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Boltguns are IMHO definatly designed to be Ork killers. it's worth noting that about the time Marines would have been adopting the boltgun the great crusade was focusing on defeating a massive ork empire.

Not sure how much the fluff has changed since 3rd edition, but:

Bolter rounds were described as .75 caliber gyrojet mass-reactive explosive rounds(sometimes caseless).

Everything in the description has some real world basis:

Gyrojet rounds did exist but with some issues. With a small case and enough powder to ensure the round clears the barrel with enough force to damage/kill at point blank, bolter rounds could be better variants in this regard.

.75 caliber is fairly close to 20mm, with the explosive and mass reactive aspects(which I will address separately), they are basically just high explosive armor piercing (HEAP)autocannon rounds.

The "mass reactive" descriptor was, at the time, often misunderstood. This is just a short-hand way of saying impact-trigger delayed fuse.

So putting all this together, the point of the round is to have a fairly stable-trajectory, constant-velocity projectile that is set to explode while still inside the target, before it has a chance to exit. In one of the early HH novels, the marines are on a planet infected with a Nurgle zombie plague and mention that they a glad they brought sub-sonic rounds instead of AP ones; since the AP rounds would have just pass right through the zombies.

Worth noting that Caliban had primitive power armour and boltpistols before the Imperium arrived. It was the survival of these technologies while most everything else regressed to a medieval level that allowed them to fight the monsters and led to the knightly orders.

IMO bolt weapons therefore predate the age of strife and probably were designed to take down orks or human supersoldiers of the time.

well very little technology from the great crusade likely didn't pre-date the age of strife. and I suspect the bulk of it was astartes implants.

It's like a bunker buster bomb, but a bullet, and for people...


Automatically Appended Next Post:
The one issue I have with bolts is that they would need a safety distance before arming (like a modern 40mm) to negate risk to the firer..yet this is never mentioned, in fact it doesn't seem to exist... Examples in the stories of point blank rounds exploding in people's heads etc.

 queen_annes_revenge wrote:


Automatically Appended Next Post:
The one issue I have with bolts is that they would need a safety distance before arming (like a modern 40mm) to negate risk to the firer..yet this is never mentioned, in fact it doesn't seem to exist... Examples in the stories of point blank rounds exploding in people's heads etc.

Probably for 2 reasons.
1 Space Marines in power armour would likely not be too bothered by the explosion in close proximity as its not that much shrapnel anyway.
2 Grimdark.

 Kcalehc wrote:

 queen_annes_revenge wrote:


Automatically Appended Next Post:
The one issue I have with bolts is that they would need a safety distance before arming (like a modern 40mm) to negate risk to the firer..yet this is never mentioned, in fact it doesn't seem to exist... Examples in the stories of point blank rounds exploding in people's heads etc.

Probably for 2 reasons.
1 Space Marines in power armour would likely not be too bothered by the explosion in close proximity as its not that much shrapnel anyway.
2 Grimdark.

by "grimdark" he means "what you think the IoM cares if the firer is hurt?"
and he's got a point.. see plasma weaponry

It's pretty common to see a plasma pistol held by a cybernetic limb.

I built an Astartes Lt. with a left arm & leg replacement limb just to show the dangers of overcharging. but he's still armed(get it) with one since it has come in handy more than once.

Singleton Mosby wrote:Having read 'Rynn's world' (and not really liked it) I kept wondering time and again about the description of bolter shells.

So, aparently a bolter shell embeds itself in its target and then......after a second, explodes. What exatly is the use for that? I you want to punch through something you use hardened AP rounds, if you want maximum carnage you use hollow point or something (I am no expert at all). Why use a shell which has only a bit of the penetrating power and a lot of explosive power, but with a delay? Is the intended effect something like a shaped charge perhaps? But what good does that do against flmsy targets like guardsmen etc.

And then, is there some sort of real world equivalent which does about the same?

