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 Grey Templar wrote:

FezzikDaBullgryn wrote:
if we are complaining about the physics of bolt guns, Storm Bolters are depicted endlessly putting out a "Storm of Bolt rounds" A veritable wall of lead. The size of the rounds in question, and they being MAgazine fed, means they couldn't hold more than 50 rounds at a magazine. That means 20-30 rounds per barrel. Not really a "wall of lead" considering the standard Assault Cannon has 6 barrels and is reported to put out 2000-3000 rounds per minute. Or 30-60 per second.

In fairness, that is how all guns in media of any kind tend to get depicted. Bottomless mags are a staple of games and movies.

And most guns are capable of emptying their magazines extremely quickly if fire is sustained. The Assault Cannon is basically an M134 minigun, which has a fire rate of between 2 and 6k RPM. But the most ammo any variant has is 5k rounds in a belt, and some only have 500. So even real guns often only have a minute of ammo at a time anyway.

Realistically, storm bolters will be used in quick accurate bursts. Expending 2-6 rounds per burst taking out specific targets.

Fun Fact, due to the insane rate of fire on a 20mm Vulcan Gatling cannon (see any aircraft gun made in the 21st century) the pilot has between 4-6 seconds of actual ammo. And so do short, quick bursts, instead of what they did in the 1950s and walk their tracers onto the target.

The funny part about what I was saying with the storm Bolter is that certain writers always make a concerted effort to "appear" like they have very little ammo. Ciaphas Cain is always running dry on his pintle mount, or the terminators are always almost empty. Given the size of the mags, even terminators would have a hard time effectively "storing" extra mags.

It's a ludicrously stupid weapon both immaginatively and narratively. Whoever dreamed it up was smoking something funny.

My handwaivium in that is that TDA is more than large enough to accommodate extra mags. Canonically PA/TDA has magnetic clamps which can hold grenades and extra weapons, and presumably magazines too.

If and when I get around to making another vanilla marine army, I would definitely make the effort to put spare mags on everybody.


As for the constant running out with certain writers, I think that is a cheap way for tension to get built. Not a bad way, just a cheap way. It drives home how this specific situation has become a problem.

99% of the time marines are going to be victorious quickly and walk all over their enemies. They may not even need to reload sometimes. But good stories aren't the ones where the bad guys fold like a cheap suit.

Re: Storm Bolters - If we're goimg by the proportions given by the models and images, those clips are thick enough to house several rows of bolt ammunition. How does the mechanism work? I dunno! But it sure looks like there's a lot of room in there.

Re: Assault Cannon - It could be that the AC has variable RPM, like from a few hundred rounds per minuite up to a few thousand, and therefore be optionally more conservative with ammunition if deployed for more sustained and suppressive effect.

But I also agree that Terminators should be visibly well loaded up with spare ammunition, and it's nice that many of the Storm Bolters these days are modeled as drum-fed.

I remember from the Space Hulk game that canonically Terminators do carry spare ammunition and can reload during combat. The assault cannon can burn through ammo pretty quick though.

And if we assume that bolters are only .75 caliber and going by the size of marines and storm bolters on more recent models then those drums could actually hold a lot of ammo.

.75 is a large caliber, but marines and stormbolters are big too. A stormbolter would seem to be at least on par with an M249 in overall bulk. The real question is what the length of the cartridge is.

I doubt that .75cal bolt ammo is as long as .50BMG(12.7x99), nor as short as say 7.62x54r or 7.62x51mm. You could maybe justify bolters being .75x60mm perhaps?


Even with a cartridge that huge, if you had a drum magazine the size of an M249 belt box you could have 60-80-100 rounds in a magazine which kinda lines up with what GW gives for magazine sizes. And even 24-30 round mags would be manageable for normal bolters. Definitely very wide front to back, but in terms of length not too much larger than IRL magazines given they are double stacked.

The larger size might even be a good thing, perfect for the large hands of terminator gauntlets so they're not fiddling with something small and delicate.


I would love for someone to make a wildcat cartridge specifically so we could make some bolter analogs today. Maybe not rocket ammunition quite yet, just a .75x50-60mm monster.

