What Are Those Bulges on Tank Gun Barrels? | Koala Explains: Bore Evacuators and Fume Extractors

The only consistency among the guns of armored fighting vehicles, is that none of them are consistent. Whether it's longer barrels, higher calibres, guns for different roles, they're all radically different... But early on on the Cold War, they all seemed to inherit one ubiquitous feature - that "bulge" part way up the barrel... What could that be, and should I see someone about it..?
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[@literal_f22]

TL;DR: That bulge on a tank barrel makes sure gases from rounds go out the front of the barrel, and not out the other end.

[@leehk23]

Thanks for the saved 12 minutes. I'll send you 5 in the post.

[@waffleMccoy]

oh god thank you so much you just saved me those 12 entire minutes

[@jerrybot7321]

Thanks, you just saved me 12 minutes.

[@Thoroughly_Wet]

Yes, this was definitely a video that covered a topic that could've been said it n as little as 3 minutes

[@waffleMccoy]

@@Thoroughly_Wet and thats why I didnt watch it

[@stupitdog9686]

I always assumed the barrels came in two parts and this was just a covering of the piles of Duct Tape holding them together.

[@ologhai8559]

*MacGyver soundtrack starts playing*

[@DBAllen]

Or a big Cherry Bomb muffler to make them sound cooler. LOL!

[@ace7843]

Home depo be like

[@charlesanthony4693]

The barrel is one solid piece. the bore evacuator slips down the barrell and is held in place by screwing on top with a locking ring. the barrel has gas ports so the spent fumes can escape as the round flies out towards the target

[@petequarles5350]

No sir. They all are one piece. The Connor tube on a, towed 155 Howitzer weighs about 12000 pounds.

[@capnfrankly]

15 years in tanks, I can tell you that even the small amount of propellent gases left in the turret can be throat catchingly acrid 🤯

[@yelsew816]

Wow, that is a smell I will never forget; the acrid, eye-watering smell of propellant.

[@baconatordoom]

Smells amazing. There's nothing like the smell of gunpowder and diesel exhaust.

[@abas656thegodemperor9]

​@@baconatordoomnot gunpowder

[@rawleywagor4943]

Great vid! I always wanted to hear more about this. Quick note on the MK45 - it's not enclosed as you describe. There is always at least one sailor in the mount while it's firing at the EP2 panel. You even show a clip of a view up from where the panel is. That netting is connected to an interlock. The gun won't fire if that netting isn't closed. This prevents anyone from being up in the gun pocket and getting crushed while firing.

[@bloodmoon5744]

This kind of video doesn’t make me think “yea but you could have answered the question in 2 sentences” as much as a 20 minute video that doesn’t answer said question until the end, the first 80% of the video revolving around why the question is important and why so many people ask it. THIS video keeps it interesting. You get to the point, explain it, and talk more about it. I like videos like this.

[@random12fps72]

Yeah no, you don't have to bullshit everyone. Even with all the whys ifs, and hows it can be summed up in 5 minutes tops and be twice as interesting. The real reason why all these videos are 10+ minutes is for monetization.

[@random12fps72]

@@sterloin3307 It's true though lmao. Keep wasting your time my guy

[@jaywhisonant4164]

Well, you can't forget to make at least 1/3 of the video into a totally unrelated ad.

[@thevalorousdong7675]

@@sterloin3307 Oh look, a fanboy that gets insulted when his dad is criticized

[@michaelccozens]

@@random12fps72 Love that you're watching videos from a creator you assume is acting in bad-faith, therefore also assuming that none of the info in the video can be trusted in the first place. But, no, you're the smart one here. Mmm-hmm.

[@charlesanthony4693]

It is a Bore Evacuator which expells the gas from the gun tube after the round flies out towards the target.. I know I was a Tanker on the old M48A3, M60A1 Rise/Passive, XM1, and M1 Abrams. I was a Armor Crewman on the M551A1 Sheridan Vehicle.. The Sheridan and M60A2 do not have a Bore Evacuator. Both vehicles use compressed air to expell the gas and combustible casing from the gun tube. Both Vehicles have a Giant Size Air Tank and a super noisy Air Compressor to fill the Tank with Compressed Air. I remember removing the Bore Evacuator, using a cleaning rag, cleaning solution, and giant Q-Tips to clean the holes in the tube where hot gasses escape through the Bore Evacuator. We use to do this after going to Tank Gunnery.

