Right, what really really brought warfare to a new level was when we figured out how to put the percussion cap, the charge, and the bullet

all together in a single cartridge. Yes, and initially I believe people were experimenting with paper cartridges, but they weren't as as refined as when they developed the metal cartridge, which is what we are still using now. You see that, uh, you know, if you look at what most people think of as a bullet, I would say the majority of what most people see is the brass cartridge, which is the bottom part of the bullet. It's the part where the uh, the firing pin strikes and uh launches the

projectile from the gun. Yeah. Yeah, that's the Whenever I think of bullet, I'm thinking of the full cartridge. I'm not thinking of the tip. Now, hunters and soldiers, of course they're going to they have a much better knowledge of the source of stuff. But I think for the layman, when we say bullet, you're thinking of the thing you put in the gun, which technically is a cartridge. Um, and yeah, it has three sections. There's the primer, which

is the percussion cap. There's the propellant, which is the gunpowder or other propellant. And then you have the bullet, which is the tip that that actually fires out of the gun and hits your target or whatever whatever the gun happens. We pointed at. Actually, so in this case, the big change here was that guns now had a firing pen that would strike the percussion cap, so that that's what would ignite the propellant and push the bullet out of the gun, which meant that you had a

spent cartridge in your gun afterward. So, um, I'm sorry, it looks like you're just about to say something, so I'm gonna have shut up. Well, there there's something that we also need to address to, which is the barrel, yes of the gun. Now, I mean, up until this point to roughly, I'm not being exact here, we've been sort of talking about, for the most part, muzzle loading

weapons where you actually put the bullet. Uh and in this case, in the earlier weapons, we were speaking of a lead ball in your bullet, so or you know, a shot in a cannon or a different you know, grape shot or whatever it is that you're firing out it. So let's say projectile. So you're pushing the projectile down the tube and you know, loading it yourself by hand

up until we got to the cartridge point. But um, the thing is in order to make that, well, not in order to make that For the most part, when they started out, there were smooth what they call smooth bore, which means it was you know, the insides of it were smooth, they were polished, and it was easy to push a bullet down there. Well, they also figured out, uh, you know, probably around um I believe that the fifteenth century or so, that that's not really the most accurate

way to get a projectile to its target. By rifling the tube the barrel of the gun, you could do a lot more. You can actually uh add some uh some distance, and you can improve accuracy as well. And initially those those weapons were had barrels that were straight, had straight grooves in them, but eventually discovered that a spiral groove would give would improve accuracy and range, makes

it makes the shot spin right. But it's very difficult to muzzle load when you have a spiral groove, right, because it's like little ridges, right, Yes, So it's it's it's like pushing something past a series of ridges. It's not it's not going to load as quickly or smoothly

as a smooth bore rifle or smooth bore barrel. So breech loading sort of takes the uh, that problem out of the way because at that point, when you have a breech loading weapon, then you are you don't have to push the projectile all the way down the muzzle and get what's what's in the barrel out right. With breech loading, you're putting the shot in toward towards your end, the end that doesn't have the deadly part pointed at you. Uh see, I'm not worried about I'm not worried about

looking like an idiot, because I am one. Yeah. No, I know many of the parts of the gun, but I really honestly don't know what you would call I mean talking about the stock and the and the um. But yes, if you've ever fired a breech loading rifle before, you know that there's a handle down there that you used to lift the breech bolt out, you know, and

and pull the cartridge out. You could put a new cartridge in, lock it into place, and then fire the weapon right it loads the bullet or the cartridge we should say, exactly where it needs to be. That's a big that's a good point because that that was one of the things that that gunmakers had to to figure out in order to make to make cartridge firing weapons useful.

