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So, a time delay secondary charge, meaning that provided it had impacted on something, the secondary charge would detonate regardless of whether it had penetrated an object or not, so not 'really mass reactive?'

Welcome to today's seminar: "Dealing With Science Fiction Authors Talking About Subjects They Aren't Experts In".

With open bar.

I cant remember where I got it from, but to me mass reactive means that the warhead explodes if the shell gets close enough to any significant mass. This could be because the shell has buried itself into a target, or if it gets close enough to something else. Given that modern inertia sensors can be extremely small I can imagine magical future tech being small enough to fit easily in a small calibre round.

6ou dont need any time delay for such a thing, although it means that you can never do a ricochet shot without even more complicated electronics. However given the size of a bolter I can also see it doing an OICW style programming of every round in order to prime the mass reaction detonation system just at the right distance from the target.

Addendum... seems like I got the idea from 2nd ed wargear book

My mistake... the proximity detonation version is a different munitions, as of 3rd ed rulebook with metal storm frag shells.

I like how those illustrations make the bore seem even larger than on the models.

Again, if this were to be effective, I can't see a stubby little shell like that doing it. Rockets are sort of long for a reason, on second thought that looks more like a Carl-G (or similar recoil-less rifle) shell than a rocket. These image show clearly that the bolter has a propellant casing that are shown as seporate to the projectile so it is conventionally ballistic to a degree, if you are playing what you see is what you get lore wise.


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BTw i wonder what qualifies as a sudden increase in local area mass? If some Necron used a mcguffin to increase local gravity would marines find their ammo cooking off? If you dropped a live bolt round would it explode?


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But my point also continues, there is no reason to have a hybrid rocket/conventional ballistic weapon unless you are wanting to kill armoured foes at very long range. With great precision. This would actually be a more suitable use of space marines, because when you're in the middle of everything mixing it up you are not as effective(you have a smaller impact on a smaller part of the battlefield, and its much easier for the enemy to call a little something like a heavy artillery box barrage on you. Which would see you and any rescue efforts turned to scrap).


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Bolter shouldn't compare to conventional infantry weapons (at least an astartes bolter in my view anyway( yes i'd support the added complication of buffing all astrates weapons in strength to represent that they are beefed up weapons this would be a race wide buff so it would not be hard to implement (becasue why else would you beef up marines and pt them in power armour?)) I compare the bolter to the heavy stubber: m2 browning, browning 30cal, or forgeworld's MG42(even listed in lore of the war on Vracks as being an identical cartridge to the German WW2 8mm) and in comparison it is not great. It's an assault weapon you'd expect to put out the lead, but a bloody kelemorph puts out more lead with his revolvers. Hell in the right circumstances russ puts out more rounds with it's frikin howitzer(battle cannon). And well, that says a lot about the bolter's performance.

Gyrojets exist and they got up to mach 1. The burn lasted for a second or so according to the wiki, but that was a 13mm long 0.51 cal rocket.

https://en.m.wikipedia.org/wiki/Gyrojet

75 cal bolt rounds are bigger and and longer, giving it more burn time and room for the explosive


Couple that with the explosive round available for shotguns:

https://m.youtube.com/watch?v=WV379084djs

And you got bolt rounds.

The advantages (in being light and low recoil) a gyrojet offers are not really applicable to a a marine. Also it does not do the damage you'd want to if you were taking advantage of this style platform. A marine is a really big toughffin in power armour, it does not care about recoil or having a lighter weapon. A lighter weapon just makes a crappier club when you need to use it as one. A marine is engaging threats either far away(battlefield) or point blank (breaching in a ship ie living up to their actual name) a rocket proppelled projectile is unsuited to this later task. It would make more sense for it to be a hybrid.

I can't get over how ridiculous "depleted deuterium" is. Deuterium isn't an element, it's an isotope of hydrogen.

What does "depleted" even mean when you're talking about a given isotope? For uranium, "depleted" means the radioactive isotopes have been removed, leaving only the stable ones. For hydrogen, the radioactive isotopes are already ridiculously rare, why would you deplete it of anything?
And pure deuterium, in normal conditions, is a gas. How/why would you make the core of anything out of a gas? A gas with a density close to that of helium, too... I mean, if it's meant to act as an explosive, there are plenty of better ones. Deuterium is useful in some nuclear reactions, but I don't think anyone has ever claimed that bolters were miniature H-bombs, right?

Anyway, we know the writers at GW aren't scientists. It's really better to ignore the details or you'd spend all your time pointing how dumb everything is in 40k. Bolts work the way they're supposed to because it's cool and that's that.

And lasgun power is measured in megathules... I would tend to ignore the naming conventions to a certain extent

In terms of cooking ammo off, I imagine that the detonator.only.gets.primed when the round is fired. I guess you could try to.create.a localised gravity field.next to the bolter.muzzle, but if you are doing that then the bolt rounds aren't going to hit anything anyway regardless of whether they detonate or not.