Looks like most of this was covered by others, but I'd like to address one thing: you have my condolences for reading Rynn's World, and this comes from someone who's been a fan of Crimson Fists since Rogue Trader.

Folks other than marines use bolt weapons though... Also you'd need some inertia based arming safety to stop accidental detonation in the breech, and possible subsequent sympathetic detonation of the rest of the shells in the magazine.

 Just Tony wrote:

Singleton Mosby wrote:Having read 'Rynn's world' (and not really liked it) I kept wondering time and again about the description of bolter shells.

So, aparently a bolter shell embeds itself in its target and then......after a second, explodes. What exatly is the use for that? I you want to punch through something you use hardened AP rounds, if you want maximum carnage you use hollow point or something (I am no expert at all). Why use a shell which has only a bit of the penetrating power and a lot of explosive power, but with a delay? Is the intended effect something like a shaped charge perhaps? But what good does that do against flmsy targets like guardsmen etc.

And then, is there some sort of real world equivalent which does about the same?

Looks like most of this was covered by others, but I'd like to address one thing: you have my condolences for reading Rynn's World, and this comes from someone who's been a fan of Crimson Fists since Rogue Trader.

eh I've read worse BL novels..

queen_annes_revenge wrote:It's like a bunker buster bomb, but a bullet, and for people...


Automatically Appended Next Post:
The one issue I have with bolts is that they would need a safety distance before arming (like a modern 40mm) to negate risk to the firer..yet this is never mentioned, in fact it doesn't seem to exist... Examples in the stories of point blank rounds exploding in people's heads etc.

queen_annes_revenge wrote:Folks other than marines use bolt weapons though... Also you'd need some inertia based arming safety to stop accidental detonation in the breech, and possible subsequent sympathetic detonation of the rest of the shells in the magazine.

You read my mind! Here’s a video to show the usefulness of delayed fuze, albeit on a much larger scale

[youtube] https://youtu.be/rMTcViSApgI[/youtube]

Sympathetic detonation is a worry, but i guess they either have clever electronic safe arming fuzes or (much more grimdark) rely on the mitigation of armour/expendability of soldiers/limbs to justify the safety case(not very grimdark I know!)

 queen_annes_revenge wrote:
Folks other than marines use bolt weapons though... Also you'd need some inertia based arming safety to stop accidental detonation in the breech, and possible subsequent sympathetic detonation of the rest of the shells in the magazine.

I'm fairly certain that bolt weapons are stated to be quite rare amidst the guard. And that, while they're valued for their power, they're extremely finnicky weapons and prone to jamming / blockages / detonation. So.. Reward, but with a risk.

The Sisters probably have better quality / better maintained bolters. They're better trained, better equipped, less expendable, and all around more elite / held to more rigorous standards than the Guard. Plus they wear power armor, so a shell exploding point blank is probably negligibly dangerous for them.

Yeah I guess, but even wearing armour I think any professional fighting force wouldn't want to risk potentially damaging their soldiers or equipment. Using grimdark to explain it doesn't really cut it as the concept is just a little stupid.

Its easy enough to explain. the rounds are armour piercing, and after say, 50m of flight a secondary internal bursting charge is armed. anyone hit before that is still going to be deaded by the AP effect.

Yeah, the Sororitas have a specific pattern of bolt gun, the Godwyn-Daez.

As far as I remember its specific to them and mechanically different to the Astartes version. Something about them being more expensive since they have to work with Sororitas power armour.

 Singleton Mosby wrote:
Having read 'Rynn's world' (and not really liked it) I kept wondering time and again about the description of bolter shells.

So, aparently a bolter shell embeds itself in its target and then......after a second, explodes. What exatly is the use for that? I you want to punch through something you use hardened AP rounds, if you want maximum carnage you use hollow point or something (I am no expert at all). Why use a shell which has only a bit of the penetrating power and a lot of explosive power, but with a delay? Is the intended effect something like a shaped charge perhaps? But what good does that do against flmsy targets like guardsmen etc.