Neopup is 20x42mm (apparently). Frag12 is apparently around 20x50mm. The Frag12 Wikipedia page has a list of other similarly sized rounds.

https://en.m.wikipedia.org/wiki/FRAG-12

One of the reasons they are not in wider use is that international law is against use of exploding bullets against individual people. Also normal bullets are good enough for most squishy targets on earth.

 Flinty wrote:
Neopup is 20x42mm (apparently). Frag12 is apparently around 20x50mm. The Frag12 Wikipedia page has a list of other similarly sized rounds.

https://en.m.wikipedia.org/wiki/FRAG-12

One of the reasons they are not in wider use is that international law is against use of exploding bullets against individual people. Also normal bullets are good enough for most squishy targets on earth.

Well, the Orks haven't found earth yet. . .

The size of the ejection port suggests a long cartridge. But it also suggests the cartridge is almost as wide as the magazine.

I imagine that the rocket is sat inside the cartridge further back than normal bullets, so it acts as a sleeve, giving a rocket and a cartridge Almost the same length.

The ejection port on a gun always needs to be way larger than the casing, so I wouldn't necessarily take it as an indicator of the size of the casing.

FezzikDaBullgryn wrote:
Fun Fact, due to the insane rate of fire on a 20mm Vulcan Gatling cannon (see any aircraft gun made in the 21st century) the pilot has between 4-6 seconds of actual ammo. And so do short, quick bursts, instead of what they did in the 1950s and walk their tracers onto the target.

They also don't eject the brass, but rather place it in a storage compartment. These are often engraved as souvenirs.

Because I was never a popular guy, I served in two wings and never got a bloody casing. :(

The funny part about what I was saying with the storm Bolter is that certain writers always make a concerted effort to "appear" like they have very little ammo. Ciaphas Cain is always running dry on his pintle mount, or the terminators are always almost empty. Given the size of the mags, even terminators would have a hard time effectively "storing" extra mags.

I don't think they thought that far ahead or knew that much about it.

When George Lucas set out to make Star Wars, he recruited concept artists who had experience in practical design of aircraft and vehicles. This made the setting look much more realistic than much of went on before.

I don't think GW had the option of hiring artists with extensive firearms design experience, but rather got guys who knew artistic convention and specialized in look and feel.

That's why the guns are chunky, awkward, and don't really work. Seriously, why wouldn't storm bolters be fed from a rear harness protected by armor plate? Why have an exposed detachable box magazine at all? The chassis could probably hold hundreds of rounds. The answer was that no one thought that far ahead. It's just a guy in a big armored suit holding a big gun.

That's one of the only things I like about the aggressor design, the belt feed.

Commissar von Toussaint wrote:


That's why the guns are chunky, awkward, and don't really work. Seriously, why wouldn't storm bolters be fed from a rear harness protected by armor plate? Why have an exposed detachable box magazine at all? The chassis could probably hold hundreds of rounds. The answer was that no one thought that far ahead. It's just a guy in a big armored suit holding a big gun.

Well, a belt fed from a harness would be a potential liability. They are more likely to jam and are more difficult to clear, especially for a dude in massive armor.

Box magazines are used because they are the most reliable feeding mechanism.

 Grey Templar wrote:

Commissar von Toussaint wrote:


That's why the guns are chunky, awkward, and don't really work. Seriously, why wouldn't storm bolters be fed from a rear harness protected by armor plate? Why have an exposed detachable box magazine at all? The chassis could probably hold hundreds of rounds. The answer was that no one thought that far ahead. It's just a guy in a big armored suit holding a big gun.

Well, a belt fed from a harness would be a potential liability. They are more likely to jam and are more difficult to clear, especially for a dude in massive armor.

Box magazines are used because they are the most reliable feeding mechanism.

^Nice, I was wondering about the reliability part.

 Grey Templar wrote:
Well, a belt fed from a harness would be a potential liability.

Why?

They are more likely to jam and are more difficult to clear, especially for a dude in massive armor.