[@cheapbro1156]

Thanks for your service man👍

[@ElijahSUUUUIIILIVAN]

Wow Thats cool I love to play the XM1 sheridan in world of tanks blitz! Thx man! 🤟

[@DK-ed7be]

Both the M551 and the A2 originally had a bore evacuator. Didn't work well, and didn't scavenge the remaining burning embers. The CBSS was added to correct that problem and those vehicles with original gun tubes had their bore evacuators welded shut. Later production models, of course, did not have a bore evacuator.

[@nudel23wot]

I think I'm right here when asking this question.. some tanks have these things at the tip of the gun which look kinda sick tbh but I wonder if they have a purpose because not all tanks have them and many just have a straight gun. For example the Tiger I got this thing on it's 8,8 but the Leopard 2 got a straight smooth ending gun.. can someone help?

[@charlesanthony4693]

@@nudel23wot it is a Muzzle Brake A muzzle brake or recoil compensator is a device connected to, or a feature integral to the construction of, the muzzle or barrel of a firearm or cannon that is intended to redirect a portion of propellant gases to counter recoil and unwanted muzzle rise.

[@anhduc0913]

"Is that a gas vent or are you just happy to see me?"

[@usgator]

Thank you. I spent 6 years in an armored cavalry unit, and two tours, and never knew what that was. I was just happy a tank had showed up.

[@LintSplinter]

Thank you for your service. Crazy part about tanks was in the early days of the concept a lot researchers saw a tanks only uses outside of trenches as “an effective form of reducing enemy morale” glad to see the reverse happens too

[@friedpickles342]

Well trained ic

[@user-dy1tl8hg6t]

Thank you for your service. My grandfather fought in the the Battle of the bulge attached to a tank unit.

[@usgator]

@@user-dy1tl8hg6t thanks. My grandfather also fought in the Battle of the Bulge. He was a BAR gunner in Patton’s Third Army. Ironically enough, the Third Army now has jurisdiction over CENTCOM forces so Army forces deployed in the CENTCOM AOR are technically under the Third Army. So I also have a Third Army combat patch. I have my grandfathers Combat Infantryman’s Badge and Third Army patch and my CIB and Third Army patch mounted together in a shadow box.

[@High_Octane_YT]

Thank you for your service, which tank were you in? Leclerc, Abrams, Leopard or Challenger

[@ms-1236]

They're not "incredibly difficult to clean" @9:27 (at least not on the M1-series Abrahms) - just takes a little time to take off the shroud. Popping the bore evac is easy, and cleaning the holes is also. All part of tube maintenance.

[@ODST_Parker]

I could have sworn you covered this topic already, am I insane?

[@tigerbattle]

Reupload from Koala’s main channel, he’s moving all of his videos on these kinds of topics over from there

[@memeu7013]

@@tigerbattle yeah but I remember him already uploaded this to this channel

[@Gunsforbuns]

free cash re-grab

[@Deathbomb9]

@@Gunsforbuns more power to him. Either way I do remember this video bot the guy works hard on them and they are great and very informative.

[@Combat-Wombat]

@@Gunsforbuns It's a diffrent channel, not all watching ArmorCast watched his gaming channel, it fits the armor cast topic so why wouldn't he reupload that vid here?

[@_call_me_books_]

I have developed a recent obsession with tanks & appreciate your explanations. Thanks Koala 🐨

[@crazywarriorscatfan9061]

I've wondered about the bulge. Thanks for explaining! And I always love your humor!

[@kendodd8734]

Man I’ve been at so many parties in the past In tiresome company when a bore evacuator would have rearly come in handy

[@Menaceblue3]

@@kendodd8734 Is that a bore gas evacuator in your pants or are you just happy to see me?

[@BudiBudi-oe4kz]

Humor King indeed! How he said that line "while the munition round flies out of the barrel and does very nasty things elsewhere" really had me for good! 👏😂👍

[@davidduffy2046]

I thought they were hernias

[@VadoVoodoo]

When I was a squaddie, cleaning the smoke extractor was not 'incredibly difficult' to clean at all, having done several of them many times, I'd describe the job more as 'filthy greasy and sulphurous' and remember just after that job once wiping my hands with some filthy cotton waste rags and wolfing down a can of Westlers with beans and a cuppa tea. It's just a very dirty, greasy job, takes about 20-25 minutes for one bloke with the right tools.