A fin stablised missileette would also suit the name bolt. As it would look (at least a bit) like an actual crossbow bolt, which would make the inquisition's crossbow style bolters make at least a little sense.


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It would also be badass.

 Melissia wrote:
Welcome to today's seminar: "Dealing With Science Fiction Authors Talking About Subjects They Aren't Experts In".

With open bar.

I find it's best to shrug, cite Clark's Third law and not think too hard about things like this.

Alternatively I find it an interesting thought exercise to take the core parts of something and use logic to make it work and estimate it's power, measured against what we currently have and know about.
Although that might be because I write about stuff, and I hold that if I do not understand things I'm writing about (or don't make an effort to, or that it does not stand up to a short interrigation of logical thought) it's not worth writing about.


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Obviously it is better to make it work in the simplest way possible. This is my line of logic, you can pick it apart if you want.

Hence bolter has casings-> ballistic. Don't care what they say, evidence seen with my own eyes. is gyrojet as well-> hybrid ballistic and rocket-> Advantages over ballistic or rocket by themselves? Yes, a few disadvantages few in comparison to what it brings to the table.

Big calibre -> Explosive payload and explosive form of penetration? yes likely. -> big calibre kinetic penetration inefficient, excessive drag.

Gyrojets/rocket bullets unfortunately never went anywhere for a reason, and it's because they can't hit the broad side of a barn. When a bullet leaves the barrel, it's going as fast as it's gonna go already, and any environmental impact such as wind is going to have comparatively little time to act on the projectile. The Gyrojet isn't even lethal for some time out of the barrel, doesn't reach peak acceleration for a couple of meters, and then because it was so slow and everything has so much time to act on the projectile, that you can miss vehicle sized targets at a hundred meters.

The problem with hybrid concepts the way 40k often likes to portray bolters, with a classic primer ignited initial stage taken over by the rocket, is that it would still suffer from this problem (not a acutely, but still badly) and if you're already going with a conventional initial stage, why bother with the rocket second stage? It adds no value, just beef up the initial stage a bit, drop the rocket engine, and get more payload, better accuracy, and substantially less complexity. Unless the projectiles are going to be self guided, there's no purpose to an on board propulsion system.

To be fair, I doubt there's been a ton of R&D put into that kind of small rocket projectiles, while traditional firearms have existed for more than a thousand years. And the first ones were pretty awful too...

The advantages of the gyrojet were that the weapons were really light (since they were basically just a launch tube) and had very little recoil. So, in theory, you could make the projectiles be pretty big and heavy without having to worry about the user breaking their shoulder when firing. Going as far as "soda can bolts" is still dumb (because you want to be able to carry more than a dozen at a time), but that leaves room to shoot much more than a simple solid bullet.

Now since we're into sci-fi territory, the major advantage a rocket has over a bullet is the possibility to control its trajectory in flight: theoretically, you could have a smart projectile that compensates for both gravity and wind to have an almost perfectly straight trajectory. Space marine bolts don't seem to do that, though, so it's kind of a missed opportunity

They came up with the bolter originally because the writers wanted a really noisy terror weapon and it was the 1980s and bipropellant ammo sounded super awesome. This thing will go BANG RAAAAARK BOOM with every round. Effectiveness on the battlefield can be hand waved away with futuronium based materials and targetting/guidance technology.

Is it possible to make a bolter with modern technology? Definately. Would we want to? Not really as the modern military has no requirement for such a weapon. Too hard and expensive for too little additional effectiveness over standard bullets.

Yep, given the era, the future was "caseless" and "gyrojet", etc. etc. Typical madness in the 80's sci-fi world.

The reality is, from what we see in games and art, it's simply a 20-35mm sized carbine, with normal cases, firing a normal shell. They could easily fix this in the fluff and simply have innumerable versions, variants and patterns of bolt guns of course. Likewise, ammunition could vary. It's as simple as "During the Horus Heresy, caseless ammunition was difficult to produce and acquire, so manufactorums began designing a simpler cased cartridge, using bla bla bla...."

There are far greater sins of weapon design in the 40K universe/models/lore...you need only look so far as the gas operated(?) bolt action sniper rifle for the Necromunda fellas...where the bolt itself is captured inside the receiver and cannot be operated...etc.

 Vaktathi wrote:
Gyrojets/rocket bullets unfortunately never went anywhere for a reason, and it's because they can't hit the broad side of a barn. When a bullet leaves the barrel, it's going as fast as it's gonna go already, and any environmental impact such as wind is going to have comparatively little time to act on the projectile. The Gyrojet isn't even lethal for some time out of the barrel, doesn't reach peak acceleration for a couple of meters, and then because it was so slow and everything has so much time to act on the projectile, that you can miss vehicle sized targets at a hundred meters.