And then, is there some sort of real world equivalent which does about the same?

The point is to explode inside the target for maximum damage. This is the same principle that battleship shells in ww2 used. They were an armor piercing shell that had a warhead that exploded after penetration.

What this does against fleshy things is horrendous wounds. Useful for terror but also useful against particularly resilient targets. It’s overkill against guardsmen, but it’s useful against Nids, orks, etc...

It was the cheaper alternative to arming all of the Legions with Volkite weapons, and still did the job!

 Grey Templar wrote:

 Singleton Mosby wrote:
Having read 'Rynn's world' (and not really liked it) I kept wondering time and again about the description of bolter shells.

So, aparently a bolter shell embeds itself in its target and then......after a second, explodes. What exatly is the use for that? I you want to punch through something you use hardened AP rounds, if you want maximum carnage you use hollow point or something (I am no expert at all). Why use a shell which has only a bit of the penetrating power and a lot of explosive power, but with a delay? Is the intended effect something like a shaped charge perhaps? But what good does that do against flmsy targets like guardsmen etc.

And then, is there some sort of real world equivalent which does about the same?

The point is to explode inside the target for maximum damage. This is the same principle that battleship shells in ww2 used. They were an armor piercing shell that had a warhead that exploded after penetration.

What this does against fleshy things is horrendous wounds. Useful for terror but also useful against particularly resilient targets. It’s overkill against guardsmen, but it’s useful against Nids, orks, etc...

Bolt rounds definately detonate closer than 50m. Its how

Yeah but you wouldn't need explosive bolts for that. The effect of such massive calibre armour piercing rounds fired point blank would do that anyway. And high explosives detonating that close just doesn't make sense, even if you say we'll he's in power armour blah blah.

the pressure from the bolt leaving the barrel into a cavity would do the job just fine.

It would make sense that the fuse is armed as soon as it leaves the barrel as to allow close range detonation. Shooting the MK19
Automatic Grenade Launcher (which uses hotter 40mm vs m203 40mm) you can basically watch them leaving the barrel. so a bolt isnt necessarily going "fast" when initially launched. It has plenty of kinetic energy at that range to not need the boost from the rocket motor to penetrate and explode. Now factor in the rockets additional range and velocity, it should maintain that level of inertia across its operating envelope.

Yeah but that's the issue. If we say the firing sequence is ballistic (low explosive propellant) followed by rocket assisted (low explosive rocket motor) then the high explosive secondary charge would have to be armed last otherwise the other stages could cause detonation. The rocket assist would have to kick in after it had cleared a suitable distance from the barrel itself anyway. Its just another of those things that's they try to explain but don't end up doing a good job of clearing up.

My head Canon is that any shots fired at close or point blank range only act the same as regular rounds, and dont rocket assist or expose.

You can also tell that the design of the bolt gun is not just for shooting.

Most modern guns have very minimal casing for weight reduction.

If you stripped back a bolter there'd be a lot less gun.

IMO as current bolter design comes from the great Crusade specifically for space marines, it is also armoured.

They carry it across their chests - their armoured like a tank chests.

It would be silly for their guns to be more breakable than themselves.

So the design is over the top armoured making it awkward for non powered armour dudes to use.

Really? I think if anything bolters need to be bigger. The new primaris bolt rifles are definitely more realistic in terms of length. Although if your shells are rocket assisted then I guess you wouldn't really need a longer barrel.

But then the shells are . 75 calibre so the weapons are going to be larger and chunkier.


Automatically Appended Next Post:

 Kommissar Kel wrote:


Gyrojet rounds did exist but with some issues. With a small case and enough powder to ensure the round clears the barrel with enough force to damage/kill at point blank, bolter rounds could be better variants in this regard.


