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Are any instances in the fluff of these weapons -or any of the other high-AP xenotech weapons out there- shooting through multiple people in one shot?

A lascannon being a laser would probably stop after the first impact based on laws of physics regarding lasers...idk though and I am no expert so take that with a grain of salt if you must. Just my $0.02

I would imagine against regular humans the air being vaporized would kill them regardless (book I have lists a melta as a very good room clearer). As far as general penetrance, if fired at blank point I would guess it could penetrate 2 or 3 humans, maybe more unarmoured. For fluff for the numbers, just my general estimate.

Alright. Fluff varies from source to source and IRL physics not withstanding, I choose to use FFG RPG stats for my response.

The Workings:


The Summary (Average Guardsmen punched through):

Lascannon -
2 (Doesn't get through the back-plate of the 2nd Guardsman)

Meltagun -
1 (Penetrates the armour of the 2nd Guardsman and takes a third of his health. Short range bonus doesn't change the number, damage is the same and still gets soaked even with increased pen.)

Leman Russ Vanquisher Cannon -
1 (Takes half health off 2nd Guardsman).

Plasma Cannon (Max) -
1 (Takes half health off 2nd Guardsman).

Note that these don't take into account extra effects such as Plasma Cannon splash or Meltaguns flash-scorching lungs or Cannon overpressure effects that would cause more casualties.

Las cannons are supposed to be able to do damage to heavily armored vehicles, I'd consider their "shoot through" potential to be much higher than two guardsmen.

Similar case with melta, albeit the effects being a bit different.

I'm thinking about how many people a typical modern tank round can punch through, without even slowing down. I'd say at least that for the lascannon, as it is a highly concentrated beam designed to pen thick (and advanced) armor.

Melta would probably have less "penetration" in this case, but would simply burn through the entire target. My theory in this case is that while it would go through less guardsmen, it would probably be more effective (completely vaporizing them as opposed to simply blasting them in half.)

(...and before anyone says it, yeah I'm using a more "what I'd imagine the real thing" doing assessment as opposed to comparing in game stats and such)

I don't know if comparing a Lascannon to a tank round in this case will work.

I have no real idea how physics work when it comes to energy, but I'd want to know the kinetic force behind the shot? I know we do have lasers being developed and introduced into our military on ships and from what I understand they work based off of heat and not so much kinetic force. One of these is rumored to be able to cut through 20 inches of steel in about a second or two.

When you compare this to a tank rounds you'd have to be a lot more specific as there are several different types of tanks rounds that we shoot, mpact, mpact air, ordinance reduction, heat rounds, sabot, etc.

For the sake of this comparison though lets go with the Sabot. It's the anti-tank round fired by the Abrahams. It is made from depleted uranium which is incredibly dense. Its fired from a 120mm cannon (to give you an idea of size), the casing burns up and petals fly off, so basically you're left with a couple of feet of depleted uranium traveling at about 5500 feet per second. It's basically a super heavy spear going really fast. The kinetic energy behind the round is what does the damage. Mainly because of its speed and the fact its one of the most dense compounds on the planet, up there with tungsten. I've seen these shot through at least a few hundred meters of mud brick walls. If you haven't been around these they are incredibly hard, like concrete. That doesn't even get into the modified Sabot rounds that I've seen penetrate the front armor of a tank and blow the engine out the back for several meters. These rounds would go through double digit number of regular guardsman at minimum. Even the OR round (which is more or less a shotgun) would penetrate several guardsman since they are designed to destroy things like tank traps/barricades and can/have been used very effectively to destroy enemy troops behind said barricades. It would obviously be less if going through regular power armor but i still think it would be able to go through more than one with a direct hit, the sabot at least.

I don't think a laser would work the same way once it made contact with the first object. Someone correct me if I'm wrong though.

 ILegion wrote:
I don't know if comparing a Lascannon to a tank round in this case will work.