The problem with hybrid concepts the way 40k often likes to portray bolters, with a classic primer ignited initial stage taken over by the rocket, is that it would still suffer from this problem (not a acutely, but still badly) and if you're already going with a conventional initial stage, why bother with the rocket second stage? It adds no value, just beef up the initial stage a bit, drop the rocket engine, and get more payload, better accuracy, and substantially less complexity. Unless the projectiles are going to be self guided, there's no purpose to an on board propulsion system.

Unless you want to kill armoured enemies (astartes) at several kilometres. Also guided ammo would be badass. That was my interpretation of the reason to have a hybrid. But as the bolter is describd as an assault weapon suitable for close range engagments I'd have to agree to drop the rocket motor in this circumstance.

It could be argued it is to counter recoil in space, but the bulk of an armoured marine with mag-clamped boots on a firm surface. Well recoil is again looking like a non-issue.

Something to consider is the propellant could also be part of the explosive.

The closer the target, the more propellant remaining to add to the explosion.

If you have a high explosive bursting charge, any effects from additional left over rocket fuel are going to be pretty negligible.

Probably best mordern day equivalent would be a automatic cannon IMO.

25MM Cannon fired from the US Bradley is a good example.

Hellebore wrote:
Something to consider is the propellant could also be part of the explosive.

The closer the target, the more propellant remaining to add to the explosion.

Generally you want propellent to be a slower burning more constant push. Explosives you want as quick a burn as you can get. Not to say you can’t use different kinds for the same job, or what the properties space magic chemistry can produce. Unused propellent can definitely splash around and burn, but more as fallout then extra bang.

I'd love to see what the gw designers envisioned the working parts and operating system to be on those bolters more than the bolts themselves... I know there are some diagrams, but jeez... Is it gas operated? I cant see it being blowback or recoil.

its probably a combo of delayed blowback & gas

Given the size of the thing it could just be electrically operated.


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In fact the cutaway diagram of the storm bolter I posted above has a piezo-electric ignition chamber, and a blast vent directly above the chamber, which would suggest it is electrically fired with no real use for the waste gas. Ejection can be through either side and is selectable so even that could be electrically driven.

Might come in handy in the void, you'd want to shield it quite well to stop it getting EMPed. Should have a wind up lever on the side, for extended ops.

Or like, plug it into the plasma reactor on your back

 catbarf wrote:
Bolters are canonically 0.75-cal, which is very close to 20mm.

And have a 30 round magazine?

This coming at the time when the LRBT was determined to have a 120mm cannon - the barrel muzzle is significantly bigger than a Guardsman's whole head...

None of Matt Ward's scales make sense... The 'characteristics lore' introduced around that time tried to apply relativistic values to 40k to bring in an appeal to the military junkies...

LRBT would have a barrel closer to 203mm or 280mm...
A Bolter would have a magazine of 10-16 rounds - actually the old game, Fire Warrior made possibly the best representation of the Bolter seen... ever!
The individual bolts seem more reminiscent of a 2lb pompom at least in the old 3E lore...

Now quantify a real life equivalent using the 0.75" scale with the following:
Heavy Bolter
Autocannon
Battle Cannon
Earthshaker Cannon
Aquila Macro Cannon

And back on topic - the Bolt shells seem more akin to shaped charge projectiles - RPG's HEAT (High Explosive Anti-Tank) or HESH (High Explosive Squash-Head)

Looking up those and finding live-fire demonstrations brings out a plethora of articles ranging from the 1940's to now.

LRBT was just copied specifications of an M1 Abrams. But I wouldn't tank the model as being accurate. Not just because it's called 'heroic' scaling but because the model lack any kind of suspension, and of course the turret is too small to fit any kind of weapon breach. Let alone recoil systems. Unless it is armed with a water pipe and they convinced enough(captive I guess) orks it's a working cannon. That is what I'd do, and convince them it's a smooth ride.

I don't think a bolter would be 40mm. I know what you're saying with the firewarrior cut scene and the 2ib pom pom, but 40mm is getting to a realm where it should be combating enemies much more effectively than portrayed. If it's firing a HEAT warhead it should in that case be basically a krak grenade with 24' range and rapid fire.

I'd agree a HEAT round would be more suitable than the deterium capped impact fuse APHE shell that they seemed to push.

LOL I actually thought that those studs you sometimes see on marine armour was a type of ERA. It would also stop people hitting them with missile launchers from across the board...


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 Flinty wrote:
Or like, plug it into the plasma reactor on your back

Mowing down a heap of cultisits, plug comes out..."What's wrong Brother Gaius? Do you have a missfire?"
"God emperor damn them to hell! it's the vacuum cleaner situation all over again."