[@johninnh4880]

My 105 mm on my M60A1 had one which worked very well. Not much gas came back into the turret even in sustained fire. Hot brass was the big problem. Not a problem with the 120 mm as it consumes the "case" leaving just the base. Got to love new technology.

[@traviseggl3794]

Only downside of the combustible case of the 120 is you have to be a little more careful handling them. We had one come apart when we tried to get it out of the breach with out firing the round. Gun powder all over the turret. We cleaned it up the best we could, shoved the base/primer back in the breach, and our Master Gunner remote fired it.

[@johninnh4880]

@@traviseggl3794

[@rogerrice1772]

The "JJ" series M60a1 rise/passive was a great vehicle!. Junior E6 tank commander, best job i ever had!

[@johninnh4880]

@@rogerrice1772 With the training HEAT rounds I could hit a 6" square at over 1200+ meters easily. I was flat out amazed how accurate the 105 was. Just imagine how much better the first round hit probability is with today's targeting systems.

[@user-lx9bz7wi1i]

You can add that the location of the bore on the Gun is a trade-off between how much gas you want to leave in the turret and the projectile speed. If the bore is near the end of the gun- the projectile will fly faster but more gases will be left in the turret. Also it's very clean to remove and clean.

[@ryancrazy1]

4:00 to clarify something here. I believe for these to be effective their NEEDS to be a semiautomatic breach. The breach needs to open at the right time for the gasses to flow correctly. i believe the puff of smoke is when the breach is opened. "For best results, the breech must be opened at the proper time, just as the forward momentum of the gases reaches its maximum, the peak flow. This means that bore extractors are normally used only on guns with semi-automatic or fully automatic actions, where the breech is opened and the shell ejected as part of the recoil process."

[@RandomGuy17768]

Cleaning the bore evacuator is apart of weekly PMCS on the -10 of the maintenance manuel. Mess around and go downrange with a dirty bore evacuator and you can have a flashback fireball inside your turret. With ammunition that has a combustible casing that can start a fire and possibly kill crewmen. We had a tank fire caused by lap loading, even though CID & the MI said it was a flashback. Killed the loader and driver. The driver was asphyxiated due to the halon fire extinguisher going off. The loader was burnt almost immediately. This was at Ft. Hood on the M1A2 Sep during crew qualifications firing the nighttime engagement's. I know all too well what it means to clean one...alot of CLP and leaving a light coat of GAA on it to help keep the rust off.

[@traviseggl3794]

You were battle carrying 120mm ammo stateside?? I had a tank commander (CO) that wanted our gunner to send a round down range at the night live fire at NTC with our ammo door stuck open. I was so glad when he refused. I thought for sure our CO was going to grab the over ride and send it anyways.

[@JustaMuteCat]

Koala, you know we came for the semantics, and stayed because properly explained things are great and honestly tanks are cool.

[@cmw9876]

Difference between men & women? Blokes know things about tanks. This is changing.😊

[@scifidino5022]

Wow, I just asked myself this question a few weeks ago! I tried to google it but kinda got lazy after searching for a few labeled images and decided to just leave it at "Well, now I know it is called a fume extractor and is used to clear the gasses after a shot" XD I am surprised how simple this system actually is!

[@marnusbooysen9397]

I love the fact that he correctly pronounced "Rooikat". Great video man, I love your content.

[@lemonkeyppgov3605]

10:53 The longer video is the reason i watch this channel so i don’t mind at all

[@andrewmcneil2110]

I love these educational vids. Please keep on keeping on.

[@darrenkitchin1842]

I appreciate your vids, just found this channel and my gosh I just love it

[@joshuagarcia874]

Thanks for the vid Koala! I've googled this before, but I didn't remember off the top of my head :)

[@mho...]

nice one, always wondered about the bulge & the "puff" of smoke! never thought it could be connected!

[@ecurb10]

Brilliant! Thanks! Straight to the point, without long-winded bla bla first.

[@CSmithUSMC]

You answered my question about T-54/T-55 bore. Great video!

[@kwyoushyt6356]

At this point I just wach this video just because I's you, I know a bout fume extractors but you make it sound interesting again

[@Follower_Of_The_Onions]

"ahemm" B U L G E S

[@Charliee_Woofy_Pz]

oh no

[@dirtydishes2148]

Thank you, appreciate the all the information.

[@c4wolf_]

Great stuff@!! Thanks for sharing your time n knowledge @!!

