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Lots. The backpack-feed for the Heavy Bolter could conceivably carry 500-1000 rounds. The Marines's PA does all the heavy lifting, requiring minimal effort on the Marine's part.

Yes, you would (theoretically) empty it fairly quickly in a protracted battle... but that is specifically *not* what SM are designed for. They're shock troops.... get in, hit really hard, get the feth out. Fire it in short, controlled bursts and you're pretty good to go with blasting soft targets and light vehicles to pieces without blowing your wad in a couple seconds.

Other SM carry spare clips for their boltguns on their PA. The clips have a magnetic strip on each side, they just slap 'em wherever.

Yep, Marines are not suited for protracted battles. That's what the Guard is for.

Marines are there to hit as hard as inhumanely possible, and then fade away to strike the next target.

 Melissia wrote:
Yep, Marines are not suited for protracted battles. That's what the Guard is for.

Marines are there to hit as hard as inhumanely possible, and then fade away to strike the next target.

Exactly. Most of what marines can do is just for show - to demoralise the enemy sa well as destroy them.
Hence rocket propelled explosive rounds.
And being fething huge.
With giant guns.
etc.

Selym wrote:

 Melissia wrote:
Yep, Marines are not suited for protracted battles. That's what the Guard is for.

Marines are there to hit as hard as inhumanely possible, and then fade away to strike the next target.

Exactly. Most of what marines can do is just for show - to demoralise the enemy sa well as destroy them.
Hence rocket propelled explosive rounds.
And being fething huge.
With giant guns.
etc.

if it were all for show I don't think it would be as effective

Their effectiveness is part of the show.

They're called Shock Tactics for a reason. You hit hard, take out something important, and leave the enemy demoralised, confused and weakened.

Space Marines were meant to operate like a regular army with supply lines and so on. It was only after the Heresy that Guilliman's codex re-wrote their playbook to make the most of their smaller numbers and the reduced production capacity of the AdMech. Preheresy, there were two whole forges purely dedicated to making ammunition for the Astartes, let alone their other wargear. One of them belonged to the Fabricator Locum, the second most powerful adept in the Mechanicum.

After the Dark Mechanicum took Mars, the Marines had to adapt, conserve what resources they had. They halved their squad sized, reorganised their forces and we ended up with the Space Marines as we see them today: Elite shock-troopers who use fear and showmanship as a weapon.

And yet, still are able to hold out in protracted engagements

They aren't very good at it though. They run out of ammo or get overwhelmed.

Brothers of the Snake has a great example of what happens if Marines get in over their heads and get caught in a slugging match.

Or make it work one way or the other.

Tethgar wrote:
Or make it work one way or the other.

Nah, Marines just aren't as good at holding the line as Imperial Guard.

Yeah - of course the Marines will prove to be more resilient even in a prolonged defensive scenario due to the various small edges and advantages they have over other troops (power armor vs flak alone is a notable difference), but that's just not where they are capable of playing fully to their strength.
The Third War for Armageddon, for example, sees most Astartes withdraw as the Season of Fire starts, simply because they are robbed of their most important advantage: mobility.

Space Marines still get thrown into the defense of strategically important sectors again and again for the same reason (mobility = no-one else can deploy to the hotspot as fast as them), but that's just a temporary solution - as soon as the enemy turns their full strength towards them, they will be in trouble. For the big battles, you need the IG.

In other words: The Astartes focus on bringing down incredible amounts of pressure upon an enemy unprepared for them, overwhelming them quickly and preventing them from adapting to their tactics. Compared to the Imperial Guard which is capable of bringing even more pressure, yet lacks the mobility to truly exploit enemy weaknesses. It is very situational which force would fare better, hence they work best when being combined, with the Space Marines in a supporting role that punches holes into enemy defenses that are then filled by waves upon waves of Guardsmen and tanks following in their wake.

That is where they thrive, yet by its very nature this effect can be more reliably invoked in an assault scenario, seeing that defenders are always bound to the place they defend and thus lack the ability to reposition their forces and/or launch hit-and-run attacks. All they can do is to try and hold out as long as possible, hoping for reinforcements to arrive. Here it the attacker who will steadily crank up the pressure.