I mean, you had to have the percussive percussion cap positioned at the right spot so that the firing pin would hit it at the right point to to make anything happen. Right, So we're at this point, we're right around the eighteen seventies. Okay, So so the flint was that was way back in the fifteen hundreds, and percussion caps started coming out in the early eighteen hundreds, and then by the seventies that's when we're starting to move

to cartridges. There were some cartridge firing weapons during the Civil War, but eighteen seventies was when they were really starting to get perfected. Yeah, we're to the point where we have very efficient weapons, but they fire basically one shot at a time. You have to load the load the gun, fire the gun, pulled the spent cartridge out, and then put a new cartridge and and fire the

gun again. There were a couple of exceptions that were revolvers which could fire between well, depending on the revolver. The one we're mostly familiar with is the six shot revolver six six Yeah, the Old West, So it's these were the ones that had these six cylinders that would rotate as you were firing the gun, so that would put a new cartridge in firing position every time you

pulled the trigger. The way that worked, and it's important to understand this because it kind of plays in with the gatling gun that we're gonna get to in just a second. The way that worked is that when you pulled the trigger, the trigger actually had a pall attached to a p a w L. It's a component of a ratchet. And what that did was it pushed against the revolvers cylinders so that it would turn it one sixth of a turn or however many to move the

cylinder in the right position. It would also, at the same time cock the trigger back. And if you when you pulled it all the way to the end, if it's a if it's an automatic revolver, then the trigger the the the hammer comes forward, hits the firing pen, moves into position, hits the percussion cap, and the bullet fires out of the gun. You still have a spent cartridge inside the cylinder, but a new cylinder will move into place as soon as you start pulling the trigger again.

Some of the early revolvers you actually had to pull the hammer back yourself. You couldn't just pull the trigger and have the hammer come back. You'd have to cock it yourself. And that's what would ratchet the cylinder into position. But it wasn't long before they figured out ways to to make that more closer to an automatic process. Um. So if you have a you would have to remove the spent cartridges out once you've finished firing, put new new cartridges in. So there was no way to make

that a continuous firing method. So it still was it was an improvement over the old fire once, reload once method, but it was still not the weapon of destruction that the Gatlink gun turned into. Yeah. Yeah, Now, before we get to the gat Link gun, which was you know, basically essentially an early machine gun of sorts. Um, there were other attempts over the years, for many many years. In fact, I know you wanted to speak of one very famous inventor who tried to come up with a

way to fire multiple projectiles at once. Yeah. So, I mean, this is not the idea of having multiple projectiles or you know, rapid fire projectiles coming from cannon or or from uh smaller guns. You know, this isn't this isn't new to Mr Gatling. No. No, actually, if you want to really look at some some cool designs, a certain Mr Leonardo da Vinci came up with a pretty clever one. Uh, as far as I know, he never made one of these things, But was a design he created which was

a triangular mount that held eleven cannon to a side. Okay, so each side of the triangle had eleven cannon mounted to it, and the idea was that you would load all thirty three cannon and have them ready to go, and then you would aim it at your enemy. Fire the top eleven. So so the inverted pyramid right, Yes, the point of the triangle is facing downwards. You fire the the eleven on top, rotate, do a third of a rotation, and then fire the next eleven, and then

to a third of the rotate. Shouldn't fire the final eleven. Uh. You could not, of course load the cannon as you were firing them, because you would very rapidly run out of men to load the cannon as they were burnt and blown up. But but the idea was that it would be such a terrible weapon that no enemy would dare attack you. So it was that whole concept of I've got to stick big enough that no one's going to bother me. It wasn't really necessarily meant as a

as an actual weapon of war. But you have. One of the biggest problems of any kind of weapon that would fire several times in a short in a short period is that the barrel gets really hot. And so the early experiments with machine gun type of weapons meant resulting in a lot of barrels overheating, breaking, sometimes exploding because the metal was too weak to contain the explosion of the gunpowder inside it. And so they had to

find a way. Someone had to find the way of creating a gun that would be able to fire rapidly without overheating the barrel. And a couple of different people came up with different ideas of guns with multiple barrels. Yes, yes, actually I was going to mention a different person short, Uh it was a little different if and I had never heard of this person before. His name was James Puckle. Did you run across this I didn't. This fellow, he

was a British fellow. And uh came up with a flintlock weapon in around seventeen eighteen that does resemble the Gatling gun sort of, but it actually looks more alike a a revolver rifle and had you know, and and it was an attempt to do that, but unfortunately, being a flintlock weapon, it was it just really was not very practical. Um, But there was an attempt to do that, you know once once the percussion caps. And I realized too that we left out another invention that was necessity

for making this happen. What's smokeless powder. We talk about that, that's true, but it was an important development in making cartridges because with the earlier versions of gunpowder, uh, it burned irregularly from what I understand, and one smokeless powder was invented, the combustion of the gunpowder was a lot more even and when made cartridge weapons a lot more practical.