[@kingdarkem]

Great job. I had my book on building artillery and stuff at the ready incase you had bad information I could quote from it. You nailed it though.

[@chupacabra1765]

Decades, I've been wondering and speculating wtf those were. That ticks off a big box on my curiosity list. ThX

[@nickc8819]

I was thinking the same thing :)

[@raider762]

Always wondered about this. Thanks for the video.

[@icysteve46]

Wow. Thanks. I didn't need to know this. But I feel super cool now that I do.

[@magnificentmuttley2084]

Thank you Armor Cast. I always wondered what those bulges were. Now I know! Great info.

[@spacecase13]

I come here for the lengthy explanations. Please continue!

[@thomasglessner6067]

Another informational video. Thank you.

[@josephtutela1066]

never too much detail . Your real fans come to you for in formation!

[@mokhalifa865]

Thanks for the information!

[@ronron7763]

Thanks for kind info, i thought it was for coupling together two barrels to extend their length.

[@semperbetio]

As a former TOW gunner, I just realized how much armor ID I have forgotten. Cool video and thanks for the hard work.

[@robbenmitchell7949]

Tube launched , optically tracked, wire command link guided missile.

[@xflyingtiger]

I am glad that I watched this video. Thank you.

[@semco72057]

I always wondered why those pieces of equipment had those bulges on the barrels and glad you explained it.

[@jonbridge8064]

The French Char B1 Tank also used compressed air to blow fumes out of the barrel.

[@maximk9964]

I did wonder what they were, thanks for the vid!

[@yorkyleefairbank]

I always wondered what it was for and I used to know quite a lot about tanks because I shoot a anti tank missile in the military but didn't know what that was for was. You never stop learning.

[@kaneworsnop1007]

The Challenger II actually uses both over pressure and a fume extractor, I can't remember now why the fume extractors even there as the over pressure negates it's requirement. The air blow as you called it isn't anything fancy and I'd assume its similar in other tanks to the Challenger, it is in fact a biproduct of the NBC system, the filtered air entering the tank creates the overpressure which when the breach opens pushes the gasses out of the barrel. Also the loader doesn't manually open the gun breach after firing, the breach automatically opens and in tanks that have casings they are automatically ejected at this point also. Opening the breach manually would atleast double the load time as the next round couldn't be held ready to be placed in the breach immediately after firing.

[@rosmundsen]

I am so surprised by this channel, I do not know that Koala's could create content on KZbin.

[@morenofranco9235]

Excellent, Armor Cast. Thank you.

[@joplaane4813]

This channel is growing quick, well deserved Koala.

[@vieroboy]

Yay...12 min video to answer a simple question......nice.

[@kjellkriminell372]

"and are incredibly hard to clean" important point im glad you included lol

[@jimcraig8794]

Interesting trivia about most modern bore evacuators: they are filament wound fiberglass structures.

[@ReverenXero]

There is a location sensor in there as well. It verifies to the computer the angle of the barrel in relation to the tank. It's how it can fire on the move and maintain target tracking so well

[@traviseggl3794]

No there isn't, it is on the end of the gun tube. It is a sensor to update the bore sight after the gun has been fired a lot. When the gun tube heats up, it can start to droop, so you can do what is called an MRS update which is supposed to correct that. Every thing minus the muzzle reference sensor and the crosswind sensor that controls the main gun & co-ax is inside of the turret.

[@Aserash]

I'm just really impressed at your pronunciation of Rooikat. Best pronunciation by a Brit I've ever heard.

[@ArmorCast]

Cheers! Just gotta try and sound like Andy Serkis 😂 In all seriousness, my father’s family are all South African. Parents are separated, but it means I’ve been around the accent quite a bit when I was younger

[@georgeherod4252]

Good info, thanks

[@ssgusa]

I was on both M1A1s and Stryker MGS. It was easier to clean the bore evacuator on the M1 than the MGS. This is due to the 120mm being a fiberglass composite versus the 105mm is steel.

[@cjcristofalo6728]

It means the tank is happy to see you- you make my 105 puff up to a 120

[@Nemean-se5k]

i actually just thought these were for the balance of the gun, helping with stabilization or something

[@Copenhayden]

Actually, to help balance the gun, they get the heaviest crew member to sit on the end of the barrel

[@dontknowwhattoputhere2793]

@@Copenhayden imagine the recoil on your balls

[@Copenhayden]

@@dontknowwhattoputhere2793 No, I don't think I will. Thanks.

