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There's no indication in the fluff that a bolter shell takes a long time to get up to speed, so most likely the propellant fires quickly enough that acceleration time is not significant. Back in 1st edition when weapons had range modifiers, bolters actually got a +1 to hit at short range like most basic weapons, and bolt pistols got a +2 to hit at short range like most pistol weapons, so there's no rule support for bolters being weak at short range even back when rules would have accounted for that.

Melissia wrote:I think you're WAY overestimating the size of bolter shells. .75 cal is 3/4ths of an inch in diameter-- about 19.05 milimeters thick. Keep in mind that Space Marines are well over eight feet tall when in power armor, and then look at the clips again. Their size is deceptive.

In all of the pictures a bolter shell is shown to be shaped like a pistol cartridge, with a 'bullet' (maybe 'warhead' is more appropriate) and a casing with propellant that is about the same diameter as the bullet/warhead, not heavily tapered like a rifle shell. A shotgun shell also holds to a cylinder shape, although even slugs usually have a paper or plastic casing around the projectile. A 12-gauge shotgun is about .73 caliber, so a bolter barrel is about the size of a regular shotgun, and its ammunition is about the size of a shotgun shell. Bolters as described are not as big and unweildy as some people think they are, they're a surprisingly reasonable weapon for something thought up by a bunch of guys who likely know zip about firearms.

Here's a pic I found of a short-barreled shotgun with a 10-round magazine, it's something a normal human can manipulate pretty easily. Scale up the magazine and gun body to fit in with a 8-foot armored giant, and you can easily make it a 2-column magazine and 1.5x as long to contain 30 rounds. This is the first pic I've tried uploading, so hopefully it works.

Actually it's mostly Astartes bolters which are big and unwieldy. Without their superhuman strength, they'd not be able to fire them accurately.

Human bolters are much better designed.

gendoikari87 wrote:In general it's used for free fall, not specifically but it's what MOST people refer to when they say free fall. But if your already going faster than the "terminal" velocity your velocity is not constant, so yes you were apparantly taught wrong, because then you slow down to that terminal velocity.

In general the concept may be introduced when discussing falling objects but in this case we are using it to work out the top speed of projectiles. Wether or not you are travelling faster or slower than your terminal velocity is irrellevant as you will still either speed up or slow down until the forces balance anyway, at which point the terminal velocity is reached. The concept that i was taught wrong is laughable, although if you had said that i had misunderstood i would be far less offended and would have reconsidered my position. Leading universities always teach you rubbish eh? Although in the case of classical physics it is all wrong anyway, if we were to use the most accurate physics then it is all wrong by billionths of a percent due to relativity anyway.

I did not mean to offend mearly point out an inaccuracy for a specific case (because I misread what you said), I meant it mostly as comical.

Although in the case of classical physics it is all wrong anyway, if we were to use the most accurate physics then it is all wrong by billionths of a percent due to relativity anyway.

Ironically I'm sitting here working on General relativity. The particular case of proper time verses earth frame time for a satelite.

Don't sweat it, offended was probably too strong a word anyway. Been about three years since i did this stuff academically. Time really can be annoying in those tasks, all four dimensional vectors and Lorentz transformations. General relativity is even more bizarre. I think that the idea "If you are not confused when you first hear it, then you haven't understood it" is sound advice.

I remember bill phillips telling us that when he came to give a guest lecture to our quantum class a few weeks ago( as well as a lecture to our General relativity class). I was lucky enough to be taking both classes, and see both lectures. In any case I should count myself lucky that our GR class uses the wheeler arcibald book that reduces the math of General down to derivatives, integrals and simple algebra.

Bill Phillips the Nobel prize winner? That sounds interesting. Did a bit of laser cooling work at uni, really fun concept. Imagine a Bose-Einstein condensate gun for your troops, wonder what its stats would be...

Anyway, on topic and as lasers came up anyway, i always wondered how the smeg lasguns had recoil. I don't know if i just imagined this but they should not, correct? Other than the miniscule amount because of photon mass that is.

