Forum adverts like this one are shown to any user who is not logged in. Join us by filling out a tiny 3 field form and you will get your own, free, dakka user account which gives a good range of benefits to you: No adverts like this in the forums anymore. Times and dates in your local timezone. Full tracking of what you have read so you can skip to your first unread post, easily see what has changed since you last logged in, and easily see what is new at a glance. Email notifications for threads you want to watch closely. Being a part of the oldest wargaming community on the net. If you are already a member then feel free to login now.

In the fluff bolters are described as being a sci-fi version of the gyrojet rifles that use a primer inside the shell as opposed to a primer that is kept inside a shell casing.
So if the rounds from a bolter do not use shells, then why is there an ejector slide on the side of the boltgun itself?

Don't know lore-wise, but my theory is that in the event of a jam or a round failing to fire it can be removed from the chamber allowing the next round to go in unhindered (and thus resolving the jam.)

Fluff seems to vary on whether or not bolters have shell cases to eject. Sometimes they do, sometimes they don't.

Nothing about Bolters really makes sense. They very clearly have been shown ejecting casings and ammunition using casings despite the fact that they've been described as caseless in some places. The fundamental concept of a rocket gun has also largely been proven to be somewhat ineffective, they've been made but since they don't reach maximum speed for some time after they leave the muzzle they can't hit the broad side of a barn (and if they had a booster charge to alleviate this there's no real reason to put a rocket engine in them). Other bolters have the magazines so far forward that a chambered round would basically be sitting right at the muzzle, or how most Bolter magazines would hold a tiny number of rounds...like 10

 Peregrine wrote:
Fluff seems to vary on whether or not bolters have shell cases to eject. Sometimes they do, sometimes they don't.

On one of the CSM mini-dex's it shows a CSM ejecting a shell from his daemonic looking bolter.
Thought id add that wrench into the gears.

The fluff varies on whether or not bolters actually have shell casings to eject. Like much of 40k, it require suspension of disbelief, since a bolter probably wouldn't actually work all that well in real life.

Just like laser weaponry in 40k doesn't work at all how a real laser behave, but since its Sci-Fi we go with the flow...

Whether or not the shell has a casing, you still need to be able to eject dud rounds, or be able to clear the breach for cleaning or stowing the weapon.

Yeah I really can't imagine how a rocket gun would be particularly effective in real life, especially for a fighting force that is supposed to be all about precision and efficiency like the space marines are.

 creeping-deth87 wrote:
Yeah I really can't imagine how a rocket gun would be particularly effective in real life, especially for a fighting force that is supposed to be all about precision and efficiency like the space marines are.

I think you've misunderstood what Space Marines are about.

They're not about precision and efficiency... They're about shock and awe.

The way Bolters function is that the bolter round contains both a powder charge and a rocket. When the Boltgun is fired the powder charge is ignited and the casing is expended. The resulting explosion propels the bolt head out of the gun at a high muzzle velocity. Then after a short amount of time the rocket engines on the bolt head kick in which accelerates the thing to even greater speeds.

It's kind of a hybrid between a regular firearm, a gyrojet and a grenade launcher.

 insaniak wrote:

 creeping-deth87 wrote:
Yeah I really can't imagine how a rocket gun would be particularly effective in real life, especially for a fighting force that is supposed to be all about precision and efficiency like the space marines are.

I think you've misunderstood what Space Marines are about.

They're not about precision and efficiency... They're about shock and awe.

Oh yeah, certainly, but you have to assume that a fighting force as small as a space marine chapter has to rank precision and efficiency pretty high or they wouldn't be able to get anything done with the small amount of numbers that they have. I mean hell, an entire chapter is only a thousand marines, and entire chapters never fight all at once. I donno, I confess I would have a hard time pointing to a specific example of 40K lore to back up my point, it's more a rationalization in my head for how marines should work.

 insaniak wrote:

 creeping-deth87 wrote:
Yeah I really can't imagine how a rocket gun would be particularly effective in real life, especially for a fighting force that is supposed to be all about precision and efficiency like the space marines are.

I think you've misunderstood what Space Marines are about.

They're not about precision and efficiency... They're about shock and awe.

Shock! And/or what exactly?

Simply the rocket uses solid fuel which is encased for protection, the rocket then leaves the casing when fired making it look an normal round.

 chromedog wrote:

 insaniak wrote:

 creeping-deth87 wrote:
Yeah I really can't imagine how a rocket gun would be particularly effective in real life, especially for a fighting force that is supposed to be all about precision and efficiency like the space marines are.

I think you've misunderstood what Space Marines are about.

