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Posted: 2006-02-26 07:25pm
by Batman
Knife wrote: Ok. But still, a spear isn't a rifle round either.
No it isn't. On the other hand rifle rounds don't pick up people and throw them several metres, either.
About the only advantage the rifle round has over that spear is speed. Would that make that much of a difference?

Posted: 2006-02-26 07:27pm
by Sea Skimmer
Batman wrote: About the only advantage the rifle round has over that spear is speed. Would that make that much of a difference?
Increased velocity has a far greater effect on projectile energy and penetration then increased projectile mass. That's why discarding sabot works so well for AP tasks.
Batman wrote: No rifle ever manufactured includes ammunition. It comes seperately, hence the evolution known as loading. Your reasons for the impossibility of 5.56x45 HEDP would be?
The fact that the smallest fuses we can make are the size of the entire bullet. That doesn't leave much room for minor stuff like the explosives, the void space, the liner, the wrapping of ball bearings and the casing to hold all the shit together while its fired out of the rifle. 5.56mm HEDP is totally impossibul.

Posted: 2006-02-26 07:35pm
by Batman
Sea Skimmer wrote:
Batman wrote: About the only advantage the rifle round has over that spear is speed. Would that make that much of a difference?
Increased velocity has a far greater effect on projectile energy and penetration then increased projectile mass. That's why discarding sabot works so well for AP tasks.
That's what I get for asking a stupid question.
The question is how much greater as for the mass of the projectile we're talking about it's in excess of three orders of magnitude IIRC compared to modern rifle rounds. Somehow I doubt that spear was travelling at less than a meter a second.

Posted: 2006-02-26 07:45pm
by Sea Skimmer
Cykeisme wrote: Btw, I'm just curious.. what's the mechanical accuracy of an issue M16A2 with issue ammo (in minutes of angle) at 500m, anyway?
An accuracy rating in minutes of angle is a fixed value, range doesn’t matter. Now realistically, accuracy drops off considerably at long range, but that’s because of variable weather conditions. Artillery units and modern tank guns have elaborate sensor and computer setups to compensate for said weather conditions, but that isn’t exactly an option for a rifleman. All he has is a limited degree of windage and elevation control plus his brain and Mk1mod0 eyeball.

Anyway, a typical M16 that has been used is accurate to about nine mils. Given modifications and tight control over the gun, you can get that down to .5MOA but the rifle isn’t able to hold that kind of accuracy for many rounds. One MOA is equal to approximately a 1 in 1000 error. So a typical M16A2 firing to 800 meters will be accuracy to within about 7.2 meters of the aimpoint.

Posted: 2006-02-26 07:59pm
by Elheru Aran
Knife wrote:
Elheru Aran wrote:If the shrapnel managed to make its way through the body glove? Sure. Otherwise it's more likely to just make a few nicks in the armour. You'd need something more like a LAW or RPG, direct hit, to blast through the armour.
I assume that ST armor is designed to either deflect or mitigate the damge done by a blaster. I'm not so sure you can translate that to bullet proof. There might be something in the EU about it, but I can't think of one.

Having an arrow bounce off of it is a bit different than a .223.
Didn't say it was bullet proof. Said it's likely more or less shrapnel proof. I should've quoted the post I was replying to...
Kartr_Kana wrote:How would the M203 do against stormies? If blasters do the damage of a small grenade wouldn't the M203 be able to kill them?
In this respect it's more like modern Level III- IV armour IMO, in that a heavy enough shot will likely penetrate it, but it should protect from lighter weapons and shrapnel. Whether shrapnel penetrates depends on how close and how powerful the explosion is...

Posted: 2006-02-26 08:08pm
by Cykeisme
The OP should have cut to the chase and asked how Star Wars troopers compare with modern soldiers. The main site deals with this in considerable detail, so perhaps it would do the original poster well to read through it throroughly.