I don't know if i just imagined this but they should not, correct?

well the photon DOES have some momentum, and so it DOES have recoil... problem is to produce the force of a gram, the beam needs to be like 100000 mega watts. I've done the calculations before but if you actually do the math you get more bang for the buck out of kinetic energy penetrators, just simply due to the high specific heat of carbon and water. Now for a sniper rifle... I might go for that laser but as a general rule projectiles trump lasers for energy transfer into damage to the opponent, lasers tend to cauterize, and don't have the hydrostatic shock of bullets. but then again theres no supply train for a rechargable battery pack.

Bill Phillips the Nobel prize winner? That sounds interesting. Did a bit of laser cooling work at uni, really fun concept.

You have actually done some laser cooling? That's amazing, what's your setup like? He explained the basics to us and I was like, wow that is really really simple and brilliant, in a word, elegant. Then he started telling us about his funnel design and i was like... okay, I now know why this guy got the nobel prize. At the moment all I'm doing is working on the laws of internal ballistics, mostly the second law of thermodynamic with a non uniform powder burn rate, and the double integral of time and volume is kinda befuddling me.

Ack, that did sound like i did some experimental laser cooling didn't it? I'm not that cool (pun intended), just meant that i had covered the theoretical side of it. I always found that theory was more interesting anyway, wish i had of done a masters in theoretical physics instead of just normal physics with lab work. Something always ended up throwing my experiments off a bit, like someone walking into my table while i took lunch and blowing a mornings work out the window.

I just can't get the idea of six lasguns firing at a carnifex out of my head. I know it wouldn't work on such large amounts of matter, but i wonder what would happen to super cold carnifex molecules...

I just can't get the idea of six lasguns firing at a carnifex out of my head. I know it wouldn't work on such large amounts of matter, but i wonder what would happen to super cold carnifex molecules...

It wouldn't work, in 40k all lasers heat stuff up no matter of respective initial velocity vectors. Aparantly the absorption spectrum in 40k is continuous and not discrete.

Must be the warp. Or tyranids ate it. Or a wizard did it...

Wizard, of course it was Tim. as he alone can prevent the ultraviolet catastrophe in a world of continuous spectrum.


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as a side note I found a pic of something I made years and years ago in high school it was basically a high initial impulse bolter shell that used a small rocket to overcome air resistance and provide additional spin. Looking at it now, it's a horribly flawed design, but I was very young then.

Yeah, I wouldn't worry about it too much. Most 40k stuff doesn't work beyond IT'S MAGIC! anyway. The calibers are ridiculous, designs poor, armor filled with flaws/bullet traps/etc. vehicles lack basic suspenision (or in rhinos any realistic place for an engine), etc. And it would all be kinda of pointless because with guiant spaceships with all their gee-whizzery, they could annihilate whole armies from space anyway.

It's just a neat excuse to push around guys in armor firing big guns at aliens and monsters in space. PEW PEW!

Tau railguns are already have prototypes. Basically it fires fridge sized solid rounds many times the speed of sound.

Bolters are scream-powered.

Nay, Noise Marine weaponry is scream powered ;-)

I'd say this.
Bolt weaponry can't be really described as a true Gyrojet weapon since we have sources which give them recoil and those that don't give.
After looking at the sources and comparing them with each other I'd say that Bolter are really some bastard weapons.
Know that loud thing,in Inquisition Wars Draco's Bolter is said to be created to be loud.


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Mr Nobody wrote:Tau railguns are already have prototypes. Basically it fires fridge sized solid rounds many times the speed of sound.

Imperium also has Railguns on ships.

As for the Lasguns we have 19 Megathule(I assume that Megathule is corruption of Megajoule) source and most of other sources give them level of firepower near that.


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Plasma pistol fully cremates a Human in one novels.That gives them 400 megajoules(the amount of energy required for cremating human body).
Lascannons range from triple digit megajoules to single digit gigajoules.
In Caves of Ice a meltagun "instantly flashes" a dozen cubic metres of ice which gives it some 32 gigajoules.

gendoikari87 wrote:
Autocannons- just that 20-30mm autocannons (though the OLD OLD OLD OLD wargear book says they are basically modern tank cannons, most of the new stuff puts them at around the level of a high end bushmaster)

Most of this thread was about bolters, but I wanted to take exception with this.

Don't presume we have any kind of technology today that mimics 40k technology just because it uses the same name.

