Tanks 105: Anatomy of a Modern 120mm Round

[@han6211]

"Meaning... not ert" Truly one of the greatest scholars of our generation

[@ManicEngine]

"it won't ert you"

[@victormiranda9163]

@@ManicEngine just like Ert and Bernie

[@CMDRFandragon]

Yeh, Chieftain has a way with words.

[@nomar5spaulding]

I won't lie. I stopped the video there and sent that clip to my sister.

[@robertsmith4681]

I was fortunate enough to meet that legendary individual once, and I can assure you that he is just as "entertaining" in real life lol

[@danielburgess7785]

"This is a bad thing" A phrase that resonates with anyone who has worn lots of green.

[@mathewritchie]

It sounds kind of omenous.

[@andersjjensen]

Sounds as familiar as "a significant emotional event"....

[@zachsmith1676]

@@andersjjensen pretty sure "This is a bad thing" has a rather high chance of turning into "a significant emotional event" if the turret monster has anything to say about having propellant dumped on him

[@bambam144]

jip, it is indeed. greetings from a ret. heavy infantry guy (8,1cm mortar) füsbat 33

[@billbrockman779]

This would be a good phrase for the AF to insert in weapons loading checklists; for example if a 500 lb bomb is dropped.

[@nightshade4873]

How far Humanity has come, from throwing rocks at one another, to throwing rocks at one another at incredible velocities.

[@Mystickneon]

If it ain't broke....

[@nightshade4873]

@@Mystickneon definitely don't mess with it..

[@NavyVet4955]

He who has the better rock usually wins.

[@stuglenn1112]

Since the beginning of the universe F=MA. Exploiting that simple fact of physics will always be what the game is about.

[@nicktrueman224]

So not far then.

[@ES90344]

I wish Mythbusters was still a thing. I'd love to see them test the damage a sabot petal would do to Pvt. Buster and also see how far a petal can fly.

[@robertsmith4681]

Maybe the folks at drivetanks can hook something up, they did arrange for an AP round to be shot at a ballistic dummy recently ... It was gloriously gory lol

[@genericpersonx333]

I am pretty sure actual people have demonstrated that the danger is quite real, so we can save the budget and focus on the story that one can sit on a helmet with a live grenade under it and be propelled several meters safely.

[@SonsOfLorgar]

The petals have are made of cast aluminium, a 120mm M829 V⁰ is around 1670±15m/s out of a Rheinmetal 120mm/L44 gun. The penetrator is 627mm long and 27mm diameter Knowing the length and diameter of the rod, the diameter of the bore, you can use the observed proportions and profile of the petals to mathematically extrapolate the volume, and thus the mass and air resistance of the petals to calculate their deacceleration/m of travel after separation and thus the impact force they will impart to anything they strike at a given distance of travel from V⁰ at the point of separation. Have fun! 😁

[@NoobLord98]

@@SonsOfLorgar This is pretty much computationally infeasible for any old schmuck at home, considering you're going to have to be doing CFD to calculate exactly how much drag the petals encounter as they leave the barrel, and CFD is really a high performance computing task considering we can't figure out an analytic solution to the Navier-Stokes equations

[@jwenting]

@@NoobLord98 which is why the shapes and sizes of these things were derived to largely by experiment rather than computation.

[@barelyasurvivor1257]

When The Chieftain says "This Is Bad" It is bad! The Chieftain is a master of understatement!

[@ZGryphon]

Firing sabot with the sight set for HEAT, and vice versa, was the bane of my existence in MicroProse _M1 Tank Platoon_ back in the day.

[@klobiforpresident2254]

MicroProse, now there's a name I haven't heard in twenty years. Time to boot up Masters of Orion and scratch an old itch.

[@PlokJeDS]

@@klobiforpresident2254 if you haven't yet, pick up a copy of Highfleet. It's a hoot

[@Trve_Kvlt]

​@klobiforpresident2254 Microprose has made a pretty big comeback in recent years, rereleasing copies of their older games and publishing new ones. If you want a great tank simulator, or rather simlite, check out Gunner, HEAT, PC! It's not published by Microprose, but it's a fantastic game.

[@philchristmas4071]

Never seen a 120mm tank round sitting on a desk. Really gives you a prospective on the size of those rounds.

[@tackytrooper]

It's the reason anything made with a gun larger than a 120 will have to have an autoloader out of necessity...

[@jic1]

@@tackytrooper This is a somewhat pedantic point because I know it's not exactly what you are talking about, but if I don't bring it up somebody else will: the M551 Sheridan had a 152mm main gun and no autoloader.

[@ab5olut3zero95]

@@tackytrooperIIRC 155 artillery rounds are still manually loaded in Paladins.

[@JP-xd6fm]

@@jic1 I know the level of penetration of those rods, and I really can't believe Why is that you don't win a war having such a powerful round, I mean, you can shot at a convoy of pick up trucks from the front and destroy the engine of all of them with one shot. So I wonder, What's wrong?, You can't aim properly with that?, It doesn't fly straight enough?

[@banaana1234]

Good luck trying to line that shot up@@JP-xd6fm

[@edwardstd52]

i still have the 105mm casing that misfired when on a range at Fort Knox. The primer tube didn't have holes on one side, resulting in the propellant not igniting correctly and cracking the side of the casing on the opposite side of where the primer holes were missing. The HEAT-TPT round went about 50 meters down range and it took a while to get the expanded casing out of the breech. Oh, and by the way, the electrical contact that sets off the primer should be on a rubber pad and not touching any part of the vehicle. An M60A3 in a neighboring battalion in Germany had a bad day when one of the battery cables shorted to the hull which then set off all the rounds that didn't have the rubber insulation. In those days (the 1980s) the tanks had all their main gun rounds uploaded. There is a lot more to that gory story, but that's enough for now.