Can one of the more knowledgeable folks (collisions, materials science, etc) come in and give us a more definitive answer about what the resistance of the spear that lifted the stormie backward can tell us about its effects on bullets?

Anyway, a large portion of casualties sustained by infantrymen in conventional warfare are caused by shrapnel rather than hits from direct fire.
By covering the user in hard armor, you effectively shrink the effective casualty radius of weapons that rely on fragmentation effects, and depending on the weapon, in some cases statistically negating their statistical effectiveness.

They'd be resistant to infantry-packed explosive/fragmentation weapons and possibly bullets, and combined with the power of blaster weaponry (and I mean a full range of T-21s/DLT-19s, E-Webs and E-11s to match M16s, M4s and M249s, M60s and M2HBs), I don't think the modern guys match up well at all.

Re: Star Wars small arms weak?

Posted: 2006-02-26 09:57pm
by The Dark
Batman wrote:
PayBack wrote:Given time I'll make an effort to fine evidence of people questioning the stopping power of the 5.56 round at that kind of range.
I'd be very interested in that. I would be rather surprised if heavy clothing makes much of a difference for standard ball/FMJ rounds at any ranges worth considering but I've been wrong before.
The Box O' Truth did do a test using denim and terry cloth. They found that the .223 used in the AR-15 did go through the cloth. However, the firing was at extremely close range, and the bullet was sideways by the time it was through the cloth, meaning its surface area upon striking would be expanded, reducing penetrating power but widening the wound channel. They did find thick clothing will definitely stop a JHP from expanding.

Posted: 2006-02-26 11:15pm
by PayBack
Silly as it is for me to counter a post backing me up. It would be dishonest of me not to point out that AFAIK he wasn't using SS109 rounds like NATO use, and they penetrate better than standard .223 rounds.. but then in defence of my position, that penetration is at the cost of lethality.

Posted: 2006-02-27 01:32am
by Master of Ossus
Batman wrote:I can't for the life of me find the relevant threads right now but there WAS extensive discussion about that (a spear thrown by a droid so hard it lifted a Stormy off his feet and threw him several metres without so much as denting the armor. IIRC it was from one of the YJK books), so I think we can safely assume .223 or even .308 won't penetrate Stormie armor.Wether or not they do damage via momentum transfer is a wholly different ballgame.
It's from Mike's Hate Mail page. IXJac argued with him that the rifle round is a better penetrator. He was wrong.
Mike Wong wrote:Let's say you're wearing rigid armour with no travel, and a projectile hits you with 10 kg*m/s of momentum. In order to determine the reaction force, you need to figure out how long it will take to stop (let's neglect your own acceleration, since it will be negligible compared to the bullet's velocity). In this idealized scenario, the armour doesn't deform at all, so the entire deceleration zone must be in the bullet itself. Suppose the tip squashes so that the bullet becomes 6 mm shorter during the impact (I just made that figure up; if you're a firearms geek, I'm sure you can get more accurate figures). This gives you 6 mm of deceleration space, and if the initial velocity was 1000 m/s, you have all the information you need. Simply remember that displacement = ½at², perform some substitutions, and you'll find that the bullet must stop in roughly 12 microseconds.

Divide the momentum by 12 microseconds, and you'll find that you need to apply more than 800 kN to stop that bullet! That's a bit higher than IXJac's 10 N figure, isn't it? Now, let's go back to that 3 mm wide impact area. The bearing stress on that area would be 800 kN divided by 7E-6 m², or more than 100 GPa! Since the strongest alloys in the world can handle less than 2 GPa, it's no wonder a rifle bullet will put a dent in just about anything, eh? But in order to punch out a hole clean through the plate, you've got to do a bit more work. You need shear out an 8 mm wide hole (wide enough for the 7.62mm bullet to pass through), and if it's a 5mm thick plate, the load-bearing area is roughly 18 times larger, so the shear stress drops to about 6 GPa. Unfortunately, this is still too large, which is why you need a bit of "give" in your body armour.