I have no real idea how physics work when it comes to energy, but I'd want to know the kinetic force behind the shot? I know we do have lasers being developed and introduced into our military on ships and from what I understand they work based off of heat and not so much kinetic force. One of these is rumored to be able to cut through 20 inches of steel in about a second or two.

When you compare this to a tank rounds you'd have to be a lot more specific as there are several different types of tanks rounds that we shoot, mpact, mpact air, ordinance reduction, heat rounds, sabot, etc.

For the sake of this comparison though lets go with the Sabot. It's the anti-tank round fired by the Abrahams. It is made from depleted uranium which is incredibly dense. Its fired from a 120mm cannon (to give you an idea of size), the casing burns up and petals fly off, so basically you're left with a couple of feet of depleted uranium traveling at about 5500 feet per second. It's basically a super heavy spear going really fast. The kinetic energy behind the round is what does the damage. Mainly because of its speed and the fact its one of the most dense compounds on the planet, up there with tungsten. I've seen these shot through at least a few hundred meters of mud brick walls. If you haven't been around these they are incredibly hard, like concrete. That doesn't even get into the modified Sabot rounds that I've seen penetrate the front armor of a tank and blow the engine out the back for several meters. These rounds would go through double digit number of regular guardsman at minimum. Even the OR round (which is more or less a shotgun) would penetrate several guardsman since they are designed to destroy things like tank traps/barricades and can/have been used very effectively to destroy enemy troops behind said barricades. It would obviously be less if going through regular power armor but i still think it would be able to go through more than one with a direct hit, the sabot at least.

I don't think a laser would work the same way once it made contact with the first object. Someone correct me if I'm wrong though.

Going to start out by saying, I like your info here.

(By the way, not arguing here, just elaborating on some of my previous theories)

My theory with the lascannon is that it being a laser, material density would likely be the primary factor in penetration. My thinking is that human bodies (even armored ones) are going to be significantly less of a barrier to a laser beam than tank armor of any sort. I think comparing it's effectiveness to a sabot is probably the closest we can get, as both a laser beam and a sabot lack an explosive charge (typically, I know modern HEAT/Squash Head/whatever round I'm currently forgetting currently do) , and any "boom" is caused by the impact, or in the case of a laser sudden and violent increase in temperature. (also the Lascannon/Sabot round's purposes are similar, take down enemy armor)

Melta is similar, being a heat based weapon (albeit, rather than concentrated light it is super heated air), but not the same.

Meltas are frequently pictured as being similar to a flamer in the fluff, though of course it's much denser and dangerous. What it does is forcing molecules into a state of plasma in the path of the beam. This indicates no molecules without a crazy heat resistance should be able to withstand it and thus it becomes a semi flamer with a very small but very deadly ray. It's actually fairly well portraited in the video games fire warrior as well as Space marine.

Lascannons are essentially a big lasgun. Las weapons work like big magnifying glasses. Ever played with one? It heats up an area and burns it through condence light. In modern day it's employed in some surgery, if you've come across it it's probably in pinpple removal. How it works is that it hits an area and fries it of, essentially turning it to gas (or vapor, hence the term "vaporised" often being used). A lasgun that hits a person clauterises the wound but leades to severe internal body damadge. You don't bleed out, you bleed in. The lascannon is the same but bigger and would not pass through it's first target. It behaves like light so will stop at the first thing it "illuminates"(/vaporises). The sheer size of the hit carries lots of stopping power though, as well as penetration depending on how long a surface is exposed to the beam. Pretty well portraited in dawn of war 1 Guards heavy weapons team.

Haha thanks Cothonian. I try. And i get what your saying. I was thinking more along the lines of Nerak (i think i learned about this in college haha). But once light hits a target it disperses so even though a Lascannon would cook the gak out of a guardsman, possible those standing right beside him, it may not actually penetrate far.

I imagine the reason they can blow up tanks is simply because they overheat the whole thing at which point ammo/fuel start cooking off which is what causes the explosion like you said. I dunno though.