Not to mention the fact that if you had any sort of weapon that could fire multiple times in in you know, in a few minutes, uh, you had the very real problem of if you don't have smokeless gunpowder, you can't see what you're shooting at. There's that, yeah, because if you ever see a re enactment where people are using muzzle loaded weapons, you'll notice there's an awful

lot of smoke that comes out of this. Yes, yes, well they they do that, I think, especially for the re enactment value of that so that you can get an idea of what it was like at the time. But however, it is awfully cloudy. Are we now ready to speak of Mr Getling? Sure? So, Richard Jordan's Gatling He comes up with this invention in eighteen sixty two, so this is during the Civil War. He actually, uh he pitched this idea to President Lincoln saying that it

was again a weapon that would help crush the rebellion. Um. So with this weapon, never mind, I was gonna make a Star Wars reference. We're just gonna move on. So anyway, that the Gatling gun, the original Gatlan gun had six barrels, but Gatling guns came in varieties of six to ten barrels, depending upon when, when, which model you're talking about. Right, yeah, Britannica told me, uh what, it didn't tell me anything, right, Um.

From the article in Britannica, it suggested that there were ten initially and used paper cartridges initially and in the early experiments that he was doing with it. Right yeah. We should also point out that that thes these guns weren't really used in the Civil War very much other than in a couple of demonstrations. Uh. They they weren't widely distributed, so the gattling gun really had its first major use worldwide anyway, in World War One. But the

the you also occasionally see him in Great Westerns. But the the idea here is that you have six to ten barrels on this on this rotating shaft, all right, so each barrel has its own spring loaded firing pin, so there's not one firing pin at the at the firing position. There are six to ten. However, many barrels there are, right, but you do have to have something to strike that firing pin. Yeah, well, kind of the

way the well has. The gatling gun has a groove in it, a groove cut in it, so that when you are turning the crank, it is a crank turned gun as well. Yes, it's the original one was hand turned, yes, so it was not an automatic weapon. You would actually turn a crank kind of like if you've ever seen images of the old movie cameras that were hand cranked, same sort of principle. Here, you're and cranking this gun

which is rotating the barrels. As the barrels rotate, the firing pins inside the barrels are actually being compressed because there's a groove that's cut into the the gun itself. The as you turn it, the firing pin gets pushed so that the spring inside the firing pin is under attension. It reaches a point where there's a release, the firing pin fires forward, hits the cartridge, and a gun, A

bullet flies out of the barrel. Okay, yeah, I hadn't seen it exactly that way, but yeah, yeah, it makes sense. I had to. I had to watch several videos to really get a good grip on it. And it's it's actually pretty cool that the way that you would load the gatling gun as you would use a hopper, and a hopper is a container that just holds cartridges and

it's gravity fed. So on one side of the gatling gun, let's say, let's for the argument's sake, we'll say that you're in the firing position, so you're behind the gatland gun, and let's say, for argument's sake, the hoppers on the left side right. So what would happen is when you turn the crank. From your perspective, the gun turns in a clockwise position, so at around i'd say that the nine o'clock position, uh, or maybe even ten o'clock. I

guess ten o'clock position. A cartridge feeds into the barrel. You turn the crank, and as you're turning the crank, that firing pin is moving further back until it reaches twelve o'clock and then it fires. Right, you fire the bullet forward. You keep turning the crank as the barrels move over to say the well, but at least by the six o'clock position, the empty cartridge falls out of the breach, right, so you don't have to take the empty cartridges out. It does it? It just the gravity.

It will do that for you. Gravity loads it and gravity unloads it. Yes, and then you just turn that crank. And really the earliest one I think fired around two hundred rounds per minute, and then they later got up to around three six per minute. Yeah, I did read in uh also again in Britannica that you know, more modern versions of the weapon can fire as many as three thousand rounds per minute, right, But that's using a mechanical system. Trying to do it, Yeah, trying to do

it by hand. You're not going to get that. You know, if you get that fast, then you're probably working on the justice League of America, except you wouldn't need a gun. Well you know, yeah, don't. Hey, you know, I'm just coming up with ideas here, So I'm sorry you were about to say something. No, no, no, I was going to say that that really the next cool uh development and guns, And I'm not going to go much further