Or at least that's what I read in the fluff.

I still dont buy the rocket propelled theory that some fluff artists have put forth,

bullets are normally fired at speeds in excess of the speed of sound,

if you fire a conventional bullet, at this speed, then add rocket propulsion, it wont speed it up at all,

even if it did, it would destabilize the projectile when the sudden accelaration kicked in,

not to mention mercury switches activate on change in momentum, ie fast start or fast stop, so the round now needs two switches to go at different times, once on the rocket acceleration, once on the decelleration due to hitting the target.

none of the fluff has smoke trails coming off the rounds either, and I read far more fluf that treats the rounds as conventional.


as for extra ammo, even a 1" shell could easily be carried in quantity, esp for a large SM,

as an unmodified human, I can carry 200+ .77" rounds, and the only technology I need is a bandolier,

I do think it silly that most people dont attach the extra clips however, models shoot better with more ammo!

Tethgar wrote:

Selym wrote:

 Melissia wrote:
Yep, Marines are not suited for protracted battles. That's what the Guard is for.

Marines are there to hit as hard as inhumanely possible, and then fade away to strike the next target.

Exactly. Most of what marines can do is just for show - to demoralise the enemy sa well as destroy them.
Hence rocket propelled explosive rounds.
And being fething huge.
With giant guns.
etc.

if it were all for show I don't think it would be as effective

I mean that they added bits for show, without reducing effectiveness. In some ways, a less bulky marine could be just as effective as a bulky one, but bulky is scarier.
They could have all just been equipped with a bolter that did roughly the same abmout of damage, but was a lot less messy, or was fired like a normal round (but rocket-propelled shells are noisier, and make more light/smoke etc).
Ever looked at an MG42 or similar? Pretty damn powerful rounds fly outta that thing, and it is nowhere near the size of a marine's guns (Heck, they're almost as big as a normal 'umie!).

Long story short, when the Emprah said shock troops, he wasn't kidding.

easysauce wrote:bullets are normally fired at speeds in excess of the speed of sound,
if you fire a conventional bullet, at this speed, then add rocket propulsion, it wont speed it up at all

Well, at least in GW fluff, bolter rounds leave the barrel "at low velocity" before the rocket motor kicks in. And at least Stalker bolts are "sub-sonic".

easysauce wrote:even if it did, it would destabilize the projectile when the sudden accelaration kicked in

This may just be a case of sci-fi futuretech being fine-tuned sufficiently to prevent drastic changes. However, the 2E Wargear book does say that bolter accuracy really sucks at long range - it's a short range weapon, and the rocket motor isn't there to let the projectile fly further but just to crash into the target with added kinetic force. So in a way, you're spot on, but the gun is still working as intended.

easysauce wrote:not to mention mercury switches activate on change in momentum, ie fast start or fast stop, so the round now needs two switches to go at different times, once on the rocket acceleration, once on the decelleration due to hitting the target

"Mercury switch"? Did I miss something? What does electricity have to do with penetration?

 Lynata wrote:

easysauce wrote:bullets are normally fired at speeds in excess of the speed of sound,
if you fire a conventional bullet, at this speed, then add rocket propulsion, it wont speed it up at all

Well, at least in GW fluff, bolter rounds leave the barrel "at low velocity" before the rocket motor kicks in. And at least Stalker bolts are "sub-sonic".

easysauce wrote:even if it did, it would destabilize the projectile when the sudden accelaration kicked in

This may just be a case of sci-fi futuretech being fine-tuned sufficiently to prevent drastic changes. However, the 2E Wargear book does say that bolter accuracy really sucks at long range - it's a short range weapon, and the rocket motor isn't there to let the projectile fly further but just to crash into the target with added kinetic force. So in a way, you're spot on, but the gun is still working as intended.

easysauce wrote:not to mention mercury switches activate on change in momentum, ie fast start or fast stop, so the round now needs two switches to go at different times, once on the rocket acceleration, once on the decelleration due to hitting the target

"Mercury switch"? Did I miss something? What does electricity have to do with penetration?

Well... When a mummy and a daddy get together...

Oh, wait... You meant that kind of penetration... whoops, almost said to much!

