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 Warpig1815 wrote:
Hahaha, I've just got images of some Space Marine stripping down an ork gun to find it just a box of metal bits, and then on the other side of the battlefield and ork stripping down a bolter to find a huge feth-off maze of barrels, cogs and other assorted .

You should post that.

 Warpig1815 wrote:
...I've just got images of some Space Marine stripping down an ork gun to find it just a box of metal bits...

"Um... Brother Valus... I think I just found you inside this weapon... and several of our brothers' torsos..."

Also, there's something that's easy to miss unless you look closely:





You see how close the ammo feed is to the end of the barrel? Clearly heavy bolters use a blowback mechanism. I look at the MP40, Uzi, Mp5, etc. etc., and none of them require special cooling mechanisms to work.

The picture of the M2 you showed is an example of a weapon that DOES need cooling because it sends rounds and burning gasses down a few feet of barrel. Not so much for bolt weapons.

Jimsolo wrote:You should post that.

Forgive my derpiness - post it where?

EDIT: @Ailaros - Now supposedly, the Heavy Bolter uses and electric feed and ejection mechanism, not a gas blowback system. However, I'm not too sure myself on the accuracy of this information as I read it ages ago on the 40K Wikia, before I realised that Lexicanum was far more accurate. This is the excerpt from the Bolter article:

'Heavy Bolters operate differently than other Bolt weapons. Instead of a firing pin physically striking the bolt shell to activate the projectile, a specific electronic pulse is applied in the firing chamber. Bolts are fed into the chamber by an electric motor, rather than exhaust gases cycling the action as in other Bolt weapons. Exhaust gases are used to generate the power needs of the weapon; the initial power and the impulse for the first round are provided by working a slide on the weapons side. These features enable the Heavy Bolter to maintain rates of fire that are physically impossible for a standard Bolter or Bolt Pistol.' - Warhammer 40K Wikia

BrotherVord wrote:
Applying real world physics to a fictional weapon in a fictional universe isn't going to work. GW could easily just say that bolters of all kinds are made from a special alloy that won't melt at the heat produced by continuous fire.

All that being said, part of the beauty of 40k and this hobby in general is that if you don't like it, you can convert it!

I've said this before and I will say it again, we are debating physics while talking about a world where men fly from one end of the galaxy to the other, in 5km long battle ships, to duel with swords.

@brokksamson - Obviously there are aspects of 40K that are simply ridiculous - that's what appeals to people who like sci-fi. But to discount all of 40K's tech/physics is shortsighted considering much (Not all obviously) of it is well within reach of humanity within the next 20 odd years. Men flying from one end of the galaxy to another - don't be so dismissive, as warp drives are already being developed albeit on a tiny atomic scale. Same for teleportation on an atomic scale. It's only a matter of time before we start scaling the tech up to human levels.

and we're going to use those warp drives on 5KM long battle ships? and when we get to our destination, we will have flown that entire length of space just to fight with swords?

I have a feeling we would advance towards something more like Star Trek, in which case one of the smallest ships known to the Imperium, a Strike Cruiser... is bigger than an entire Space Station in the realm of Star Trek.

Oh definitely, I'm not completely pulling apart your theory - I too can see no reason to fight with swords considering the sheer proficiency we have with firearms now. However it is worth noting that since powered armour is in development it could be that armour becomes sturdy enough to deflect conventional bullets, but cannot support the weight of larger ranged weapons capable of taking out opposing power suits. That would probably be the only time when we would need to revive swords as close combat weapons, and it's most unlikely.

On the subject of 5km battleships - 5km, probably not, but arms races often provoke bigger is better attitudes, just look at Great Britain and Germany's dreadnought manufacturing to see evidence of that!

 Arcsquad12 wrote:
I'm curious why the Heavy Bolter is such a boxy weapon. I actually don't mind the standard Boltgun, since it doesn't fire particularly fast. But the HB is different. It is a fully automatic grenade machine gun. And yet there is no heat dispersal that I can see.


M2 Browning Machine Gun. Equivalent to a 40K Heavy Stubber. These things produce a lot of heat because of the friction caused by bullets passing through the barrel. If you fire a machine gun continuously, you're going to melt the barrel. That's why you see those big jacket holes (thanks for the correction Amanita) around the barrel, they are there to disperse the heat between bursts.