[@bigdaddydiesel5520]

@@dontknowwhattoputhere2793 I don't have to imagine, I was that heaviest guy.

[@nickc8819]

@@bigdaddydiesel5520 :O

[@yankeewithnobrim226]

There are some pretty good jokes in the video description.

[@Deathbomb9]

Now I'm gonna go look...be right back. I'm back...I only see a couple that could be turned to jokes.

[@donaldhollingsworth3875]

I loved shooting the M110 8" self propelled howitzer & the 105mm towed artillery howitzer's when I was in the Marine Corps. The 8" could put a round inside of a garbage can at 18 miles using a RAP round & red bag powder. Granted the M198 155mm could shoot out to 18 miles using a RAP round & red bag powder but it was hit or miss since the sights on the M198 were not as finely made compared to the sights of the 8" howitzer.

[@YourAverageUsername]

this man is underrated

[@georgerobert4709]

Fume extractors . As it says on the tin removes fumes from the barrel after firing using the recoil action of the ordnance, preventing them leaking back into the turret when the breech is opened to load the next round.

[@BoldUniverse]

I gotta say, I love YT and other channels that teach me something I didn't know. Even to the point where I didn't know that I didn't know.

[@User0000000000000004]

Teach you something about a gun, lie to you about a VPN. Wonderful.

[@Fiberglass_Insulation]

"What is that bulge OwO" "That, my dear, is a fume extractor"

[@puncherofwomenandminoritie4625]

The tank is just happy to see you

[@prolifedoc]

Thank you! I have wondered about this bulge for 20 years. I even asked a tank crew member that was in Desert Storm and he did not know. Well done.

[@chrisperrien7055]

People not following their PMCS schedules. (preventative maintenance checks and services.) Pulling the bore evacuator is something you are supposed to do annually(IIRC) or after X rounds fired. It is a minor PITA to do so many people skip it. Obviously he never pulled/slid one off its position or he would have known what it was.

[@Nyante]

@@chrisperrien7055 he might know what it was, but not its function

[@thewildman8544]

If the tank crewman didn't know what it was or it's function, he was either a boot, an idiot, or both. They freakin cover this at Ft. Knox. I mean, it's basic knowledge for a tanker. Just sayin... USMC 1811

[@chrisperrien7055]

@@thewildman8544 Please note, the Armor School moved from Knox many years ago to Ft Benning, so I am sure armor training standards have devolved to "Infantry" levels of intelligence/ignorance ;) LOL :( Granted the post was about a DS "vet" but still you should use past tense about Ft Knox and the Armor School, even for the Marines too, , and it is a dam shame. Regards, Brother

[@thewildman8544]

@@chrisperrien7055 Well damn, I guess my age is showing! Lol. Thanks for correcting me. I was at Knox waaaay back in 1989 and was on the M60A1RP. Had no idea they moved to Benning. I guess as I get older the less I keep up and more outta touch I get. But still, that tanker should've known what a damn bore evac is! If I'd have heard that as his TC, he'd have gotten smacked in the head and had to PMCS that bore evac everyday for a freakin week! Lol

[@jcs6347]

Bore evacuators primary job is to pull smoke and dangerous fumes from the gun turret so the crew can see to reload and to acquire targets and without inhaling dangerous fumes. Look up the battle of the Monitor and the Merrimack where we learned these lessons. Bore evacuators are not hard to service. Two men to break it loose and both can clean it in 30 minutes or so. Once broke free, it was normal PMCS. Not at all difficult as you describe. Charles Anthony comment below are correct. After gunnery we cleaned it 3 days in a row along with the tube and breach to ensure it was cleaned and lubed correctly. Was in the 1st Gulf war with M1A1 and we never had time to clean it. Afterwards it was a bit of pain to break it loose after the rain, snow and hail, but other than that, normal PMCS. Informative video, thank you for posting!