Giving the term "bolter porn" a whole new meaning here.

 Lynata wrote:
Giving the term "bolter porn" a whole new meaning here.

Well, well, I see we have come to an understanding

easysauce wrote:
I still dont buy the rocket propelled theory that some fluff artists have put forth,

bullets are normally fired at speeds in excess of the speed of sound,

if you fire a conventional bullet, at this speed, then add rocket propulsion, it wont speed it up at all,

even if it did, it would destabilize the projectile when the sudden accelaration kicked in,

not to mention mercury switches activate on change in momentum, ie fast start or fast stop, so the round now needs two switches to go at different times, once on the rocket acceleration, once on the decelleration due to hitting the target.

none of the fluff has smoke trails coming off the rounds either, and I read far more fluf that treats the rounds as conventional.


as for extra ammo, even a 1" shell could easily be carried in quantity, esp for a large SM,

as an unmodified human, I can carry 200+ .77" rounds, and the only technology I need is a bandolier,

I do think it silly that most people dont attach the extra clips however, models shoot better with more ammo!

I think the idea behind it is that; as a conventional bullet will loose momentum and start to drop as soon as it leaves the barrel of a firearm, a rocket propelled bolt would not, but would be propelled by its own rocket - thus you'd get a consistent, flat trajectory, which would have longer range over a bullet, in theory. However, that doesn’t really give it an advantage over the bullet at close to medium ranges – the range the Astartes are generally fighting at.

As to the trail of smoke. Yes, it is in the fluff. The Sandy Mitchell books – Caiphas Cain – states that bolts leave a thin trail of smoke behind them. Also, in one of the newest BL novels; Baneblade, the author states that bolters have a unique double-bang report when fired. One bang for the propellant igniting, pushing the bolt out of the barrel, and the second bang is the bolt’s jet igniting.

To expand on what I posted earlier (re: accuracy/range), this is the description from the Wargear book:

"It is a short, compact weapon that fires a small missile or bolt considerably larger than an ordinary bullet. The bolt contains an armor piercing tip, an explosive, and a mass reactive detonator. It is shot from the barrel under low velocity, it's own propellant igniting once the missile is clear of the barrel.

The explosive detonates only when it has pierced armor. Any sudden increase in local mass activates the explosive and blows the target apart from the inside.

Boltguns are noisy and their effects are visibly devastating. Effective range is not great, and they are thus ideally suited to a shock/assault role."

And then there is the 3rd bang when the things detonate Iain Banks does a good description of bi-propellant ammunition in Against a Dark Background, that I recommend that all should read

 Lynata wrote:
To expand on what I posted earlier (re: accuracy/range), this is the description from the Wargear book:

"It is a short, compact weapon that fires a small missile or bolt considerably larger than an ordinary bullet. The bolt contains an armor piercing tip, an explosive, and a mass reactive detonator. It is shot from the barrel under low velocity, it's own propellant igniting once the missile is clear of the barrel.

The explosive detonates only when it has pierced armor. Any sudden increase in local mass activates the explosive and blows the target apart from the inside.

Boltguns are noisy and their effects are visibly devastating. Effective range is not great, and they are thus ideally suited to a shock/assault role."

yeah, sorry, IRL mass reactive shells usually use a mercury switch, or other momentum based "swtich"

while the projective travels forward at a high velocity, the mercury is pushed back, keeping the circuit open,

but as soon as the projectile slows down suddenly, the mercury goes forward and closes the switch, triggering the 2ndary explosion, but to prevent that from going off when the gun was fired, or when the rocket kicks in, means one momentum/mercury switch after conventional discharge to set the timer on the rocket, and release the 2nd momentume/mercury switch from lock down so the round doesnt blow prematurley when the conventional charge, or the rocket go off.

the 2nd "switch" would have to be there for true "mass reactive" rounds, otherwise its just eploding at a predetermined distance/time as opposed to knowing when its inside a target from slowing down.