[@felixthecat265]

Sounds more like a heat treatment failure on the case.. missing primer holes could result in poor ballistics, but should not affect the case. The HEAT-TPT charge is fairly small compared with a sabot charge... Traditional cart cases are made by deep drawing which leaves a lot of residual stresses in the metal. The cases need to be annealed by heating them up to remove the stress and soften the metal otherwise it can crack.

[@edwardstd52]

@@felixthecat265 Just relaying what the ammo inspector told me.

[@DanielsPolitics1]

It’s like he said the thing about electrical isolation at 2:42

[@rph111745]

In the 60s there was an incident at the railhead (Can't recall if was Hohenfels or Graf) where one crew put up there radio antenna before clearing the yard, that M60A1 was totaled.

[@edwardstd52]

@@rph111745 Similar situation in the late '70s (If I remember right) where a train that had been loaded with 3AD tanks was getting ready to pull out of the station. A tank crewman had forgotten something in his tank, went back to get it, and touched the overhead powerline for the railroad's electric locomotives. Big flash. Not much left. 😒

[@Chrinik]

I think the weirdest thing about modern tank ammunition is that the silver, shiny case that holds everything together is basically cardboard... The backcap also made for a good ashtray in our barracks.

[@mungo7136]

Rather than cardboard it is celluloid.

[@DrunknBraindead]

It's way weirder that the silver, shiny case is made out of the stuff people used to make photographs with. There is still a flash involved but what changed is the position you want to be at when it occures.

[@balrogthane]

@@DrunknBraindead This flash will give you SERIOUS red-eye.

[@Covah86]

Still got my aft cap. Wasn't a tanker but I was posted to an armoured unit, they let me punch a bomb and keep the cap. Best job I never had.

[@darionapoli4736]

I expected the APFSDS darth to be longer. Still a really interesting, simple yet complete video. :)

[@bluntcabbage6042]

Modern ones are far longer, the one he has is an older dart from a 105mm gun if I recall correctly (might be M735, one of the first APFSDS rounds the US employed).

[@thijshagenbeek8853]

Every other YT channel. Diagrams and pictures. And this bloke just brings a bloody round home to show us. Boss.

[@AbramsGunner]

The M1 slicks 105mm was a lot of fun... hot canisters bouncing around inside the turret with you, and melting your boot laces. The 120's aft caps were a huge improvement, although I hated the folding box monstrosity they designed to catch and contain them. I never had a case come apart, but did on a couple of occasions have the breech block come up on rounds half in and out of a hot tube. That gets your blood pumping pretty good. Thanks for the memories!

[@johanmetreus1268]

8:54 HEAT FOA (Försvarets Forskningsanstalt, don't ask how they got that acronym, but it's the Swedish Defence Research facility) did high-speed x-ray footage among other things to establish what is actually going on in there. The liner should be as malleable as possible, that is the ability to be reshaped without breaking or tearing. The shape is also important, as when the charge detonates, it will geometrically accelerate (if you think of a turntable, the outer rim has to travel a LOT faster than the inner rim for any given rpm due to geometry) somewhere between 20-40% of the disc into a long "needle" that, with a temperature at this point around 600-800°C (so not molten by any means), will travel toward the armour at speeds in the area of 8 000 m/s to 10 000 m/s. Exact percentages and speeds are determined of the shape of the liner, which is why it is a critical design. Even more critical is the diameter, as that gives the base value from which the percentages are calculated so larger diameter = longer needle. The liner NOT turned into a needle is compressed into a carrot shaped lump that trails the needle at in this context insignificant speeds. Impacts at these hyper-velocities leaves the normal material sciences out of the picture. Instead, the analogy best describing the process would be using a high pressure water-hose to blast a hole in a dirt wall, just keeping the muzzle steadily aimed at the same spot until someone turns the valve off after a specific time, which is when you run out of needle. The contact spot between armour and needle as it keeps going deeper is where you get all sorts of heat and plasma nastiness, that upon penetration will spray into the compartment behind the armour, followed by what is left of the directed explosion's pressure wave. Continuing the analogy, we can easily explain some armour effects as well. If rolled steel armour is like uniform soil, ceramics are more like small pebbles. Water will move them without a problem, it just takes more of your total water doing so.... and remember, if you run out of water before the target runs out of dirt armour, you'll fail to penetrate. Explosive reactive armour in this case would be the same as if someone gave you a hard slap on the hand holding the hose muzzle. The water stream would go all over the place until you can steady it again on the hole you want to make. The water will be turned off after the specific time no matter what you do with it, so you just wasted a bunch of it. Passive reactive armour is more like tapping the muzzle. It isn't as effective as the ERA slap, but has the advantage of being repeatable if hit again. Hopefully, least someone found this useful.

[@Bialy_1]

FOA->completly irrelevant from historical point of view as Germans made that research first and they also made the x-rays->as they pionered the common use of shaped charges on the battlefield... "The liner should be as malleable as possible, that is the ability to be reshaped without breaking or tearing." -> another irrelevant information, you should switch your source if FOA is selling this type of missinformation... heh "so not molten by any means" yea, that is why Chieftan is selling complete BS by claiming the jet is "plasma". "The liner NOT turned into a needle is compressed into a carrot shaped lump" the shape of the "needle" depends on the shape of the liner and also the distance from the target=>clearly WW2 era German research was better as they tested it with all that X-ray photos... "is where you get all sorts of heat and plasma nastiness, "-> now you contradicting yourself... heh Your comment is good to test your lack of knowledge in the topic... at the moment it is high! The key thing here is not "heat and plasma" as heat is too low to melt copper not to mention steel and to get plasma out of copper and steel you need idioticaly high temperature and as you were happy to mention the temperatures... -> shows that you did not put to much effort to ad all your informations together. The key factor here is speed... especialy the speed of sound in metals!-> it is too high for this metals to resist to all the forces like a solid matter...