Based on what? The assault cannon feeds vast amounts of ammo at a much higher velocity. Scaling it down to storm bolters would have a fraction of the difficulty.

Again, how do you change mags with a power/chain fist/lighting claw? Do you expose the left hand? Where are the extra mags stored? How many are carried?

A powered harness feed makes much more sense, but GW's artists didn't think that far ahead.

A belt inside a protective metal sheath leading to a backpack ammo supply, much like the M163 Vulcan and other related "miniguns", have a lot of surface area for the belt of ammunition to snag on compared to a box magazine. They're not horribly unreliable or they wouldn't be used, but if a jam does occur you need to disassemble the whole thing. That would be basically impossible when you are wearing the weapon system integrated into your armor.

And reloading a weapon using a feed system like this takes a long time. 30-40 minutes.

Compare this to a box magazine where you just need to drop the mag, rack the slide a few times to clear, then put the mag back in. Its not so much about being more reliable in a vacuum, but more about how you can clear it in the field. A feed system to a backpack would be basically unfixable if it broke or jammed while you were in combat. This would also make resupply easier. If a terminator needs more bolter ammo, just drop him more loaded magazines. If he had a backpack feed system you would need to drop the ammo and then have someone manually feed it into the system. Box mags hold less but are more convenient.

Powerfists don't completely ruin fine moterskills. The powerfield can be turned off and even with your oversized hands you can drop the empty mag, grab a new one, and slam it home. If they couldn't do semi-delicate things like reloading a box magazine(which remember is massive on a stormbolter) then why even have fingers? As proof of fine Moter skills, Marneus Calgar in the Ultramarines omnibus in one scene is drinking wine out of a crystal glass while wearing his power fists. Yeah, they are relics and super swanky, but if he can use a crystal flute then a normal terminator can reload his stormbolter.

Extra mags can be stored on the magnetic clamps that all power armor and TDA has around the waist and on the shins of the armor, they use those for extra weapons and grenades so why not extra mags. How many? going by the size, you could probably get at least 4 around the waist. More if you really tried.

Also, Terminator assault cannons usually have box magazines too, not belt feeds. Presumably for the same reasons as Storm Bolters.

Space Hulk suggests a Terminator carries one spare assault cannon magazine, and can get ~10 bursts from a single magazine. That is probably a simplification, but seems broadly reasonable.

The core problem with external ammo supplies is that Terminators are designed to get hit with all sorts of nastiness, which would destroy all that gear.

You can say that it's all very, very robust, but it can't be stronger than the armor itself.

And I'm sorry, box-magazines being more reliable than powered feeds? I'd love to see some data on that, since magazines are the number one cause of weapon stoppages.

To put it another way, imagine a tank where you store the ammo externally along the hull front and side. Incoming rounds don't have to defeat the armor, just the ammo boxes.

It's fine, its all magic science, but if you have belt-pouches of ammo, a frag missile will pretty much shred that harness and this is precisely what terminators are designed to withstand. No one thinks about it in a modern context because whatever will wreck your mags will wreck you as well.

The idea behind an interior feed is that it's within the suit's shell, and one could have cartridge-style reloads without need 30 minutes to rearm. There's no reason it has to function exactly like an aircraft weapon.

Sure but redesigning a holy DAOT suit to fit an internal feed is Heresy.

I feel people are forgetting we are talking about the Imperium of "lets use tank designs out of WW1" Man.

 Tyran wrote:
Sure but redesigning a holy DAOT suit to fit an internal feed is Heresy.

I feel people are forgetting we are talking about the Imperium of "lets use tank designs out of WW1" Man.

Well, the designs have changed a bit over the years as GW got better at sculpting, moving to plastic, etc.

I mean, the old dreadnought with the, er, crotch-rocket was something else. (Or was it a robot, I forget?)

I think the issue with the chain feed is that, unlike magazines, if the chain feed takes a damaging hit then that gun is going to stop firing and there's nothing you can do about it. Carrying magazines means that if one is hit and damaged, you can just swap to another one. It's got built in redundancy.