[@hadesdogs4366]

In the old days you simply open up the chamber releasing all of the nasty fumes inside the turret of the thank as is then sucked out by a small fan or through the open crew hatches to allow for better ventilation

[@evilangel8194]

Good video as non military personnel just interested guns military hardware always wonder what they were

[@crazytrain03]

Army 19K here. I remember very fondly sitting on a BP(battle position) hearing the fire commands rolling out...as soon as my gunner shouted "On the way!", a massive fireball filled the tank. It burnt eyebrows and smoked us out completely. We had been shooting two crews off that tank all day, and the evacuator clogged it's ports. After that shit...we got real good at cleaning our guntubes and pulling our covers off the evacuators to clean them after that day lol

[@dynjarren5454]

Cleaning these were a pain but yes this about covers it Hell on Wheels

[@Killianwsh]

@4:35 It's good to see that cross on tanks again!! :)

[@ghettoewok3902]

The M109s gas blowout is also assisted by an actual air system that we activate within the vehicle before firing.

[@Deathbomb9]

I did not know this about those. On the Abrams we can help it with the NBC system if we are buttoned up.

[@ghettoewok3902]

@@Deathbomb9 yeah, it's not 100% needed to fire, as the BE still assists with this, but it helps prevent the gasses from flowing back into the vehicle after multiple rounds fired. So many times I'd have new gunners get a face full of smoke because they didn't switch it on xD

[@brandonm1881]

My guess was it was an internal intake cylinder with vent holes being at the barrel end side, in which gas is inhaled to the evacuator chamber, and then a gas piston or spring loaded sealed piston then forceably is pushed in towards the turret, then reciprocates back to the original position, in a single motion, or multiple motions, forcing gas and remnant gas in the barrel out into open air. But a no moving part vented gas diversion chamber is cool to.

[@WarHawk-]

The bore evacuator, at least on the 155mm M109Ax Howitzer, uses a series of check-valves consisting of spring loaded [large] metal balls fitted into holes along bottom of the barrel which is then protected by the bore evacuator cover - Former M109A2 155mm Self-propelled Howitzer Crew Chief (7 years).

[@sirfer6969]

A Scottish koala? Now I've heard it all....great video, sir...thanks =)

[@stuman01]

Very interesting - Thanks

[@robertkelly1434]

Ahh, the good old bore evacuater. Great fun to remove and clean... 👍👍👍😏😏😏

[@chrisperrien7055]

minor error- The Breech block opens automatically and stays open after a round is fired and the case is ejected.-semi-automatic. The loader does not have to open the breech except to load the first round. It is surprising how well the bore evacuators work, I had one of the vent- holes(of 6 on the cannon tube, under the bore evac. ) plug up on a 105 L7/M68 on an M60A3 while firing. Quite a bit of smoke/fumes came back into the turret though the opened breech after each round fired. Smelled like ammonia, assume it had some cyanide in it. Later we pulled the evacuator and cleaned out all the vent holes. Fume Issues like that or worse, also happen if the bore evacuator cracks or comes loose or someone shoots a hole in it with their roof machine guns. The turret will fill with a good bit of smoke if that happens, each round fired. Running the turret fan will make this initially worse, as it sucks air through the cannon with hatches closed . And the smoke/the fumes are somewhat toxic. Last note, on the 105mm L7/M68 , the bore evacuator was steel, on the newer 120mm L44/55 's , they seem to be some sort of fiberglass.

[@traviseggl3794]

Yes, the 120mm gun has a composite bore evacuator. Draws the smoke out of the breech and helps prevent a flashback in the turret..

[@quanohong572]

fiberglass ? like the thing they used to make rocket launcher tube ? that mean 7.62 bullet can do damage to the bore evacuator ?

[@chrisperrien7055]

@@quanohong572 At short range, especially from a tank's loader's or commander's MG position's, a 7.62 could pierce/damage even the old steel bore evacuators. They were only "about" 3-5mm thick on the sides, They are hollow tubes , not solid.

[@powertothebauer296]

Chris Perrien. It is not that the Gases are Toxic, if you let the Gases accumulate in the Turret , you blow yourself to pieces

[@chrisperrien7055]

@@powertothebauer296 I would disagree. No amount of those fumes inside a turret , would amount to a flash-fire, much less an explosion. The(fumes/smoke coming back into the turret) are expended carbon dioxide/monoxide , carbon flakes, and nitrogen/cyanide fumes from an explosion already "burnt". Toxic , but not really flammable , and certainly not "explosive". They won't blow up( or deflagrate) like "coal dust" or something like that.

[@joeabels3931]

I was on the M1 for a few years. Those help but the casing still lands in the tank and stinks like crap. The barrel is already open after it's fired. When I load the shell I would swing an arm back and yell up. when the gun is fired the breech would be open as it hit max recoil. the casing would hit the arm that I open, and fall to the floor. I would throw the arm closed so I could get the next shell in and at the same time it disarms the gun. only time re open the breech is when it's stored in the motor pool.