40k autocannons use materials and physics not obtainable in the real world, just like most of everything else in 40k.

That 20-30mm autocannon would be more akin to a heavy bolter in terms of power, since they'd be unlikely to damage a Rhino, and unable to damage anything tougher.

@gendoikari87: Actual science has no place in these discussions as any attempts to reproduce most of the stated effects per the warhammer fluff using scientific means is impossible.

Take the bolter arguement for example. In Mellissia's quotes it is assumed that the bolter craps out shots that are already at terminal velocity as soon as they leave the barrel - thus no difference in damage at long range or short. I know nothing about gyrojets as a technology - but from what I do know about balistics - the shell diagram you showed doesn't suggest that the stated mode of operation is achievable using 21st century conventional means - and needs some sort of 41st millenium voodoo to function.

The funny thing about going to the fluff for support is that the fluff itself is contradictory. Those who lean entirely on the fluff for their support are keen to dismiss any fluff damaging to their cause...

Take Ivan's lasgun numbers. Fluff adherents will keep posting the quotes which show damage output and ignore the fact that:

1. Megajoule output numbers are moving towards the range of modern tank-level weapons.
2. Lasguns are noted in fluff to be able to be recharged in a fire.
3. Reputed to be a plasma weapon, they need ammunition, one might infer that since the fire recharge is stated to work (and presumably doesn't replenish whatever the plasma is), that they are in fact some sort of high tech voodoo weapon.

At the same time they'll challenge you to "prove" that the numbers should be lower... It is this "moving the goalposts" mentaility that makes any sort of rationalization of the 40k fluff impossible.

@keezus
Do you think that Lasguns are some kind of low-powered plasma weapons,I mean they have recoil?
I've always wished that GW finnaly makes some coherent cannon policy like in SW so that we can put end to these debates.

Are you guys REALLY complaining about the lack of a source that has information of a fictional weapon?

LordTyphus wrote:Are you guys REALLY complaining about the lack of a source that has information of a fictional weapon?

Yeah we do on many forums.
Go to the SpaceBattles.com or to StarDestroyer.net.
They'll give you all the info.

Bolt weaponry can't be really described as a true Gyrojet weapon since we have sources which give them recoil and those that don't give.
After looking at the sources and comparing them with each other I'd say that Bolter are really some bastard weapons.
Know that loud thing,in Inquisition Wars Draco's Bolter is said to be created to be loud.

well all we really know is that they have a lethal level of velocity at muzzel, so it's more than likely a hybrid system but that still means they are more dangerous at long range than at short, still making my point valid. But the main problem is accuraccy, If I didn't know any better i'd say bolts are guided. but I have no source stating this...

Most of this thread was about bolters, but I wanted to take exception with this.

Don't presume we have any kind of technology today that mimics 40k technology just because it uses the same name.

40k autocannons use materials and physics not obtainable in the real world, just like most of everything else in 40k.

That 20-30mm autocannon would be more akin to a heavy bolter in terms of power, since they'd be unlikely to damage a Rhino, and unable to damage anything tougher.

Actually that's not true, the IG codex specifically draws comparisons to modern day autocannons of the same calibers. A lot of other sources including lexicannum give the same comparison. Only diffence is the imperium seems particularily fond of "high explosive shells"
EDIT: I thought the IG codex did I remember A codex comparing them to modern autocannons, at any rate they look just like a bushmaster. They're used in the same way and even used for anti-aircraft. Though the OLD sources state they're more like tank guns..... which isn't much different if you look at WWII tank guns and Modern autocannon rounds. 72-87mm versus 30mm High velocity. Course if they mean 120mm Rhinemattal shells they shells themeslves would behalf the size of a guardsman in length, but they're barely more than a hand over fist... which is the 30mm.

In Caves of Ice a meltagun "instantly flashes" a dozen cubic metres of ice which gives it some 32 gigajoules.

I have suspicions based on some descriptions that a melta gun is really just a positron beam weapon.


also has any body been able to find an in depth description of krak missiles for me? All I can find is hollow charge. Which leans to them being Gen II but Gen III is a LOT stronger i can't see why they don't use them... it's a copper liner for emperors sake....

gendoikari87 wrote: at any rate they look just like a bushmaster.