Realistically, the armour doesn't fit perfectly on your body. Moreover, your body is not rigid (even the armour isn't rigid). The combination of body armour, thickness, and deflection, in conjunction with your body's temporary deformation will all add some breathing room (let's say 1.5 inches). This would increase the deceleration zone from 6 mm to 44 mm, thus increasing the deceleration time from 12 microseconds to 88 microseconds. The reaction force would drop from 800 kN to 114 kN, the bearing stress would drop to 16 GPa, and the shear stress would drop to less than 900 MPa, which is within the limits of modern steel alloys. Mind you, this is still an idealized analysis; I am neglecting the effect of bending moment and the time of travel through the armour, both of which would further decrease the load. Moreover, I am using a fixed deformation on the part of the bullet, when realistically, you must compare the bullet's mechanical strength to the armour's mechanical strength to see which one will take the brunt of the damage. As I mentioned before, high speed photography shows rifle bullets disintegrating upon impact with very hard armour, so virtually all of their KE actually ends up going into self-destruction.

In the case of the spear-throwing incident, the tiny nick on the armour indicates that it is much stronger and tougher than the metallic spear, otherwise there should have been more damage. The human brain can withstand up to 300 G's of transient (as opposed to sustained) acceleration without injury, and the subject nearly lost consciousness from the impact against the far wall despite his padded helmet, so it seems likely that he was near the threshold. If we assume 1 inch of deflection from the helmet padding (which you can see in the SWVD), this means his head must stop in roughly 4 ms, and he was moving at speeds of up to 12 m/s, even if we disregard the braking effect of his feet sliding across the floor beneath him before impact. This gives him around 1000 kg*m/s of momentum (assuming 80 kg body weight). Even if the spear's mass was quite large (say, 10 pounds), it would still have to be moving at 220 m/s (around 500 miles per hour!) in order to send him flying backwards so violently. Small wonder they used a robot instead of a human to throw the spear, eh? Given the same 44 mm deflection, the reaction force exceeds 2.5 MN (although according to IXJac, force is completely irrelevant ... snicker). When you plug these figures into the equations used above for the bullet, keeping in mind how little damage was done to the armour and what a tiny contact area the "nick" would have been, you will see why I concluded that stormtrooper armour can deflect small-arms fire, even if it wasn't intuitively obvious to you before.

And now for the $64,000 question: how are you supposed to perform these analyses using only kinetic energy? The KE balance would indicate that either projectile carries dozens, perhaps hundreds of times as much energy as it needs to do the work, so now what? Any ideas? Would IXJac deign to explain his wondrous methods to us? Energy balances do not tell us anything about what happens during a process. They only help us determine limits, and we can use them for correlations, but they're not magic. You still need to do old fashioned mechanical analysis if you want to figure out what will happen during the process.
The whole discussion's worth reading. Mike goes into a little more detail, in other places, but basically if the armor can stop the spear from penetrating it can stop a NATO round.

Posted: 2006-02-27 07:08am
by Batman
Drat. Never thought of checking the Hate Mail section. Thanks, MoO.

Posted: 2006-02-27 09:11am
by LaserRifleofDoom
About blaster accuracy:
"Inherent instabilities limit the ability to precisely aim a blaster bolt, but knowing one's weapon well can strengthen marksmanship" ~ Visual Dictionary, pg 7.

So the blaster is an inherently innacurate weapon, though presumably a stormtrooper can overcome that.

Posted: 2006-02-27 09:18am
by VT-16
I can't for the life of me find the relevant threads right now but there WAS extensive discussion about that (a spear thrown by a droid so hard it lifted a Stormy off his feet and threw him several metres without so much as denting the armor.
In Empire Issue 16 to 18, Amanin warriors apparently throw spears that penetrate both stormtrooper armor and the flesh on the inside.

They got big-ass arms, though. :P

Posted: 2006-02-27 03:49pm
by consequences
LaserRifleofDoom wrote:About blaster accuracy:
"Inherent instabilities limit the ability to precisely aim a blaster bolt, but knowing one's weapon well can strengthen marksmanship" ~ Visual Dictionary, pg 7.