I also would imagine that Terminators would be storing them on their sides/back, whereas that chain mechanism has to be right there on the front of the arm with the weapon.

And if you have a chain feed attatched to your arm, can you ever put your weapon down?

Could do what I theorise Scions do with Hellgun cables and have both the long feed to use and magasines that can be slot in case the feed gets otherwise damaged.

Commissar von Toussaint wrote:
The core problem with external ammo supplies is that Terminators are designed to get hit with all sorts of nastiness, which would destroy all that gear.

A feed belt leading to the backpack would be far far more vulnerable than a box magazine. If a box mag gets damaged, its only 1 magazine. If your feed belt gets damaged while you are deep inside a hulk you are so. incredibly. boned.

You can say that it's all very, very robust, but it can't be stronger than the armor itself.

Correct, but again if a magazine gets damaged its only 1 magazine.

And I'm sorry, box-magazines being more reliable than powered feeds? I'd love to see some data on that, since magazines are the number one cause of weapon stoppages.

Yes, magazines are the main cause of jams. But magazines are very easy to clear and fix the jam. A fixed belt feed like a modern day Minigun uses if and when it jams is a problem that will take 30+ minutes to fix. A jam from a magazine fed weapon can be cleared in seconds.

This equals more reliability.

To put it another way, imagine a tank where you store the ammo externally along the hull front and side. Incoming rounds don't have to defeat the armor, just the ammo boxes.

It's fine, its all magic science, but if you have belt-pouches of ammo, a frag missile will pretty much shred that harness and this is precisely what terminators are designed to withstand. No one thinks about it in a modern context because whatever will wreck your mags will wreck you as well.

Yes, you risk damage to your gear when you get hit with stuff. The fact your exterior gear might be weaker than your armor just says your armor is really good.

This is what we call a First World Problem.

The idea behind an interior feed is that it's within the suit's shell, and one could have cartridge-style reloads without need 30 minutes to rearm.

TDA is big, but its not big enough to accommodate an interior belt feed along the arm to the weapon.

This would make the arm bulkier and less modular, since swapping weapons would mean replacing the entire arm and feed system of the armor to the new weapon. The Storm Bolter would also be integrated to the armor itself and be unable to be dropped. This could be a problem if the storm bolter got damaged. And again you have the issue that if a jam does occur it is impossible to fix in combat.

And yes, it is going to take a long time to reload such a system. Just look up how CWIS get reloaded. This is pretty much the only way you could have a backpack belt system.

It also means that the Storm Bolter can only be used by someone wearing the TDA as they are inseparable.

There's no reason it has to function exactly like an aircraft weapon.

You are exactly describing a vehicle mounted weapon feed system, aircraft or ground doesn't really matter. And jams are a big issue for vehicle weapons since they can't be cleared in the field, at least easily. Not as much of a problem with aircraft since you are going to head back to base anyway, but its less than ideal for someone who expects to be stuck in combat for extended periods.

There is no reason you couldn't have power armor that uses these internal feeds, but they have downsides. Downsides that would be a real problem for Terminators. The real point of power armor/TDA is to have the maneuverability and flexibility of infantry with the armor protection of a vehicle. Making their weapons the same as vehicle mounted weapons would somewhat defeat the purpose.

 Bobthehero wrote:
Could do what I theorise Scions do with Hellgun cables and have both the long feed to use and magasines that can be slot in case the feed gets otherwise damaged.

Yes, there could be a cutoff for box magazines and then one would have the best of both worlds.

You could do that. Though it is certainly easier with an energy weapon than a solid projectile.

But again unlike the lasgun version such a conversion on a solid projectile weapon would still be something that would take a bit of disassembly and modification to accomplish the switch.

So this is the exact reason the FN Minimi, or M249 LMG uses BOTH a belt feed mechanism, and a STANAG Magazine Feed system. If one fails, the operator can literally just jam their backup ammo (From their M4) into the feed slot, rack the slide, and go back to rock and rolling.

The Assault cannon does not have that option. Because obvious reasons. Also, the Storm Bolter is magazine Fed. This is all silliness on my part, and I apologize for taking us off tangent.