With a fully automatic weapon like the Heavy Bolter firing massive shells at a high rate of fire, having a heat sink or a means to prevent the barrel from melting seems like a no brainer. But at least on the current models, there seems to be none. Is it because Games Workshop doesn't properly think these things through? Or because a featureless rectangle is easier to mold than a gun?

Or am I just sperging out?

It's because they had to match the aesthetic of the bolter. When you look at it all the heavy bolter is is a scaled up boltgun. Also, the way they keep them cool is by using the coolant systems that come stock in every plasma gun. You never hear it mentioned in the fluff, but the Imperium actually has the safest plasma technology in the galaxy. It's just the coolant systems get stripped out of the plasma guns to be used in other weapons.

 Warpig1815 wrote:
Oh definitely, I'm not completely pulling apart your theory - I too can see no reason to fight with swords considering the sheer proficiency we have with firearms now. However it is worth noting that since powered armour is in development it could be that armour becomes sturdy enough to deflect conventional bullets, but cannot support the weight of larger ranged weapons capable of taking out opposing power suits. That would probably be the only time when we would need to revive swords as close combat weapons, and it's most unlikely.

On the subject of 5km battleships - 5km, probably not, but arms races often provoke bigger is better attitudes, just look at Great Britain and Germany's dreadnought manufacturing to see evidence of that!

I'm an aerospace engineer. Space Travel is a cold, hard, unforgiving thing. I'm not saying we as humans won't eventually fight in space, but it will not be glamorous or at all like most Sci-Fi movies.

For one thing our ships will most likely look like this: http://www.fleetops.net/forum/download/file.php?id=13295 and for another we are going to be staying within our solar system for the conceivable future.

That said, at some point (if we haven't blown ourselves up, exhausted all available resources, or otherwise fallen victim to some catastrophe) I have no doubt our descendents will be doing stuff that we can't even imagine.

Anyway, I've derailed this topic quite enough.

Wow, sorry that image posted bigger than I thought it would! Anyway! Sorry for the additional De-Rail!

Thanks, actually. That ship size comparison is cool, if a bit off topic.

And for a sci-fi crossover, a Star Destroyer is the size of that Cobra Destroyer.

Oddly enough, Lucas was correct in calling them Destroyers, because that's the class of ship they qualify for

 Grey Templar wrote:
And for a sci-fi crossover, a Star Destroyer is the size of that Cobra Destroyer.

Oddly enough, Lucas was correct in calling them Destroyers, because that's the class of ship they qualify for

I give up, this thread is coming off topic and I'm not going to stop it.

When it comes to space battle crossovers 40k just wins...

Except against a couple somewhat obscure and well chosen opponents. Honor Harrington maybe, because their ships fight at realistic ranges (i.e. a light minute or so).

@dementedwombat - Yeah, I'm under no illusion that real-life tech is going to be half as awesome as 40K tech, but my posts were essentially all to the point that regardless of scale or aesthetics, the tech of 40K is either here now or possible in the near future. Also, aerospace engineer? That's got to be a fairly interesting job.

@Brokksamson - Awesome picture! Yeah I don't reckon we're gonna have any space vessels that size soon

Apologies to the OP, because it was probably me that prompted the OT debate, so more on topic:

Darthslowe wrote: the Imperium actually has the safest plasma technology in the galaxy. It's just the coolant systems get stripped out of the plasma guns to be used in other weapons.

I'm interested as to where you got that information. I'm not a veteran of 40K, only been into it for a year or two now, but I read a lot of the lore and from what I gather, due to the Imperium's fear of technology stemming from the 'Dark' Age of Technology, the Imperium has probably the most unstable or at least unreliable tech in the galaxy out of all the major races apart from the Orks. I would have thought that the Eldar or the Tau's plasma tech is far superior as they are constantly adapting and creating, rather that the reverse-engineering of the Imperium. Obviously, please correct me if I'm wrong, because your sources may be better than mine, but this is just what I've gleaned from various sources.

I believe he was being sarcastic.

Anyway, in the fluff, Imperial Plasma is safer than it is on the tabletop. And Gets Hot doesn't always represent the gun exploding. It can represent the guy getting burned to where he can't fight(not actually dead) or the gun deactivating for safety till it can be repaired by a techpriest.

Maybe heavy bolters can be made shorter (Basically a really bulky bolter) but they make em longer to look more intimidating/feel more powerful to the user?

Ahh, apologies then, didn't get the sarcasm there And, having consulted Lexicanum, which is probably where I got my initial information from, it says that the Imperium's models are prone to overheating and failure, but I'm guessing that they're mostly stable if handled well.