So the blaster is an inherently innacurate weapon, though presumably a stormtrooper can overcome that.
I can make precisely the same claim about an M16, and thanks to the research done by others in this thread, immediately provide numbers to back it up. Got anything other than hyperbole?

Posted: 2006-02-27 11:26pm
by Connor MacLeod
LaserRifleofDoom wrote:About blaster accuracy:
"Inherent instabilities limit the ability to precisely aim a blaster bolt, but knowing one's weapon well can strengthen marksmanship" ~ Visual Dictionary, pg 7.

So the blaster is an inherently innacurate weapon, though presumably a stormtrooper can overcome that.
That's assuming a "plasma bolt/particle beam" nature for the blaster weapon, though. And it doesn't say it is "inherently inaccurate" it just less precise a weapon compared to other kinds (like a laser rifle.)

Posted: 2006-02-27 11:33pm
by Connor MacLeod
Regarding the Young Jedi Knight thing with the spear-throwing incident:

1.) it wasn't by a droid. It was by a guy equipped with a droid arm, IIRC. It still did pretty much what Mike described, however.

The KE of the spear in question (with the momentum involved) carries substantially grreater KE on a "per hit" basis than rifle rounds.


2.) In "Tattooine Ghost" stormtroopers are hit with rifle fire from Tusken raiders that physically knocks them on their ass (implying substantial momentum behind the bullets), yet it only penetrates weak points like the eyeholes.

3.) From the novel "shatterpoint" its well known that even low-tech backwaters like the planet Mace visited can access hypersonic projectile weaponry (which blasters are superior to, I might add.)

Its also noted that stormtrooper armor does incorporate some form of shielding and "Heat/energy sinks" (the ANH novelization and the OT Visual Dictionary, IIRC.) for absorbing and minimizing the lethality of energgy weapons.

Posted: 2006-02-27 11:42pm
by brianeyci
Batman wrote:Drat. Never thought of checking the Hate Mail section. Thanks, MoO.
Ah this brings back memories. When I first got here I demanded evidence that stormtrooper armor could stop bullets, and got the spear => bulletproof answer along with a "let's see if he gets it" snicker from probably you and a couple others...

...I either kept my mouth shut or looked through the hatemail page, one or the other. Darkstar's metal spine was really the highlight of it all.

Brian

Posted: 2006-03-01 05:36pm
by Lazarus
So stormtrooper rigid plate armour can stop bullets, fair enough, but no matter how effective that armour is at stopping projectiles, if a rifle grenade goes off near a stormie, the concussive force should surely at the very least incapacitate the guy inside the armour, and more likely rip a few limbs off? I know the shrapnel is the more deadly part over a wider area, but still...
It'd still go with an M4 comparison. That is also a carbine that front line troops are issued. Neither the MP5 nor the MP7 are for front line troops (though with the MP5 I'm leaving myself open because yes they're used by special forces but generally for anti terrorist work, not on the battlefield). The MP7 is for rear area troops for whom carrying a carbine like the M4 is inconvenient.
AFAIK, the MP7 is really more of a large machine pistol, like a Mac 11 or something, I know you CAN extend the stock and use the vertical grip, but its still a machine pistol at heart, especially with the 20 round mag in instead of the more cumbersome 40 round version. Plus, the size of the actual body is quite a bit shorter than an E-11, or indeed an MP5. I've also yet to see a scope mounted on an MP7 (not an RD), while scopes are frequently claw mounted on MP5's, similar to the scope found on E-11's in fact...
I actually hadn't noticed anyone ever holstering an E-11. I know that the stormies seen in ANH do have holstered weapons, but in the Visual Dictionary photo this weapon isn't an E-11, its some form of smaller weapon, actually none too disimilar to an MP7! If you'd care to point out the part where the E-11 is seen holstered, fine, but I would think it highly impractical to do such a thing (I'd never be able to holster my MP5!).
Having also handled an M-4, the weapon is quite a bit bigger than the MP5-A5 (in relative terms), and although a carbine, is much closer to a rifle than the MP5 is. As a weapon, its also much bulkier.