So putting all this together, the point of the round is to have a fairly stable-trajectory, constant-velocity projectile that is set to explode while still inside the target, before it has a chance to exit. In one of the early HH novels, the marines are on a planet infected with a Nurgle zombie plague and mention that they a glad they brought sub-sonic rounds instead of AP ones; since the AP rounds would have just pass right through the zombies.

Gyrojet stabilised would make sense. Sort of like a miniature scale Chinese 107mm rocket.

Them having different types of ammunition would also make sense. We have different ammo types now so I'm fairly sure they should.

Hellebore wrote:
You can also tell that the design of the bolt gun is not just for shooting.

Most modern guns have very minimal casing for weight reduction.

If you stripped back a bolter there'd be a lot less gun.

IMO as current bolter design comes from the great Crusade specifically for space marines, it is also armoured.

They carry it across their chests - their armoured like a tank chests.

It would be silly for their guns to be more breakable than themselves.

So the design is over the top armoured making it awkward for non powered armour dudes to use.

My headcanon also says astartes bolter casing is armour - note that they often fire from the hip- holding the bolter across their navel. This area is less armoured than the chest- flexible as it needs to be.
Holding another armour plate across your abs to shield a vulnerable area seems like a smart move.

The real world equivalent of a bolter shell is an anti tank rocket.

It has an armour piercing tip to defeat the enemy tank's armour and then a shaped charge that explodes forwards, filling the enemy tank with shrapnel or molten metal.

Nowhere in the lore does it mention bolter shells having shaped charges, at least nothing I've read states so. Now depending on how thick SM armour actually is a shaped charge could be useful, however, considering the rocket propellant, the addition of a shaped charge would likely cause space issues due to the explosive charge, the copper cone and the standoff space in the projectile.


Also, HEAT charges don't have armour piercing tips. The molten jet formed by the implosion of the copper cone (munroe effect) is what pierces the armour. Your description seems to combine the properties of sabot, HEAT and HESH, which all have different effects.

 queen_annes_revenge wrote:
Nowhere in the lore does it mention bolter shells having shaped charges, at least nothing I've read states so.

Shaped charges are widely misunderstood. People think it just means any explosive that is meant to penetrate armor. A shaped charge is a projectile that is tipped by an inverted cone of metal(usually copper) which has an explosive packed around it. When the explosive detonates, the inverted cone forms into a jet of molten metal that punches through armor. Look up the bajillion videos on youtube.

If someone was to make a bolter shell today, the projectile itself would be a lot like a miniature GBU-57A/B Massive Ordnance Penetrator. https://en.wikipedia.org/wiki/Massive_Ordnance_Penetrator

A missile which is designed to penetrate through tough layers of armor and then explode.

Bolter ammo would be a lot like this ammunition.

https://www.youtube.com/watch?v=AXaaybiRiYY

Essentially it hits the target, and then a short amount of time later the charge explodes. This gives the round time to embed within the target so you get maximum payoff of the explosive charge.

Did you read the rest of my post? I understand the operation and definition of a shaped charge. That's what I'm saying, do you think you could pack all the other elements into a bullet? Because even once you've got the copper cone, you also need a stand off space (you know the cones on the front of an rpg? They're empty spaces which allow the munroe effect to take place when they hit a target.)


The bomb you mentioned is a totally different concept. It uses a hardened nose plus aerodynamically forced spin to penetrate the concrete. This is more feasible for a bolter round.

Well, there's 39,000,000 years of technological advancement between now and 40k. So I'm guessing restrictions we experience as easily bypassed by then.

Consider the advancement of guns over history. From using blackpowder to shoot steel bolts at people, via rifling to today's most modern dakka. Lots of refinements, making them ever more deadly and accurate.

As others have said - they're terror weapons. They don't wound. They kill. And in a spectacularly gory fashion. It's one thing to see a comrade bleed out from say, a gut shot. It's quite another to see them turn into a fine red mist from the waist up, leaving bits of bone embedded in you like shrapnel.

Aye but if you apply that logic most of the tech in 40k shouldn't exist as it does...