A little more on topic from me as well. As far as I know, Heavy Bolters/Bolters do not need cooling systems because there is no heat in the chamber, they are not actually firing a bullet in the traditional sense, every bolter round is actually like a tiny RPG, it has it's own propulsion jet.

As far as the aspect of ejection and cycling the weapon, Games Workshop has said that all bolters fire a .75 caliber caseless self propelled projectile... Caseless would mean there is nothing to eject. There is a lot of contradiction around this considering that GW often displays casings being ejected out the side of a bolter, so who knows if they actually understand what a caseless round is.

Yeah, any weapon can have problems if its used too much. Plasma is just a little more temperamental than most.

... also realize that all of these weapons were designed by the studio almost 30 years ago, where gyrojets, plasma, warp drives, hell, even the internet, was firmly in the realm of science-fiction to *most* people.

@Brokksamson - So I presume if GW states ALL types of botler are .75 calibre, then the Heavy Bolter is only 'Heavy' due to it's rate of fire? And yeah, if it's caseless ammo then there should be no need for an ejection mechanism, but considering that they show, at least on Sternguard bolters and storm bolters, the metallic rounds in the magazine, this may be old fluff?

@Psienesis - I hate to break it to you, but Plasma was first discovered in 1879 and the term first coined in 1928 - well before 40K. However, I'll totally agree with you that the average person would be clueless about it even in the '80's when 40K came out, the same going for warp drives and the internet etc (Less so the gyrojet, as those guns were aimed at the public). However, my initial comments were aimed at us, a modern audience, still in a state of disbelief that GW's tech is in anyway real, when we have so much evidence that it is.

 Brokksamson wrote:
A little more on topic from me as well. As far as I know, Heavy Bolters/Bolters do not need cooling systems because there is no heat in the chamber, they are not actually firing a bullet in the traditional sense, every bolter round is actually like a tiny RPG, it has it's own propulsion jet.

I think it's false to assume that there is absolutely no heat within the firing chamber. Using your comparison of an RPG, a booster charge is located at the base of the RPG rocket which is ignited to give it it's initial launch before the rocket motor ignites at a safe distance away from the operator. Rifle grenades aside, other methods of deployment include pressurized gas or mechanical launch, which limits the range possible. Given the range and bullet-like behavior of the bolter, I would guess that they combine both a traditional rifle firing pin/percussion cap launch (giving it decent accuracy, especially if rifled) with a jet rocket to give it increased range. If there are stabilizing fins on the bolt round, the rifling will give it the prerequisite spin to increase accuracy further.

I've fired 40mm AGLs before. Trust me when I say that their barrels get hot.


Automatically Appended Next Post:

 Warpig1815 wrote:
@Brokksamson - So I presume if GW states ALL types of botler are .75 calibre, then the Heavy Bolter is only 'Heavy' due to it's rate of fire? And yeah, if it's caseless ammo then there should be no need for an ejection mechanism, but considering that they show, at least on Sternguard bolters and storm bolters, the metallic rounds in the magazine, this may be old fluff?

I'm disinclined to believe that heavy bolters only differ in rate of fire, given that normal bolters (and bolt pistols) are 4/5, and heavy bolters are 5/4. GW has on some occasions, as previously mentioned, cited the bolter as being 1.00 caliber too. Also, whether rounds in the magazine are shown are irrelevant to whether the ammunition is caseless or not...

Humanity has also been aware of Quantum Physics for much longer than *most* people have been aware of the concept, but I don't expect t bunch of gamers sitting around a studio writing up rules for a game of pretendy-fun-time using plastic soldiers to be aware of the ins and outs of scientific academia, which is why things in 40K work the way they do.

You can make the same comparison to the RPG "Cyberpunk 2020", which was written in the late 80s and early 90s, and has your characters, in 2020, worrying about paying long-distance charges when connecting to "the Net" using your "cellular cybermodem" (30% chance of dropping the connection in a moving vehicle) on your attache-case sized laptop, and connecting their "smartguns" to their heads via a 1/4" coaxial cable and plug (rather than via Bluetooth or NFC, which is what we have now). The technology of the real world outpaced and outstripped the science of the fictional universe.