OBS I am looking at fantasy future tech with my "real world engineer" goggles, so thats why I like to reconcile the bolter a bit more with pysics as we know it see how I would actually make one of these.

thanks for that quote BTW, knowing that the bolts exit the barrel off the conventional charge at a slow rate could make rocket propulsion do able assuming we can stabilize the round through fins/centripital force, and can over come the destabilisation that occurs when a projectile enters/leaves the sound barrier.

but it means the bolt starts off slow, then accelerates due to the rocket, meaning there is a lack of power close up, and point blank shots would be 100% on the conventional, and weak, charge till the rocket brought the projectile up to speed

so close range the projectile would be fairly weak untill the rocket brought it up to speed, despite it being a short ranged weapon,

at a certain range,
IE after the conventional charge, but before the rocket has ignited, or brought the bolt up to speed,
then bolts would just bounce off.

so if a space marine walked up to an ork, put the barrel against the orks head and shot him point blank

the bolt would barely do anything, but the same bolt from say 10m away would

again, not saying it works this way in fluff, just applying RL physics for laughs

The conventional charge that sends it down the barrel can still be plenty powerful enough to be deadly to most targets. "Low velocity" is a relative term, after all. If it's doing three times the speed of sound once the rocket kicks in, but only one-and-a-half times the speed of sound at the muzzle, that's plenty fast enough for an armor-piercing explosive shell to ruin your day.

easysauce wrote:yeah, sorry, IRL mass reactive shells usually use a mercury switch, or other momentum based "swtich"
while the projective travels forward at a high velocity, the mercury is pushed back, keeping the circuit open,
but as soon as the projectile slows down suddenly, the mercury goes forward and closes the switch, triggering the 2ndary explosion [...]

Ah! Now I understand.

The Stalker round is not meant to explode, the mercury only seems to be there for added mass. At least that is how I was interpreting the cross-section ... keeping in mind that this ammunition is used for covert ops where things are supposed to be kept quiet.

I've read of mercury switches, but never heard of them being used in ammunition, so thanks for that.
As far as reconciling sci-fi tech with the real things is concerned I feel as you do, although you're probably a bit more "disadvantaged" due to being more knowledgeable and thus more easily spotting things that would not work. Sometimes, ignorance is bliss, as the saying goes.

easysauce wrote:but it means the bolt starts off slow, then accelerates due to the rocket, meaning there is a lack of power close up, and point blank shots would be 100% on the conventional, and weak, charge till the rocket brought the projectile up to speed
so close range the projectile would be fairly weak untill the rocket brought it up to speed, despite it being a short ranged weapon

It probably depends a lot on how much "kick" the rocket motor is able to deliver, given that it seems to start the moment the round is leaving the barrel. Did you notice how there seems to be a "secondary" barrel to a bolt weapon, the one protruding from the front with the holes on the side? This is not the "primary" barrel, for a bolt round is much smaller than that...

Perhaps we could assume that the missile kicks in as the projectile passes this point; this would allow the bolt a few milliseconds to pick up speed whilst still keeping recoil low as the gases have sufficient free space to expand. It might still not be recommendable to shoot someone by pressing the secondary barrel against their body, but combined with the sharp diamantine tip it could be enough, even against an Ork. Unless we assume their skin is so tough that it'd be completely impervious to something like a Guardsman's bayonet.
One of the bolter's advantages is also that the rocket motor keeps burning even when the projectile is already in contact with an obstacle such as skin or armour. A normal bullet expends much (or all) of its kinetic energy in the process of penetrating the target, whereas a bolt round would "keep on pushing" until it either detonates or burns out. In essence, the bolt only needs to "get stuck" enough so that the continuous thrust would push it further into the target. It may not be much as the entire thing plays out in the blink of an eye, but I could imagine it makes a difference?

 Lynata wrote:

easysauce wrote:yeah, sorry, IRL mass reactive shells usually use a mercury switch, or other momentum based "swtich"
while the projective travels forward at a high velocity, the mercury is pushed back, keeping the circuit open,
but as soon as the projectile slows down suddenly, the mercury goes forward and closes the switch, triggering the 2ndary explosion [...]

Ah! Now I understand.

The Stalker round is not meant to explode, the mercury only seems to be there for added mass. At least that is how I was interpreting the cross-section ... keeping in mind that this ammunition is used for covert ops where things are supposed to be kept quiet.