Looks like? That's hardly any kind of reasoning to hold in a logical debate where one weapon exists in our world and another exists in a world where it's made of unobtainium, firing nonsensoleum charged bullets, and operated by magic-voodoo spirits.

DarknessEternal wrote:

gendoikari87 wrote: at any rate they look just like a bushmaster.

Looks like? That's hardly any kind of reasoning to hold in a logical debate where one weapon exists in our world and another exists in a world where it's made of unobtainium, firing nonsensoleum charged bullets, and operated by magic-voodoo spirits.

True but even for 28mm heroic those shells are way too small to be tank shells. but they do fit into the 20-30mm range. Maybe 60mm WWII shells but that's a streach and a big one.

IvanTih wrote:I'd say this.
Bolt weaponry can't be really described as a true Gyrojet weapon since we have sources which give them recoil and those that don't give.
After looking at the sources and comparing them with each other I'd say that Bolter are really some bastard weapons.
Know that loud thing,in Inquisition Wars Draco's Bolter is said to be created to be loud.


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Mr Nobody wrote:Tau railguns are already have prototypes. Basically it fires fridge sized solid rounds many times the speed of sound.

Imperium also has Railguns on ships.

As for the Lasguns we have 19 Megathule(I assume that Megathule is corruption of Megajoule) source and most of other sources give them level of firepower near that.


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Plasma pistol fully cremates a Human in one novels.That gives them 400 megajoules(the amount of energy required for cremating human body).
Lascannons range from triple digit megajoules to single digit gigajoules.
In Caves of Ice a meltagun "instantly flashes" a dozen cubic metres of ice which gives it some 32 gigajoules.

Yeah. I've read alot about that.
The Imperium does have Railguns. You just never hear about them as they are so simple. Anyone can speed a projectile to the speed of sound.

It doesn't take a whole lot to make a rail gun couple copper rods some wires and a nail..... now to make an effective one... a little bit more... to make one on the level the tau make them... a LOT more.

IvanTih wrote:@keezus
Do you think that Lasguns are some kind of low-powered plasma weapons,I mean they have recoil?

My pedestrian understanding of plasma based weaponry is that superheated material is placed in some sort of charged bubble and propelled along a magnetic coil towards the target at high velocity. Damage is done through heat transfer, with efficiency decreasing as heat is lost into the environment during travel. In the case of a lasgun, assuming it uses the same principle - the mass of the projectile is most likely negligible - as it would be firing a pellet of plasma (as opposed to an actual plasmagun which fires a more damaging blob of plasma). As such, I don't expect there would be much recoil. In the 40k vs. everything thread, I got beat down with a pile of posts indicating that las-weapons are low powered plasma weapons after assuming they were laser weapons... as recharging a plasma gun in a fire, low powered or not didn't seem to make much sense.

No matter which way one tries to rationalize the stated effect in the cited fluff - there is almost ALWAYS other fluff that contradicts it. IMHO, that's why trying to explain 40k effects using scientific rationalization is a fool's errand.

there is almost ALWAYS other fluff that contradicts it. IMHO, that's why trying to explain 40k effects using scientific rationalization is a fool's errand.

yeah but it's still fun to physicists and engineers.

as for lasguns, I've heard a million excuses for the recoil raging from being plasma to actually having a mechanism in it that emulates recoil as to not freak out the user who is used to firearms. Personally, though the fluff contradicts it, I like to think they are pure laser weapons. A laser will produce recoil, but to produce a gram (or rather the equivalent FORCE of recoil under earth gravity) of recoil you need something like 10,000 Kilowats. so any real recoil would mean that a lasgun is the end all be all of matter vaporizers!!!!

The only source I have ever seen that outlines a bolter shell as being potentially weaker at short range is in the Ultramarines novels.

At one point, the main character fires his bolt pistol at a Dark Eldar archon at extremely short range. Due to the distance (2-3 feet), the round does not have time to arm the explosive charge, and thus doesn't explode (it instead tears through his throat and passes through the back).

This would make it weaker against infantry (no explosion=less collateral damage), but better against armoured tagets (the round essentially becomes a high-powered slug)

This is the only example I have ever seen of a bolter being potentially weaker due to distance, and even then it still become more potent in a different aspect.

S_P