[@BleedingUranium]

The science of HEAT rounds is always fascinating, thanks for this!

[@johanmetreus1268]

@@BleedingUranium Glad you enjoyed it :)

[@denniskrenz2080]

What might be important to say: At those high temperatures just about 150°C below the melting point (at normal pressure), copper behaves more like putty, but is of course physically still a solid. Also, even this needle is forged at supersonic speeds (sonic speed of metal is about 5 times higher than the one in air!), because what is initially in the front travels slower than the following needle parts that experienced more explosion and that really makes the damage: The spike of the projectile is just long enough so that the different needle particles/droplets/whatever-you-like-more arrive on the target at the same time. That is why increasing the distance of the needle to travel to your armour, like by installing metal fences around your tank, is so effective against HEAT.

[@sskuk1095]

Thanks for the contribution! Great analogies!

[@panzerwagen6493]

I've had a couple of aft caps separate. One I was able to kick into the breech and fire. The other one had to be rammed out from the muzzle with the cleaning rod. Super exciting stuff!

[@folgore1]

Neat vid! I was in a National Guard tank unit 1986-94. We started off as 19E's but transitioned to 19K as Desert Storm was kicking off. As one would expect, we were given the "straight" M1 with 105mm gun as the active Army was getting the M1A!. Needless to say, the spent casings took up precious space in the cramped interior of a tank. I can only imagine how bad things would've been in the M1A1 is they hadn't come up with "combustible" casings. Interesting to hear how gentle one had to be with the 120mm rounds as a result.

[@robertsmith4681]

I have often wondered about the specifics of those rounds, only having been exposed to bits of them that had been turned into ashtrays and such, manuals just don't do them justice. Well done Sir, thank you !

[@mooneyes2k478]

First read this as "exploded to bits by them" and was much confused.

[@robertsmith4681]

@@mooneyes2k478 With the stuff you find at gun shows sometimes, well, you never know :P

[@lawrencelaird2919]

Muzzle Brakes/ Sabo = Bad things? Some time back a .50 BMG rifle came apart after firing sabo rounds. The failure was blamed on a buildup of material from the Sabo pettles on the muzzle brake. Thus part of the reason for “not using SABO in weapons with a muzzle break”.

[@mooneyes2k478]

@@lawrencelaird2919 First, "sabot". Second, firearms sabots aren't the same as artillery/tank guns, and they don't have petals.

[@robertsmith4681]

@@lawrencelaird2919 yeah all kinds of wacky rumors came out of experiments with small caliber sabot rounds, more or less has been shown to all be soldiers lore by now. If there is a documented case of a gun getting blown up or damaged, I have not seen it, unless it involves Bubba's p*ssing hot reloads like those Scott from Kentucky Ballistics got hold of ..

[@frankfreeman1444]

Thank you sir for the wonderfull and understandable explanations! I am a Vietnam vet, but in the USAF, and they never let me carry anything in 120mm size, so I am a virtual novice!

[@fearthehoneybadger]

A bullet board made of those things would be heavy as hell.

[@aries144]

Fantastic video! I really enjoy your humor and seeing the practice round and projectiles in a video instead of a picture or drawing, along with your concise and interesting explanation, was very cool. Thank you!

[@classicfrog80]

I really like this format. Hope to see more videos like this.

[@dyoung6425]

When describing the 'jet' of a shaped charge you can use the term 'hyper-tensile-solid'

[@kickthesky]

I remember vacuum loading the rounds in the M60A3, a skill that was not taught in AIT, but once you got to your first unit. It was very difficult for all of us to break that habit when we got the M1A1s in Vilseck back in 1989.

[@MrGeorocks]

Can I ask what vacuum loading is?

[@SheepInACart]

@@MrGeorocks Its the MYTH that by lap loading (see the video) in a tank with a bore extractor you can throw a round into the breech as soon as it opens an have the round sucked inside. Its the sort of thing thats talked about widely in armed forces because it *sounds* like it could work if you've had a basic explanation on what a bore extractor does, but a quick check of the actual pressure curve vs recoil state shows it was never an actual effect to be had, it just feels like it worked because if your trying to go that quickly there was a lot of adrenaline and inertia making it feel like it took a LOT less force than when loading slowly, thus the misunderstanding it was being sucked inside.

[@MrGeorocks]

@@SheepInACart thanks for that

[@DK-ed7be]

No you don't. You may have loaded quickly, but there most certainly wasn't a vacuum to assist loading.

[@SleepyGuardian_]

@@DK-ed7be the dude literally just explained that there was no vacuum assist despite common belief. Someone clearly didn't pass their reading comprehension test.

[@johndonlan5956]

I used to work at a company where we would produce sabot petals for experimental new designs. Those suckers are difficult to make! (But there are tricks to every trade.......and we knew all of them -- and invented a few, as well). I love your video! You did an excellent job of explaining the construction and function of 120 mm tank rounds. (I love your tongue and cheek humor too!)

[@n5syr01]

Ahhh, aftcaps. I remember when we first got our A1s ha ing come from 60A3s. The aftcap deflectors on some tanks would cause the aftcaps to hang on ejection. And, not alway because the loaders were a bit too quick saying the main gun after it went boom. You listen on the jump frequency and you would hear "aft cap! Aft cap!" Overand over. And the loaders would normally already have the next round in their hands to load, but the deflector was in the way. Until we finally got everyone and everything dialed in, TCs and the loaderswould either kick the deflector, or knee it upwards. You could tell the tanks that hadn't got it dialed in yet as their loaders wore a knee pad on the leg used.