I've read of mercury switches, but never heard of them being used in ammunition, so thanks for that.
As far as reconciling sci-fi tech with the real things is concerned I feel as you do, although you're probably a bit more "disadvantaged" due to being more knowledgeable and thus more easily spotting things that would not work. Sometimes, ignorance is bliss, as the saying goes.

easysauce wrote:but it means the bolt starts off slow, then accelerates due to the rocket, meaning there is a lack of power close up, and point blank shots would be 100% on the conventional, and weak, charge till the rocket brought the projectile up to speed
so close range the projectile would be fairly weak untill the rocket brought it up to speed, despite it being a short ranged weapon

It probably depends a lot on how much "kick" the rocket motor is able to deliver, given that it seems to start the moment the round is leaving the barrel. Did you notice how there seems to be a "secondary" barrel to a bolt weapon, the one protruding from the front with the holes on the side? This is not the "primary" barrel, for a bolt round is much smaller than that...

Perhaps we could assume that the missile kicks in as the projectile passes this point; this would allow the bolt a few milliseconds to pick up speed whilst still keeping recoil low as the gases have sufficient free space to expand. It might still not be recommendable to shoot someone by pressing the secondary barrel against their body, but combined with the sharp diamantine tip it could be enough, even against an Ork. Unless we assume their skin is so tough that it'd be completely impervious to something like a Guardsman's bayonet.
One of the bolter's advantages is also that the rocket motor keeps burning even when the projectile is already in contact with an obstacle such as skin or armour. A normal bullet expends much (or all) of its kinetic energy in the process of penetrating the target, whereas a bolt round would "keep on pushing" until it either detonates or burns out. In essence, the bolt only needs to "get stuck" enough so that the continuous thrust would push it further into the target. It may not be much as the entire thing plays out in the blink of an eye, but I could imagine it makes a difference?

What's the source of that Storm Bolter diagram?

The 3E rulebook. It also has similar descriptions for the lasgun, meltagun and autocannon, albeit sadly without cross-sections.

yeah, I like the idea of the large opening at the end being a chamber where the rocket actually ignites, i

that actually would make physical sense as well, since even a 1" caliber shell isnt THAT thick at that scale,

so the bolt would leave the barrel under its own power,

but as soon as it hit that large bit that looks like a compensator to redirect the gasses sideways (which makes sense for normal ballistics, AND for the rocket ballistics as the back thrust from the rocket would be dealt with nicely by it)

it ignites the rocket, in a small rocket tube almost, and off we go,

and yes, the whole thing about weak charge being relative could be important too,


it would make sense to have the initial charge still be as strong as possible, and at least super sonic to avoid the extra destabilizing effect of breaching the sound barrier out side the barrel,
not to mention making for a more powerful round more quickly out the barrel.

why dont they pay me to make real bolters... I now think that it is actually feasible to make one,

not probable... but possible

but Id need to be playing with a few million worth of CNC machinery, high explosives, ect...

probably not going to happen :(

Well, the destabilisation probably does not matter so much if the weapon is not even intended to be accurate on long range ...

But as far as your wish to tinker on real life bolters goes - perhaps you should pitch that idea to the Experimental Cartridge Company ltd. They're the ones who came up with the Frag-12 series of shotgun slugs, including the high explosive armour-piercing one. It's a stretch, but maybe they would fund a project like adding a tiny rocket motor to a 23mm slug. It could have its uses, such as disabling vehicles by punching through motor blocks etc.

Your chest might explode.

So are we done with this and ready to move on to something else?

 Lynata wrote:
Well, the destabilisation probably does not matter so much if the weapon is not even intended to be accurate on long range ...

But as far as your wish to tinker on real life bolters goes - perhaps you should pitch that idea to the Experimental Cartridge Company ltd. They're the ones who came up with the Frag-12 series of shotgun slugs, including the high explosive armour-piercing one. It's a stretch, but maybe they would fund a project like adding a tiny rocket motor to a 23mm slug. It could have its uses, such as disabling vehicles by punching through motor blocks etc.

this is the only rocket propelled pilstol/rifle type thing I have ever found http://en.wikipedia.org/wiki/Gyrojet

sounds like something out of 40k too!