[@andybreglia9431]

I knew this from the early sixties when I served in the Army. The duct tape sounded too silly to be believable. First shot fired, the front part of the barrel will go downrange with the shell.

[@enoob101]

Heyyy the M26 Pershing shown at 8:50 is in my home town of Mobile sitting next to the U.S.S. Alabama 😁 I knew I recognized that ship. I did get to sleep in the crew quarters with my boy scout troop a couple of times 😁

[@imboredrly5478]

I come to this chanel to learn and maybe aply things you show us

[@kk6aw]

I was. Tank Commander on a Patton M47, we never had those bulges so I learned something today. Damn glad I didn’t have to play with those coffins.

[@gareththompson2708]

It does feel like you went into more detail this time.

[@cnjor2331]

i didnt know what was that for but i had my theory similiar as you showed that when round fires so gases have more space idk hiw to explain it

[@lancelotkillz]

You had me at the (clears throat) bulge . instant like 😁

[@DonForceFeedback]

I don't know if I missed it or you didn't know, but the early Russian tanks that were seen with fume extractors on weren't actually fume extractors. They had seen that western tanks started to have these bulges on the barrels and so did the same on their tanks, only it was just a concrete cylinder around a normal barrel for a while till they realised what they are actually for.

[@rob379lqz]

That little Scorpion is very cute. Could sell icecream bars to kids from it.

[@TerLoki]

Honestly bore evacuators in concept seem a bit similar in design to the one-way Tesla valve, if not quite in function. Since one uses the sudden difference in pressure, while the other uses a fluid's own speed against it to create turbulent flow and slam on the brakes.

[@petequarles5350]

I was a Artillery Weapons/Tank Turret Mechanic in the Marine Corps. In my heart, anything bigger than 105mm is a cannon. Cannon tube.

[@chzuniga1]

Siempre me había preguntado qué hacían con los gases residuales del disparo… con este video me aclaro todas mis dudas. Saludos desde Chile

[@Deathbomb9]

Bore evaluators arent that difficult to clean in many cases. The one on the Abrams simply slides up the barrel over the thermal shroud and you clean and follow the maintenance steps the same time you clean the gun. Theres also inspections that happen and those barrels dont have a long enough lifespan to cause the gas ports to become clogged. The pressure alone should keep the ports mostly cleared if you are doing your proper maintenance. I always hated getting back from gunnery with all the build up and never tried it but one thing crews might consider is running a wet brush through the bore after each table. I'm Afghanistan we taped two layers of shirts over the end of the bore to keep the dust out but also allow us to keep brush the guns when needed. Gun maintenance is the top of the list on a tank, artillery, or infantry support platform. These being passive systems do an amazing job and have been tested extensively to maximize their effect while not being massive. You still get some gasses from the cordite and being buttoned up as well as having the NBC systems one can help push those gasses out as well. This is all from experience on the Abrams and the MGS, other tanks might have different systems so dont jump on me if its definitely for you. I'd love to hear from other tankers and big bore brothers from around the world on this and what systems they can use to increase the effect or about their experiences. Death before dishonor. Love the people in this community.

[@ArmorCast]

Always a pleasure to hear from service members with real world experience! Interesting to hear from an MGS crewman too, I've always loved the design of that thing, though apparently actually FIRING them isn't all that pleasant. Couple gunners told me with the recoil, the sights like to come up and smack you in the chops!

[@shellyandjohncourtade8269]

You are correct that the FV101 Scorpion did not have a fume extraction system. This issue caused the British to deem the gun unsatisfactory because toxic fumes entered the fighting compartment.

[@xModerax]

I like the longer videos

[@BRUHM0M3NT.]

I HAVE BEEN TRYING TO SEARCH THIS FOR A LONG TIME!

[@User0000000000000004]

CONGRATULATIONS BRUV!

[@bendrenth441]

I've got another one, is it possible for you to explain how the tank gunsights get the elevation marks and how they're measured out?

[@kaneworsnop1007]

I'm assuming that your referring to axillary sights and not primary sights as they don't have them. I don't think it's anything more than a clever person doing the maths for all the different armaments.

[@feffe4036]

I have one of those on my screw together bench press bar.

[@de209hoth4]

thought it was apart of the hydraulic system for the recoil of the gun or something like that