Equip a 10-man modern infantry force to beat a 40K space mar

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Mr. Oragahn
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Re: Equip a 10-man modern infantry force to beat a 40K space

Post by Mr. Oragahn » Sun May 04, 2014 3:59 pm

Lucky wrote:
Mr. Oragahn wrote: Still, as I said, by being self propelled, the bolter rounds still strike with more force than projectiles solely relying on their initial muzzle velocity. The perforation mixed to that constant thrust allows them to enhance the chance of delivering the damage inside the target.
All those grenade are powerful but won't get beyond the initial layer of protection.
However, what a bolter round gains in range, it loses in charge. Namely, the propellant takes the room that more explosive would take in the case of an explosive round fired from a grenade launcher (or, to a ligher caliber, from a slug fired by a shotgun).
I've never seen a bolt portrayed in a visual medium as being better then an equally large caliber slug thrower, and I'm not sure a bolter is used at a range that the fact it is has a rocket motor matters?
The rocket like design of a bolter round gives it the ability to cover more distance, perhaps striking the target at a faster speed as well the greater the distance covered, but by doing so it also trades mass (fuel reactant) for speed. Now in terms of energy, that's very good, because of E=1/2mv², but in terms of momentum where P=mv, mass is surely lost while waste doesn't ideally transform into energy, and air drag would still diminish v anyway if the projectile were inert.

Besides, my point was that an explosive will lose speed and trajectory coherence over a distance, but once it hits the target, if it's designed to trigger an explosion that propels a molten spike of metal forward for example, then the damage of perforation is ought to be considerably higher since most of the equivalent of fuel, but this time stored and kept whole during the entire projectile's trip, will be strictly used as an perforating charge.

Bolters are rather poor weapons at close range and very good to gain extra meters in range, however accuracy would leave much to be desired, but would surely manage to pin down an enemy at a far distance and with the round's design, no one aside an Ork would try to openly stand out because they'd still cause lots of damage.

An omnidirectional frag grenade, although of a heavier caliber of a bolter round I guess, wouldn't focus its energy on a single point. It really depends on the kind of target you're dealing with, quantity of targets, flocking, mobility, visibility, armour and distance.

It turns out to be very hard to say which is better unless you start running down the calculations.
But for our case here, since we've seen Space Marines go down to bolter fire but survive several shots from laser pistols, a bit less from laser rifles, we can more or less safely peg the kind of firepower that would be necessary for a 10-men squad to take one SM down.
Hevy Stubers are about as good as Heavy Bolters in the game stats. The idea that bolters are better then stubbers designed for the same task in any real way doesn't really hold water as they are used for the same thing at the same ranges in the fluff.
Stubbers' projectiles expand all their energy at launch. It greatly simplifies the estimation of their firepower. We know that air drag will be the main if not the single element of perturbation that would hamper the destructive ability of the weapon.
As seen above, it's not so easy when it comes to bolters.
For a similar round size, a bolter round would provide better range on the average but have a much lower muzzle velocity and turn out to be inferior on short range, only counting on a perforating head and some small quantity of explosive at the tip to provide good damage.
Assuming a heavy stubber would use explosive rounds with a AP tip, I'd pick the stubber any day considering the usual skirmish scenario you see SMs stuck in.
A boltgun is superior in that it appears most stub guns use the most basic kind of rounds. I don't find any mention of AP rounds.
Still, if heavy stubbers can harm SMs in game, I guess we can safely infer that our ten men shouldn't have many issues in taking that SM down.
Mr. Oragahn wrote: Besides, considering that Space Marines tend to engage targets at rather close ranges, the use of self propelled projectiles strikes me as odd.
In a way, it would be good if the projectiles would come with self-guidance systems. But that would require a level of refinement and technological might in advanced weapon systems simply not encountered within the IoM.
One should wonder why the IOM has so many projectile weapons used by planet hopping forces, and given the relatively small number of bolts a SM can carry when compared to how many he will need it is insane.
You've never seen the carts of ammo they tug? :)
Still, you're totally right, those clips are going to get expanded way too fast, and funny thing, while vanilla troops come with plenty of pockets and bags to carry ammo, this is hardly what you see a SM use.
Where do they store the numerous extra clips?

On another hand, this is funny:

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Lucky
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Re: Equip a 10-man modern infantry force to beat a 40K space

Post by Lucky » Sat Jun 21, 2014 1:25 am

Sorry for taking so long
Jedi Master Spock wrote: A lot of different ways. One of the key features of the Imperium is that local tech levels vary significantly. A lot of them are actually well under the level of modern technology. Not all worlds have the capability to produce supertech-level steel. Some of the worlds producing Leman Russ tanks are less advanced than our own in a lot of ways.
Wouldn't this be a reason to not use Imperial Guard equipment to judge Space Marine equipment?

Jedi Master Spock wrote: A lot of different ways. One of the key features of the Imperium is that local tech levels vary significantly. A lot of them are actually well under the level of modern technology. Not all worlds have the capability to produce supertech-level steel. Some of the worlds producing Leman Russ tanks are less advanced than our own in a lot of ways.

Another is that we know approximately the mass and velocity of ballistic projectiles that have the capability of threatening to penetrate the armor of these machines. This includes armor-penetrating discarding sabot rounds.

In particular, we know that the Vanquisher cannon fires an armor-penetrating sabot with a L/D ratio of about 3.5, based on diagrams in the appropriate Imperial Armour book. It's supposed to be depleted uranium, so the subcaliber sabot has a mass of about 10 kg.

The Earthshaker cannon fires a 38 kg shell at 814 m/s. Momentum is 30932 kg m/s.

The recoil of the Earthshaker is, unlike the recoil of the Vanquisher, dangerously high for the vehicle it is mounted on. This is in spite of the fact that the Earthshaker cannon is much larger (about 1.5 times as long and proportionately larger in all dimensions).