[@kickthesky]

Yep. We were all used to hot loading the M60A3s. That was the only way you would get your times down for the gunnery tables. Then all of a sudden we couldn't do that with the M1A1s we transitioned into. Took a lot of adjusting to it.

[@ab5olut3zero95]

The dern aftcap deflector is still a pain sometimes. A squirt of CLP and it usually clears up pretty quick. Either that or just be prepared to kick it.

[@macnuke4771]

Very cool stuff. Finally happy to have a visual representation to show my family (when the topic arises). Really like being able to see the full thing and the parts individually. Would absolutely Love to get my hands on some of these inert examples!

[@mhmt1453]

Thank you, Colonel, I always find your videos interesting. Having never been a tanker (nor artillery man), it is nice to be enlightened about such things. I’ve driven several tracked vehicles out of necessity, but I can’t say I’ve ever been in any capacity to fire anything larger than a .50 caliber, or a LAW. I do recognize Sabot and HEAT rounds, know which is prescribed for a potential target, but indeed, only have a very basic knowledge of how either functions. And, of course, not having attended either the Armor or Artillery schools, know little about handling said rounds. I was around Cavalry a lot while stationed in Germany, and am always eager to learn what these people did. Unfortunately, I am quite well-versed on how to “break track,” but that’s a particular skill I’ve found less edifying!

[@markpileggi643]

We used to grab the aft caps to use as ramp supports for our Bradley's. Made a nice flat surface.

[@prjndigo]

Sabot: not just a shoe, also a wedge or shim that something sits on. So cannons were held in place by sabot on pegs in the deck. So-on etc. Because NOBODY who has to walk through a shattered glass and horse shit filled street is going to toss the only pair of shoes they have into a machine. Sabot also refers to the block on a stick or "paddle" like object you place between the maul and what you're pounding on to protect the maul.

[@TheChieftainsHatch]

Unlike the Star Trek quote (I didn't want to spoil folks' impressions), the term 'sabotage' quite possibly refers to actions conducted by those members of the workforce who were the sabot-wearing crowd instead of normal shoes.

[@robertsmith4681]

Native French speaker here (Canadian), sabot for us always meant Dutch styled wooden shoe, "sabotage" being the act of throwing said shoe in a gearbox or whatever to jam it up. I vaguely recall it having it to do with 19th century protests against industrialization.

[@zemog1025]

@@TheChieftainsHatch So we could have Bruno Maliotage.

[@jakeaurod]

Sounds like "pattens".

[@jic1]

And of course in English as well, the word 'shoe' is often used for things other than footwear, for example the component that provides friction in a drum brake, or a box cards are dealt from in casinos.

[@sixstringedthing]

Not even one minute in and I've already learned that "inert" is the exclusionary form of the word "ert" and that firing a training sabot while set to HEAT is kind of a bad thing. This man is a veritable fountain of useful knowledge, may he be blessed by whatever deity he prays to, if any.

[@treyhelms5282]

Always informative and entertaining. Thank you Mr. Moran.

[@aqui1ifer]

If you’re going into this much detail in class 105, I’d love/dread what info you’d have in 200 series lectures

[@GraczPierwszy]

dzięki za info, no może być jak na dzisiejsze czasy, ale to się może w każdej chwili zmienić

[@giroromek8423]

A new friend for the shillelag casing?

[@steveturner3999]

Thanks for the info Chieftain. Looking forward to the next video.

[@gregoryf9299]

Very cool vid. My dad worked at Picatinny Arsenal for years, designing rounds like this. I remember him bringing home some sabot pieces.

[@dougstubbs9637]

Ok, long one, please be patient. The butt stub is originally a 1943 Rheinmettal design for the virtually unknown 8cm PAW 600 anti tank gun, the first application of the Hi-Lo pressure system. While trials continued on this weapon using a regular 75mm shell casing using either a metal or plastic blowout disc to complete the hi low bit, Rheinmettal was developing a new shell, using exactly the butt stub design you have, but using a newly developed propellant explosive, again another brilliant late war economy development called Nipolit, a substance which used only 43% of the nitric acid used to make ordinary TNT. The other property of Nipolit was it’s amazing mechanical properties, being able to be machined, able to be threaded etc. the whole idea was a lightweight HiLow pressure gun, and cheap ammo, no shell casing, the design of the butt stub controlling the pressure release from the propellant, all while maintaining obduration within a reasonably traditional breech design. Krupp had a new anti tank gun design called 7.5cm PAK 41, a Gerlich system squeeze bore, which was rejected in favour of the conventional PAK40, but a paper study was started to combine the unusual Krupp PAK41 design, Nipolit base stub shell, HiLow squeeze bore in a smaller caliber round. The desperation is the mother of invention situation was alive and kicking in late war Germany. The only other design of HiLow gun I know of is the 90mm Swedish IKV 90, and I can not think of any squeeze bore design post war. And, once again, no research is ever wasted. From 1943, to the Leopard 2 120mm gun…..you can’t extinguish knowledge. Cheers. PS. Don’t forget the breech design for the L11 120 rifled gun on Chieftain etc was lifted directly from a WW2 German infantry gun.

[@FeedMeMister]

Fascinating.

[@23GreyFox]

So the ammo is a 100% German design? Didn't know that.

[@felixthecat265]

You are mixing up several ammunition design principles here.. The ubiquitous M79 Grenade is a hi-low design. The principle is used in a number of munitions including the LAW80 system in the spotting rifle Nipolit was an explosive made from recycled gun propellent. It was used by the Germans at the end of the war, mostly for making grenades. Nothing to do with propellent. The Pak41 used a conventional (not HI LOW) charge system but had a tapered bore allowing the use of APCNR projectiles. This was also used in a modification to the UK 2pdr Littlejohn system. The point of a Hi Low system is to achieve low velocity large calibre which is not the aim of kinetic armour piercing systems.. the Gerlach can be seen as the logical opposite of the HiLow system as it is LowHi!