They're not about precision and efficiency... They're about shock and awe.

Shock! And/or what exactly?

Shoulder Pads.

 TheCustomLime wrote:
The way Bolters function is that the bolter round contains both a powder charge and a rocket. When the Boltgun is fired the powder charge is ignited and the casing is expended. The resulting explosion propels the bolt head out of the gun at a high muzzle velocity. Then after a short amount of time the rocket engines on the bolt head kick in which accelerates the thing to even greater speeds.

It's kind of a hybrid between a regular firearm, a gyrojet and a grenade launcher.

This makes the most sense to me. Given that a bolter is said to have a calibre of 40mm (?), which is the same as modern day under-slung grenade launchers (at least in the British army anyway), the sole use of a powder charge in the casing wouldn't provide a particularly accurate shot due to the size of the round being affected by wind and gravity too much especially with the [lack of] length of the barrel. The addition of a rocket in the round itself would, at least in my imagination, keep the round on the desired trajectory and minimise the need to compensate by "aiming off". The use of a rocket in the round without a powder charge in a case would result in a fairly low muzzle velocity and would reduce the rate of fire of the weapon.

This is what I imagine a heavy bolter to be like but with rockets added to the rounds. Skip to 1:45 to see it bing fired

Rockets are inherently less accurate than conventional rounds due to the laws of physics.

In the case of rocket assisted artillery projectiles, you trade off accuracy for range, and your accuracy doesn't need to be pin-point anyway because a salvo of 155mm shells has a massive kill zone.

I thought they were more like 20/25mm rounds? 40mm doesn't leave a lot of space in the magazine. Astartes or not.

I kind of imagine bolters to be a bit like the 20mm gun the germans used at the end of Saving Private Ryan. But with much more explosive effects obviously. Or perhaps the AA-22 with the explosive rounds in.

A 20mm would be about the appropriate caliber, however I'd surmise that they probably wouldn't be any more "explosive" than 20mm, 20mm cannon shells are already explosive, and huge.

I mean here is a 20mm cannon shell next to a .50 BMG round (itself developed as an Anti-Aircraft/Anti-Materiel round), far more akin to something in the Autocannon range than the Bolter range.

I'd expect Bolters to probably be more akin to something like 25mm grenade, like the XM25 Grenade Launcher, that actually has very Bolter looking rounds.

I probably misread the calibre to be honest. It's been a while since I read that part of the fluff.

I reckon, 380,000 years in the future, engineering would have far extended our understanding, in other terms, si-fi.

But bolters do have shells. I have several HB models with shells around their feet.

 angelofvengeance wrote:
I thought they were more like 20/25mm rounds? 40mm doesn't leave a lot of space in the magazine. Astartes or not.

Depends on the pattern. Phobos patterns were stated as having 50mm calibre rounds where as the Tigrus and Umbra was something like 35mm rounds.

Also, not forgetting, that the Bolt Shells are supposed to have some sort of rudimentary Machine Spirit that guide the projectile in flight.

Yeh, bolter do have shells, its referenced in many books and in the ultramarines movie all bolters show shell casings hitting the floor

Whether bolter shells are caseless or not has varied wildly throughout the history of the books and codices.

Regardless, Insaniak is correct - even a caseless round will need ejecting occasionally to clear a jam or other misfire.

The actual calibre of bolter shells also varies in the background, but most Black Library and FFG books that I've read recently seem to place Astartes-calibre bolt weaponry as 0.75 calibre shells - making them ~ the same as 20mm cannon ammunition - not a million miles from the rounds fired from an attack helicopter's cannon.

It's ridiculously overpowered as a weapon to use on 'normal' targets (i.e. humans) but then it allows astartes infantry to engage other 'tough' targets - light vehicles, orks and other augmented humans and other alien monstrosities who are broadly immune to mere bullets.

Don't try and make sense of 40k universe...

One of these days I'll need to try and track down the "caseless bolter" thing. I can't remember seeing it in any of the aearly material (it was autoguns that were described as caseless in the original RT rulebook).

Mind you, as well as the "fluff varying" on the matter, it's equally valid to suggest that some bolters are caseless and some aren't. They don't all have to be the same.

Why do bolters have slides on both sides as well.

Modern grenade launchers still have a shell casing to eject. My understanding is that Bolt weapons are largely just efficient grenade launchers.

Because keeping gak straight is hard. Everything varies from author to author, aside from the fact that everyone wants to be an Ultramarine. The whole point of the Horus Heresy was that Horus was so mad he couldn't be an Ultramarine, he turned traitor. :