If the Vanquisher cannon had the same recoil energy as the Earthshaker cannon (with the Vanquisher cannon ~38% of the mass of the Earthshaker cannon), that would mean 19000 kg m/s of momentum for the shot.

Plug that back in for a 10 kg projectile, and you have a 1900 m/s velocity with an 18 MJ kinetic energy. (Ignoring the "discarded sabot" part of the round for the moment, which is significant).

This is applied over roughly a 40mm diameter circle (the diameter of the projectile is 1/3 of the 120mm caliber of the gun). This means that we have (right out of the muzzle) a momentum density of 15 meganewton-seconds per square meter, and an energy density of 14 gigajoules per square meter.

Compare to an M829A1 "silver bullet" penetrator. This has a 22mm diameter, 4.6 kg projectile, fired at 1575 m/s. Momentum density is 19 meganewton-seconds per square meters, and energy density is 15 gigajoules per square meter.

If we consider the fact that the sabot of the round is likely to weigh about as much as the penetrator (it's made from steel, not aluminum as the M829A1's sabot is) the momentum density drops by a factor of two (to 7.5 meganewton-seconds per square meter) and the energy density drops by a factor of four (to 3.5 gigajoules per square meter).

These are the two factors to consider if you're penetrating "conventional steel armor" (as opposed to weird physics-bending armor from some exotic material) - momentum density and energy determine whether or not you punch through.
Imperial Armour Vol I wrote: Such is the power of the gun and the sophistication of the ammunition that there is no known armour a Vanquisher cannon cannot penetrate, even the thick armour of a Titan can be punctured.
The penetration of a M829A1 is 670mm at point blank.

We can fiddle around with the parameters of the Vanquisher cannon all we like, but as long as we actually pay attention to the underlying physics, it's not appreciably better, and it can pierce the armor of a titan, much less a Land Raider, and a Land Raider's armor is listed as equivalent to maybe 300mm of conventional steel.

When you come down to it, we have no reason to assume that "conventional steel" in the Imperial Armour books means anything really different from what it would if we happened across it in Jane's.
0) I'm not familiar with Newtons. Is there a less technical way to describe the information? It can be rather hard at times for me to visualize numbers and uncommon measurements.

1) Isn't it a large part of the setting that all Imperium of Man equipment is becoming lower and lower quality, and is also unwilling to admit things are getting worse meaning that any stats given may be unreliable?

2) Haven't Tempest Land Speeders defeated Titans before? If this is correct then is destroying a titan really impressive?

Jedi Master Spock wrote: A lot of the bulk has to be, but it doesn't take a lot of thickness of stuff five times as tough as conventional steel to go a long way, and it's also lighter than steel.

Realistically speaking, there's a pretty big range. An anti-materiel rifle might be plenty; or, on the other end, the original Mark I bazooka might not be quite enough. We can't really say from the evidence on hand.
1) I seem to recall high quality IOM steel being worked by hand in a thread in a different part of the site?

2) This picture might give some insight into how thick Space Marine armor is: http://wh40k.lexicanum.com/wiki/File:Mk ... 5_tLxxnaZQ
Jedi Master Spock wrote: Hundreds of megajoules is still a lot of energy. The heavy weapons I've been talking about using - recoilless rifles, RPGs, etc deliver a few megajoules to the target. The Javelin has a warhead that delivers several tens of megajoules to the target.

Even if it's a relatively large caliber weapon for its size, the lascannon delivers a lot of energy to a relatively small point.
Sorry, my point was somewhat irrelevant to the conversation at hand. I was talking about analysis in general as something can at times seemingly exceed what it is suppose to be able to do as well as the opposite do to factors that can not be an anticipated.

Jedi Master Spock wrote: They're not a sure kill in all of the game systems. I would credit it to them being shaped-charge rounds, or possibly being charges that fire a penetrator point blank. Focusing the energy tightly makes a world of difference in piercing armor.
The lances are described as effective if they hit so that would give a vague idea as to what is actually needed to defeat an armored vehicle 40k, and bolts are suppose to penetrate before exploding..



Jedi Master Spock wrote: Watch film that's supposed to be showing actual bullets (but is produced fictionally), and you'll see a similar speed. Even outside of the Matrix movies with their "bullet time." We just can't read too much into visuals of bullet-like objects flying - in order for us to perceive the effect of motion of a bullet on a human scale, it needs to be relatively slow.
I'm not sure that I'm understanding what you are saying, but it sounds like: "Bullets are sometimes misrepresented in visual media so we should all projectiles are always misrepresented,", but that doesn't sound right?


Bolts are rockets, and rockets start slow, and then execrate. This is why gyrojet guns make poor close range weapons, they need time to accelerate. What i'm seeing in the examples I provided are visuals that are constant with the real counterparts.

Jedi Master Spock wrote: I would disagree. I don't think infantry having / using heavy weapons (recoilless rifles and the like) is particularly out of the ordinary.
The thing is that if a remotely operated system is used then the Space Marine won't know where the enemy is. I.G. mortars don't seem to be remotely operated, and the closest thing I can think of is Tau drones which are effective even though they seem to use direct fire weapons.
http://wh40k.lexicanum.com/wiki/Mortar#.U6FpQxyXD9k

+++++

XM-1049 round fired from a XM-109 or XM-307 seems like it might be useful in this scenario? A 20 x 83.5 mm MG151 fired from a Denel NTW-20 might be better. They seem to at least be similar to Heavy Stubber. Perhaps I'm misunderstanding something as firearms aren't my specialty?
http://www.youtube.com/watch?v=vXLRYf9EV2Y

http://www.globalsecurity.org/military/ ... 7-25mm.gif

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