[@stevewatson6839]

Do you have sources for all this; and where does the info for the IKV 90 gun come from? Thnaks.

[@j.f.fisher5318]

No. Lol.

[@TobiasBerggrenBoy]

I have never seen a grown man trying to hide his giggle as much, and on so many occasions as Cheiftain does in the first minutes of this video. Every time he as much as glance on the round and even the spent casing, you can see his whole face lights up for a fraction of an second and I would assume a whole lot of memories running through his head at that point. But you pushed through Nicholas with an excellent presentation, and without a single ”Lawn dart goes boom, *insert Neil DeGrasse sound niiiiyaaah and then says hello to the inside of the target, the whole inside of the target. Thank you and keep up the good work.

[@mikethompson2650]

About the end cap, those holes make me think of a mortar round. It also has holes on the stem above the fins that allow the initial charge to bleed hot gases on the small donut shaped propellant charges so the mortar crew and "dial" in the range.

[@robertsmith4681]

When you think about it, those are indeed basically mortar rounds with extra steps, instead of "cheese charges' you have a combustible case.

[@Iceberg86300]

​​@@robertsmith4681ou have any info on those cheese charges? Like a technical name or designation/how they work? My Dad told me about his early days & the different propellant bags & "cheese" that goes into making up a howitzer round but when he went AGR (early 80's) his MOS changed & none of his subsequent units over the next 20 years had big guns. So while he can still quote a plethora of army regs that facilitated getting his job done more effectively, he can't remember the official designation or description of "cheese." Edit: could have mortars - but pretty sure it was caseless howitzer rounds built in the tube - but that could have been misremembering. He's old. LoL

[@robertsmith4681]

@@Iceberg86300 They are basically just linen bags filled with gunpowder. I assume the name got picked up because those powder bags often look like a wheel of cheese.

[@felixthecat265]

@@Iceberg86300 Charge Increments

[@ovalwingnut]

Thank you "Chief" -> Very InTeReStiNg... Thanks for injecting some lightheartedness into such a serious subject. Cheers from So.CA.USA

[@prjndigo]

pistol and rifle ammunition uses a swirling jet of a comparatively large size to inject the combustion into the powder, the most notably neat one is .22 rimfire which creates a central jet slightly offset from the initial firing pin strike towards the other side of the cartridge - thus one of the reasons the firing pin is in a strange location. (I've seen a .22 rimfire with two pins tho) The flame wave propagation rate is the same but in the larger ammunition like used in tonks (tracked wheeled boomsticks in general) you can end up with exceptionally low initial chamber pressures and over-pressures further down the barrel with enormous flames shooting out the end setting tents, sheep, bushes on fire if you don't initiate almost all the combustion at the same time. You want a conflagratory not a volcanic combustion or you simply won't get the blow-by pressure necessary to maintain the lubrication of the projectile out the barrel. This gets interesting with the fact that the larger tank bores actually fire the propellant on fire down the barrel WITH the round. The 16" guns on battleships do this as well - beats waiting for the pressurized conflagration to fart enough to push the round out. It gets very weird but makes sense if you look at it.

[@mikep490]

Well stated. When you have 20+ inches of propellant it'd take a long time (and a long barrel) to ignite it all with a standard primer. The central stem ignites the center of the propellant all the way up to the fins on the dart (roughly half the lenght of the casing).

[@jintsuubest9331]

The latest rod in service generally all got their fin almost touching the actual base plate (they delete the primer stick). Guess they find another workable solution to light everything up in a timely and efficient manner?

[@Mystickneon]

@@jintsuubest9331 Most likely voids in the propellant, providing an initial flame path over a larger surface area.

[@felixthecat265]

100% Nonsense... ..just sayin!

[@phil20_20]

Static electricity buildup. 😃😮😢💥🎉 Nice to know more about the HEAT round. I assumed there was an explanation for a flat front, but didn't know what it was.

[@thorhh]

"...Dart sized holes on anything in between.... And outside of brown pants for the crew..." I held until that point. Well done Chieftain :D

[@malusignatius]

"Since I just happened to have one here..." So many great vids have started with that sentence.

[@davidjernigan7576]

The flash tube coming ooff the primer should cause the powder to burn the length of the charge radially outward for more even combustion. It may also be done due to having the consumable casing so that is the last thing to burn rather than the casing burning from breech end forward and the charge shifting toward the breech.

[@jackroutledge352]

It most certainly was interesting and informative. You condensed more into that 10 minutes than an entire discover channel subscription.

[@looinrims]

*Why is there a 120mm packet of destruction sat on your desk and you’re slightly off center?!*

[@elaqgarahulelpon1479]

It's so powerful it moved him 6"

[@robertsmith4681]

It's his emotional support APFSDS so the emotional support TOW doesn't feel lonely ...

[@TheChieftainsHatch]

It's a Shillelagh, not a TOW, but close enough

[@grumpyboomer61]

Because every Irishman needs a Shillelagh.

[@robertsmith4681]

@@TheChieftainsHatch My bad, I don't know what that is mind you since it's the first time I hear that name ...

[@coaxill4059]

I remember someone on youtube trying to break down a HEAT round, possibly giving just another essentialized version. He said that the liner was basically particalized, turning into little fast and hot moving particles that were still solid, and all directed towards a small point.

[@scottremish1456]

Gotta' say, like the short format videos. My brain digests the info better than it would moving one subject to the next.

[@DD-hz3ts]

I'm glad you mentioned chall as using THREE piece ammunition So many people forget the Tube, Vent Electric (TVE) is a piece and that it is fed in a 10 rd internal mag

[@Alpheus1151]

1:14 Propellant doesn't detonate, it deflagrates.