I think possibly what he meant was that they don't need convoluted heating systems such as heat syncs, water cooling or advance air-cooling, as the heat produced by the initial charge, whilst present, is not hugely significant to warrant cooling on the scale of machine guns such as the Vickers gun would use:



I mean to be fair, whilst we are debating what cooling system bolter weapons would need, this is just the assumption that there HAS to be a cooling system. For example, the modern day minigun has one of the fastest firing rates of modern weapons, and yet has no cooling method other than just the air around the barrels. Similarly, the MG42 of WW2, had no cooling method other than air around the barrel and it was firing 20 rounds a second. Which brings us in a full circle - if it isn't containing a cooling system, what does it contain?

 Warpig1815 wrote:
I think possibly what he meant was that they don't need convoluted heating systems such as heat syncs, water cooling or advance air-cooling, as the heat produced by the initial charge, whilst present, is not hugely significant to warrant cooling on the scale of machine guns such as the Vickers gun would use:



I mean to be fair, whilst we are debating what cooling system bolter weapons would need, this is just the assumption that there HAS to be a cooling system. For example, the modern day minigun has one of the fastest firing rates of modern weapons, and yet has no cooling method other than just the air around the barrels. Similarly, the MG42 of WW2, had no cooling method other than air around the barrel and it was firing 20 rounds a second. Which brings us in a full circle - if it isn't containing a cooling system, what does it contain?

I'm in agreement here. I don't know what else that bulk could contain. As we've ascertained that it's likely a firing pin-triggered launch, there could be space for the gas blowback and bolt mechanism, as well as the motors for the bolter's autoloader. It might also be an electronics package that meshes with their power armor's autosenses.

@Psienesis - I know that it's just a game and I certainly don't expect GW or anybody else to know the ins or outs of physics to be able to enjoy it. My point was merely that when people do think 'Bah, that's just GW rubbish!', they should probably think for a moment and say 'Is it?' and then google it, because it'll amaze you on the cool we're coming up with now that back then was considered just to be sci-fi nonsense. All my posts were just really to reinforce that point. However enough of that because it's OT. I refuse to be drawn further on the subject.

@Enigwolf - If we assume the bolter round is a small charge to propel it out the barrel and then further rocket charges to propel it to the target then, the 40K Wikia seems to think that the launch is induced by an electrical pulse. This, I have no fething idea on how it would work. Confusion!

40k Wikia is the least reliable of sources, for one. But then it could simply be that the percussion cap of the launch charge is triggered by an electrical pulse, not to dissimilar to how C4 and other plastic explosives are triggered by electric pulses (Yeah, you can't blow C4 up by shooting at it).

The resultant gas blowback could feed back into and power a small generator which charges a battery pack for the electrically-induced pulse. Going by this system, we now have the following subassemblies:
Autoloader motor
Electrically-induced pulse firing mechanism
Gas generator
Battery pack, connected to Autoloader motor, firing mechanism, and gas generator
Gas blowback/rifle bolt mechanism
Onboard electronics package

Given that subassemblies like the motor and the generator are pretty sizable systems, it wouldn't be unrealistic to assume that these parts are contained within the rear of the bolter. A small motor without enough torque won't reliably load bolt rounds without constantly jamming (since it's direct feed as opposed to gravity fed, much like an airbrush). A small generator won't generate enough to store in a battery to create the pulse, and a small battery won't hold much charge, as it should be safe to assume that the pulse required is a significantly large one to prevent misfires and bolt rounds going off in a high-statically charged environment.

There, I think I theory-hammered the bolter from an engineering perspective of how I would build one.

Yeah, I know about the 40K Wikia frm first hand experience. Getting into 40K I made the mistake of reading that over the worse looking Lexicanum, until it was pointed out to me that Lexicanum is far more accurate.

Your theory sounds about right actually, the only thing it's missing is probably all the hardware for auto-sense uplinks and interfaces for the power armour such as genetic palm sensors that some bolters contain. Assuming a cooling system is also present (Depending on the build-up of heat from the initial charge), there's quite a fair amount of mechanisms within the casing of bolters in general.

I think therefore that collectively, after many OT debates, this thread has just answered the OP's question!

I think it's fair to assume that there isn't a need for an active cooling system in a bolter. Well, if it uses cased ammunition, the case actually carries a lot of heat out with it. But the reason I say that is because the initial propellant charge required is only needed to kick it out of the barrel, not three hundred yards downrange. So it potentially might use a smaller gunpowder cartridge than a bullet, and thus even less heat generated. Although as previously mentioned, the entire damn bolter itself could act as a heatsink.