I think it's funny though because i'm pretty sure this conversation is being hashed out in RL now.

https://defensesystems.com/articles/2016/06/28/navy-150-kilowatt-laser-weapon-test.aspx



Automatically Appended Next Post:
Seems like errybody wants a laser...

In Dead Men Walking, Kriegsmen Grenadiers throw themselves at Necron Flayed Ones to allow their comrades using Melta guns to melt both the robot and the man, and it worked. So I am guessing it would go through at least a SM + a Guardsman.

 Drummernathan wrote:
A lascannon being a laser would probably stop after the first impact based on laws of physics regarding lasers...idk though and I am no expert so take that with a grain of salt if you must. Just my $0.02

Lasers make terrible weapons for penetrating things if you look at actual physics. The heat generated by the light would kill a human or a tank long before you got much penetration.

 Exergy wrote:

 Drummernathan wrote:
A lascannon being a laser would probably stop after the first impact based on laws of physics regarding lasers...idk though and I am no expert so take that with a grain of salt if you must. Just my $0.02

Lasers make terrible weapons for penetrating things if you look at actual physics. The heat generated by the light would kill a human or a tank long before you got much penetration.

I was under the same understanding (actually reflected in the game by lasguns having ap- ), however I assumed they get around this fact through beams of measured lenghts to "work through" an outer defensive layer.

Lasguns have AP - but Hotshots have AP 3, and it feels to me Hotshots are meant to be hotter

This Scientific American article tells us it takes roughly 3 gigajoules to vapourise a human body. That same energy can apparently melt 5,000 pounds of steel.

I suspect though that a lascannon wouldn't 'penetrate' a humanoid target but instead dump all of it's energy into said target, resulting in a violent, messy explosion of steam and gore. Assuming of course it's a packet of energy and not a beam, because if they're beams then focusing one against a stationary target (or just keeping it on a moving one if you can) should do phenomenal damage. Beams would also render any sort of horde or swarm army invalid. Just set your lascannon on a tripod, put it on 'low' power and start sweeping it across the advancing horde.

 Kojiro wrote:
This Scientific American article tells us it takes roughly 3 gigajoules to vapourise a human body. That same energy can apparently melt 5,000 pounds of steel.

I suspect though that a lascannon wouldn't 'penetrate' a humanoid target but instead dump all of it's energy into said target, resulting in a violent, messy explosion of steam and gore. Assuming of course it's a packet of energy and not a beam, because if they're beams then focusing one against a stationary target (or just keeping it on a moving one if you can) should do phenomenal damage. Beams would also render any sort of horde or swarm army invalid. Just set your lascannon on a tripod, put it on 'low' power and start sweeping it across the advancing horde.

a beam would soon start running into vaporized gunk. Lasers can only transmit through relatively clear space. Air doesnt absorb much light, hence we can see through it. But start heating up/burning/vaporizing armor, clothing, flesh and you get lots of steam and smoke that lasers cannot penetrate. Then the beam will just end up heating the steam/smoke more and not ever reaching the target.

Depends on if the author remembers that diffusion due to flash-vaporization of blood and body matter is a thing.

In a BL novel, enforcer/SWAT style units carry lascannons on yokes around the waists of their carapace armor and use them as antipersonnel weapons. These heavy weapons troopers are called dervishi. I think the book is Lord of the Night.

This is as far as what the Imperium have actually managed to get lasers to do, in terms of shooting infantry.

 Exergy wrote:

 Drummernathan wrote:
A lascannon being a laser would probably stop after the first impact based on laws of physics regarding lasers...idk though and I am no expert so take that with a grain of salt if you must. Just my $0.02

Lasers make terrible weapons for penetrating things if you look at actual physics. The heat generated by the light would kill a human or a tank long before you got much penetration.

The mistake here being, of course, trying to relate 40K sci-fi weaponry to how RL laser beams behave. A real laser is simply a beam of light. This is quite obviously not the case for 40K las weapons. Just as Star Wars lightsabers are not literally blades made of light. It's just their name.

Long story short; don't look at actual physics when pondering space fantasy concepts. It rarely provides anything useful.