[@briansmithwins]

Only the most pedantic of people would post this. Which is why I was in the comments. 😊

[@TheChieftainsHatch]

Fair enough

[@kanrakucheese]

I want a judge who realizes this to see the federal definition of a "firearm" during a case.

[@ryanj610]

@@briansmithwins TheChieftan is someone who probably would prefer the correction for future use. The HEAT section at the end shows that well.

[@DrSuperHater]

thank you for explaining the casing burning off

[@prjndigo]

Tidbit to add to the two panels on the shaped charge at end. The shape charge produces a critical fluid of the metal which contains enough combined energy through velocity and heat to _erode_ the struck metal/concrete/quartz it strikes. Part of the point of chobb armor is to have rapidly changing layers of chemistry with additional inhibitors. This is where the electrostatic grid defense system comes in (BAE iirc) in that it converts the critical fluid into plasma by simply grounding a high voltage charge through the jet to the vehicle body which simply goes on to paint a slightly more radar reflective surface on the target behind the grid. Such targets can be neutralized for the most part with two rapid strikes from RPG or simply the blast from an actual tank HEAT... or rain, bushes, a leaned rifle, Pv1 D.R.T. and so-forth. There is a fairly broad leeway with HEAT in that it needs to work from -40 to 140°F so over-kill is the order of the day. Over-penetration is one of the problems that the German HEAT mines are experiencing in Ukraine right now. Luckily they're over-penetrating through the carousel most of the time.

[@HanSolo__]

I'm sorry, but I wasn't able to translate it (understand the point) even with Google Translator. The thing I barely use while reading or writing comments.

[@mattz1230]

This is beyond wrong. It's literally gibberish.

[@glenndean6]

That tube you called the "primer" is actually the flash tube, which distributes the energy from the detonation of the actual primer at the base of the round to the propellant bed. In 120mm only the APFSDS rounds have flash tubes; HEAT/MPAT/OR/CAN do not.

[@TheChieftainsHatch]

Why didn't you say so before I recorded that?! :p

[@glenndean6]

@@TheChieftainsHatch I'm happy to pre-clear your videos. ;)

[@jakeaurod]

I remember hearing HEAT shaped charges described as producing a plasma jet, but I've hear more recent discussions referring to it as a "lance".

[@Bird_Dog00]

It's not plasma. Afaik, the metal of the liner - usually copper - even stays in its solid phase until it starts to go through the armour.

[@mattz1230]

@@Bird_Dog00 Hey!! Someone read their TM! Good for you!

[@mattz1230]

LOL, no.

[@Bialy_1]

The jet temperature is only slighty over 600 deg C and melting point of copper is 500 deg C higher... plasma is the next state after gas state -> the gas is so hot its starting to lose electrons from kinetic interactions betwen atoms->100% wrong idea. It is superplasticity caused by high speeds that exceed speed of sound in this metals...

[@mattz1230]

@@Bialy_1 CORRECT. Someone is either a materials science engineer or took good notes in ACOF class.

I am quite envious of those visual aids :) Nice Video. I always wondered why the HEAT Rounds are so flat, or can be so flat.

[@LazyLifeIFreak]

Reading about HEAT rounds and how the round actually functions, I'm reminded of a time when I was allowed into a workshop, just out of curiosity to what was going on and I was met with what was called a 'friction-stir-welding' machine-setup. I must admit it was quite fascinating/mesmerizing to see aluminium bars meld together like playdough and become one singular piece without the use of filler like in TIG/MIG welding.

[@HighlanderNorth1]

I'd like to hear more about that incident.

[@michaelbread5906]

My dad does aerospace, and he told me a lot of the guys in their 70's and 80's have been brought back to teach the youngsters. The schools haven't done enough education, and the real scientists in the field are still required to pass the torch.

[@elmaxidelsur]

this was WAY more complex and interesting than I expected. Thanks :)

[@ManinOdessa1886]

Awesome and informative. The armchair has more knowledge than ever. No one like it up’em

[@adventuretarian8191]

It must have been absolutely fascinating being on long missions with you!

[@rogersmith7396]

If you did'nt maintain a steady supply of Irish creme life was hell.

[@adventuretarian8191]

With the 'said supply of Irish cream' I'm sure the conversations would have been unforgettable!

[@robertsmith4681]

I can just imagine the poor, bored loader having to listen to him incessantly nerding out on track suspensions and going "we've been up for 3 days, sir, can I just go to sleep ?" lol

[@rogersmith7396]

@@adventuretarian8191 Yeah we would find a shady spot and radio HQ the tank was broken and Chief would get smashed. You can load a couple of cases of booze in those 120 mm tubes which is the main thing they are useful for. I usually just worked on my college English for an associates degree.

[@craigcooknf]

Brown pants. LOL. You were very much in the zone when presenting this. Very informative and entertaining!

[@bierce716]

Which would you least like your tank to be hit by: the dart, the HEAT, or a squash head?

[@AbramsGunner]

Yes... lol

[@qasimmir7117]

The worst would be the dart, then HESH, and then HEAT.

[@tackytrooper]

@@qasimmir7117 It really depends on the tank. Older tanks, like an M60 or T-55, that had homogenous steel armor would get wrecked by HESH, but modern composite armors effectively nullify HESH (its method of effect only works on homogenous steel.) And as Mr. Moran stated, if your "tank" has pathetic enough armor, the dart might just icepick through without doing much of anything. This is what was suspected to have happened to the BMP that managed to score a kill on the Americans during the battle of 73 Easting.

[@paulmurgatroyd6372]

@@qasimmir7117 One after the other?