pass this because there's really no point. Would be the maximum gun by Hiram Maximum, right, he was the one who invented the first automatic machine gun which could fire five hundred rounds per minute, and I was around, and his big development was that he thought, hey, there's a lot of energy that gets released when you fire a bullet from a cartridge. There's the energy that pushes the bullet out of the barrel of the gun, and and

that's a lot. What if we were to harness that energy in such a way that it would cock the gun for you so that would be ready to fire again. And that was the basis that that set the stage for the automatic machine gun. And there's several different ways to achieve this effect, but that's that's the basis. Yeah, as a matter of fact, that that you know, that's basically a gas operated weapon because the gas basically there's another tube an outlet that helps achieve that effect, and

the majority of machine guns today use that. There's also the blowback and recoil methods. Uh. In the recoil method, both the bolt and the barrel travel together, which is hard for me to imagine. I need to I really need to see that because I know the barrel can travel within the gun, which is it's really confusing to me. When the weapon fires, the bolt goes with the barrel and they recoil together, but the barrel keeps snaps back and the bolt stays put, so it automatically pushes it

with it from what I understand. And then blowback is basically the force of the explosion of the gunpowder UM pushing the bolt back for you, UM, and that forces the spring to compress and it's basically ready to fire again. But it's not as efficient as the gas operated Yeah, the gas operated one actually is a piston. There's a there's an additional piston. If you think about the barrel of the gun, like if you were to look at a cross section of a machine gun, you would have

the barrel of the gun is one big tube. You would have a parallel tube that was slightly smaller that has a piston in it, and at the very end of or near the end of that tube, it would be an opening into the barrel. The gases from the escaping uh gunpowder, the escaping explosion would push the piston back, which cocks the gun. And this happens incredibly fast. I mean we were talking just a second five rounds per

minute being the early one. And yeah, all it takes is just that piston moving back and uh and cocking the gun. Again. It's rate of fire. And you had multiple ways of of loading these guns. There were the hopper systems and the gravity based systems where the cartridges would essentially fall into place, and then later you had things like belt feeding systems and just slips, yeah, which is how many the weapons are loaded now. So it's

they really these developments really made the Gatling gun obsolete. Yeah. Well, I mean once you get to something like the Tommy gun, where you can carry around what is effectively the same as the Gatling gun, it's pretty yeah, game over. And even with the Gatling gun like that helped avoid some of the problems of the earlier machine guns, the ones

about the barrels overheating and becoming too weak. But even with the gatling gun, you had different ways of cooling the barrels down so that they didn't get too hot too quickly, because if you did fire that into a sustained fire for too long, it could weaken the metal enough so that there could be an explosion and your gun could totally fail and uh and possibly injured or kill the operators. So yeah, I hope that that answers

your question. Damon. The gatling gun is pretty, uh, a pretty interesting device, and we actually have an article on how stuff works dot com about how machine guns work. There's an entire section dedicated just to the gatling gun, including an animation that kind of shows this firing pin mechanism. So if you thought that was a little confusing, I recommend you go and you look at that article because

it is very helpful. Yeah, it is nice to see it in action if you're really trying to get an idea of of what we're talking about it as far as the mechanism goes and how it works. Right, So keep those questions coming in, guys, and uh, We're finding a lot of questions coming in through Twitter and Facebook, which is great. Those are really easy for us to keep track of. Email is actually a little trickier just because we get so much mail from so many different sources.

It's also easy to answer the quick thirty second questions forum. Yes, and if we don't know the answer, somebody else will. So if you're on Twitter or on Facebook and you're not already following us, fix that. We're tech Stuff h s W both on Twitter and Facebook and uh and we're building a pretty good community in both. We're actually getting some some cool contributions just from our our listeners where some great conversations are popping up, So please come

join that be part of that. If you do still want to contact us the old fashioned way, you can, that's more than acceptable. Our email address is tech stuff at how stuff works dot com and Chris and I

we'll talk to you again really soon. If you're a tech stuff and be sure to check us out on Twitter text stuff hs wsr handle, and you can also find us on Facebook at Facebook dot com slash tech Stuff h s W. For more on this and thousands of other topics, visit how stuff works dot com and be sure to check out the new tech stuff blob now on the how stuff Works homepage brought to you by the reinvented two thousand twelve Camray. It's ready for you.