[@cmck472]

That would come under the heading of a really bad day...

[@markholub97]

I’ve always wondered where the rest of the casing went. Tank firing videos were a magic trick to me. 😂

[@princeoftonga]

Is it just me or is the emotional support Shillelagh giving a worried look at that 120 round?

[@patriotstate]

In Star Trek, James T Kirk pronounced it "sahh-bahhh(short a)-tahhj

[@kimmer6]

The HEAT 120mm has tail fins that look like it came off a mortar round. Yours is missing the tail cone and fins.

[@fabiogalletti8616]

guess than hitting soil both bend the fuse AND did bad things to tail, too.

[@kimmer6]

Here are some inert 120's belonging to my friend. In 2014 I made up some fiberglass ''combustible'' cases that he cutaway and built some really cool museum pieces. I should have made a few extras to keep for myself. A pair of these complete rounds standing guard at my front door would have been really cool. kzbin.info/www/bejne/paSseHudYr2WiNk

[@losthart5577]

Ryan McBeth brought me here. I like it. Really informative, I like what you've done with the place. Great channel.

[@anthonyrosendahl2817]

Since the Marine Corps did away with tanks, I never got to ask what happened to the shell when fired. Thank you, as this has been bugging me for years. Plus I can no longer tell someone of higher rank that I’m with 1st tanks when they’re yelling at me. (I most certainly wasn’t)

[@joechang8696]

120mm tank gun, an excellent choice for home defense - if you are Ukrainian or other nationality too

[@zchen27]

Smoothbore as the Founding Fathers have intended.

[@andersjjensen]

Yes. It is exceptionally good for home defence. And we all know that hostile homes can be anywhere, and you never know when you need to defend against them. But with one of these suckers even the most sturdy hostile home will become rubble in an instant.

[@ronchappel4812]

If it's not allready in the constitution im sure someone will intepret it as such

[@edward9674]

@@zchen27How do i fit my tank inside my house? In case a robber breaks in.

[@zchen27]

@@edward9674 In the strictest sense you can probably just lift the gun out and stick it onto some sort of cradle at the top of the stairs. Remember the Founding Fathers don't have fancy pancy internal combustion engines!

[@DeliveryMcGee]

On overpenetration: I once read the detailed after-action report from 73 Easting. There were rather a lot of Bradleys (not THAT many, but enough to make one think "that's a lot of oopsies") with a "small, slightly radioactive" hole in both sides. In a lot of cases, the crew didn't even notice. Yeah, there was only one type of gun in that fight throwing DU lawn darts. Some were genuine blue-on-blue/mistaken identity, some just happened to cross between an M1 and a T-72 at exactly the wrong instant.

[@dmikulec]

In the mid 90s there was report on 60 Minutes about a group of soldiers that were told to wash off a destroyed Abrams. They wore fatigues for the task. When done, a bunch of officers showed up in NBC gear with Geiger counters to check their work. The officers in the NBC gear told them to clean it again as it was still radioactive.

[@jarink1]

DU dust is nasty stuff.

[@mattz1230]

@@dmikulec No. That's just wrong. There were no penetrating armor hits.

[@mattz1230]

No. there were not.

[@vksasdgaming9472]

@@jarink1 It is not nasty stuff because of it's radioactivity. Chemical toxicity is way worse thing.

[@jondavidmcnabb]

Best tank round video on KZbin!!!

[@cpconner93]

Where does one just find a 120mm round just lying around?

[@robertsmith4681]

Surplus market and gun shows, when you get lucky and your pockets are deep enough to actually buy it when one comes up ...

[@condotiero860]

America

[@aevangel1]

I have a 76mm inert just laying around....

[@kimmer6]

There was a guy in Santa Maria, Calif, who had a warehouse full of collectible ordnance but he retired and sold almost everything off. He had everything. I saw a crate full of 8''-55 brass USN propellant cases in there from automatic gun Salem Class ships and everything a collector could want. He even had 1900 pound 16''-50 inert target practice battleship shells in their original shipping crates and sold sections of 16'' gun barrels with a brass nameplate that gave the barrel serial number and when it served. Inert ordnance is getting rare and very expensive these days.

[@condotiero860]

@@aevangel1 that's pathetic. those are rookie numbers. you gotta pump those numbers up. i want to go to sleep with the certainty, not the belief. That if russians invade downtown Austin, you can hold your ground until the National Guard arrives.

[@Scarlioni]

Thank you for the printed blurbs at the end. I've mentioned to fellow 40k players that we sort of already have plasma weapons because of HEAT rounds. It's evident to me you have had the same question and poked around some. There is cavitation plasma in there, but it is the result of bubbles being instantly formed in the now boiling armor, not the cause of the damage. The 80s would have been around when research into cavitation plasma began. Marketing guys must of saturated it back when and it's knocked around since. Like you I have never found a decent layman's description of what a HEAT round does.

[@KibuFox]

I seem to recall that during WW2, Russia fielded a Sabot round which had an inordinately long dart. Twice the length of the one held up in this video. Akin to the M829A4 round. If memory serves, the Russians did this to put more penetrating power behind the rounds, with the theory of the day being that the longer penetrator would brute force its way through the armor of vehicles like the Tiger II, and heavier German vehicles. However, the various metals required to make such rounds were in short supply, to the point that crews were only given one or two of them. Reportedly, firing these against anything other than the biggest German vehicles, was an easy way for someone to draw the attention of the Commissar.

[@JakeDanczyk]

Not sure if you are recalling correctly. There were Tungsten-cored APCR rounds in WW2, which were rare and issues in limited quantity, but those are not darts. Possibly you saw a round still in its case, and that assembly was what was longer than the dart Chieftain holds in this video?

[@jintsuubest9331]

Sounds like bs. The material used to make early rod are simply tool steel. The carrier is aluminium, but you can make it out of steel if needed to be. Rod physics is not well known until relatively recently. Against most german vehicle including panther, they need a rod thats roughly 200mm in length and muzzle velocity of roughly 1500m/s. Steel need to have velocity just a little below1300m/s to erode. If you are not doing erosion, simply making a bigger diameter steel slug is a better solution as that allow a lower muzzle velocity. We know british has some limited success on sabot separation at the end of the war, we know german does not have any workable solution for sabot separation, the earliest sabot round used by russian is in the mid 50s, well beyond ww2. And if Russian actually develop such projectile, why they develop and issue apcr?

[@SheepInACart]

@@jintsuubest9331 Tool steel is not a particular type, its a common wording that spans a range all the way from regular low carbon steel thats been tempered to exotic alloys. Likewise some of the aluminum grades even today are among the most restricted materials internationally, used only for flywheels in guidence systems and centriguges for nuclear enrichment, and global supply of all grades is a hundred fold what it was back in the second world war. So your suggestion that its "just aluminum" thus must be easy to source is equally naive. Although in that case many carriers of the time where wood, ironically sourcing the right wood was equally challenging due to the requirements of balance, dimensional stability, high forces and concerns regarding moisture ect, all mandating not just a very limited set of tree types, but particular sections and grain patterns. Russia, Britain and USA all did issue small numbers of sabot ammunition, but accuracy issues at range, concerns regarding gun compatibility and issues with discarded petals on friendly positions meant it was FAR from a clear answer as future of development. Never heard or seen a super long penitrator from the USSR though, that sounds like it would compound rather than mitigate the development issues they actually had, while not solving an actual problem (as much as modern fanboys rage, tigers armor wasn't a concern for the new types in service even then, instead the fear was that a lot of the vehicles and especially towed guns actually on the front lines where NOT modern, and where much smaller... at the extreme end a lot of early "anti-tank" 37mm's served till wars end, and would have been of little help against even the late war Sherman).

[@frankgulla2335]

Thanks, nick. Great summary of the two main types of tank ammo these days.

[@isleofthecheetah]

How the hell did you manage to sneak one of those in your house?

[@Lo-tf6qt]

He asked an E4 to "Strategically Transfer Equipment to an Alternate Location"

[@Xander_Zimmermann]

He tactically acquired it.

[@JBall-hd8bw]

Rank has it's privilege.

[@ekscalybur]

@@Lo-tf6qt The proper E4 was already doing that and was immediately glad for the answer to the question "Just wtf do you think you're doing?"

[@sheriff0017]

Having a VERY reasonable spouse would help.

[@DanielLopez-up6os]

The chieftain is the only that Can pull this off and with this awesome humour.

[@jonesy279]

“Inert. Meaning it is not ert.” I love your work Chieftan 😂

[@TheEvertw]

"This, is a Bad Thing" That is my quote of the day.

[@CMSixSeven]

Chief, Half a second after you said the word "Sabot", the Star Trek VI scene popped in my head.

[@nathanrw7971]

Propellant burns- the more uniform and consistent the burn of the powder stack, the more consistent the velocity produced. This is extremely important at the extended ranges tankers would prefer to shoot other tanks from. I won't say there is no chance the long primer contributes to safety; it may very well prevent pressure spikes. But if I had to guess, it's designed that way more for consistency from round to round than anything else. It's a lot easier to come up with an accurate firing solution, if your velocity standard deviation is like 10-20, rather than 80 or 90.

[@jpc6235]

That's s a big one, Nicholas !

[@gallendugall8913]

This was very interesting. A little I knew and a lot I didn't. Thank you.

[@deepgardening]

Thankyou! I feel like I've caught up a bit on the tech of armored mayhem of the modern day. (I was one year too young to get sent to Indochina and got interested in other things) Very good to see the hardware in your hands!

[@tiivc]

This is a really tremendous presentation.

[@peterconnan5631]

I did indeed find it interesting and informative, thank you. May I request that at some stage you explain tank transmittions?

[@michaelwoodward5787]

Great video! Never saw any of this up close.

[@GNML6836]

Great seeing you at Aquino last weekend !

[@Anarcho-harambeism]

My ltc would run with one of these for pt, always fun to see

[@drderper]

The primer tube holes are covered in such a way that the primer will perforate the cover at the pressure required to properly ignite the main propellant. The length ensures that the propellant burns both evenly and more simultaneously, rather than from the base all the way up like in small arms. Optimizes the max pressure

[@zacharylovelady9265]

I'd love to see a video on the "Canister Shot" round that many Nato tanks can fire. That round has always intrigued me.

[@Thorgon-Cross]

Ooo yes, the good old buck-shot for cannons...

[@davidcorriveau8615]

Hand crank...like the older field telephones used in WW2. Cool.

[@vinnywelsh]

You have the best Pool Room mate!

[@mikep490]

I chuckled thru the video; a lot of humor for such a serious presentation.

[@johno1544]

Never thought much of the danger of those Sabot petals. They probably tumble in all crazy ways and possibly skip off the ground

[@talon262]

Nice way to slip in a ST VI: The Undiscovered Country reference there, Chieftain...

[@scdoty777]

As a lowly 12B sapper drunkard with dynamite, stand-off for a shaped charge is essentially like focusing a lens. However, different surfaces require different Stand-off distances to get a proper hole. For example, steel vs dirt, vs concrete. As the Colonel shows there is a fixed distance for HEAT rounds. For demolitions ( like blasting a bore hole in dirt) you have to calculate stand-off.

[@crsidney]

It's the Chieftain. Of course it was interesting and informative!

[@ZurLuften]

First thought: "Bringing live education examples from work I see. I am sure no one is going to miss that one"