Posted: 2006-03-01 07:50pm
by Cykeisme
Lazarus wrote:So stormtrooper rigid plate armour can stop bullets, fair enough, but no matter how effective that armour is at stopping projectiles, if a rifle grenade goes off near a stormie, the concussive force should surely at the very least incapacitate the guy inside the armour, and more likely rip a few limbs off? I know the shrapnel is the more deadly part over a wider area, but still...
Rip a few limbs off? You are vastly overestimating the yield of an M203's 40mm grenade.

There's actually a relatively tiny amount of explosive inside fragmentation grenades (both launched and thrown). The grenade is specifically designed to convert a maximum amount of chemical energy (in the explosive charge) into kinetic energy in the fragments. The concussion is almost insignificant in comparison to the shrapnel.
The weapon just isn't designed for taking on hard targets.

Posted: 2006-03-01 11:11pm
by Elfdart
Lazarus wrote:
It'd still go with an M4 comparison. That is also a carbine that front line troops are issued. Neither the MP5 nor the MP7 are for front line troops (though with the MP5 I'm leaving myself open because yes they're used by special forces but generally for anti terrorist work, not on the battlefield). The MP7 is for rear area troops for whom carrying a carbine like the M4 is inconvenient.
I actually hadn't noticed anyone ever holstering an E-11. I know that the stormies seen in ANH do have holstered weapons, but in the Visual Dictionary photo this weapon isn't an E-11, its some form of smaller weapon, actually none too disimilar to an MP7! If you'd care to point out the part where the E-11 is seen holstered, fine, but I would think it highly impractical to do such a thing (I'd never be able to holster my MP5!).
Having also handled an M-4, the weapon is quite a bit bigger than the MP5-A5 (in relative terms), and although a carbine, is much closer to a rifle than the MP5 is. As a weapon, its also much bulkier.
Luke and Han both have holstered E-11s when they bring Chewie into the cell block on the Death Star. You can see them slowly drawing them as they talk to the guards. In TESB, the two "MPs" who pick up Captain Needa's corpse also have holstered E-11s.

I always likened the E-11 to the M-1 Carbine, the larger blasters (the ones the clonetroopers carried, the ones Chewie and the sandtroopers use in ANH) as the equivalent of M-1 rifles, and the T-21 to the BAR or Bren.

Posted: 2006-03-01 11:27pm
by Knife
Lazarus wrote:
I actually hadn't noticed anyone ever holstering an E-11. I know that the stormies seen in ANH do have holstered weapons, but in the Visual Dictionary photo this weapon isn't an E-11, its some form of smaller weapon, actually none too disimilar to an MP7! If you'd care to point out the part where the E-11 is seen holstered, fine, but I would think it highly impractical to do such a thing (I'd never be able to holster my MP5!).
Luke, and Han, the whole time they're in Stormtrooper armor, have their E-11's hostered when called for. AFAIK, in ESB and RotJ, they use them as primary arms, however in ANH, the E-11 is almost a side arm.
Having also handled an M-4, the weapon is quite a bit bigger than the MP5-A5 (in relative terms), and although a carbine, is much closer to a rifle than the MP5 is. As a weapon, its also much bulkier.
An M-4 is only marginally smaller than the full sized M-16. A collaspable stock make the difference. In ANH it's not like the E-11 was a derringer, more like a long forgotten longgun. It was one hell of a holster, but they were holstered.

Posted: 2006-03-02 01:27am
by PayBack
Knife wrote: An M-4 is only marginally smaller than the full sized M-16. A collaspable stock make the difference.
Though apparently the slight difference in barrel length makes a hell of a difference in lethality.

Posted: 2006-03-02 01:49am
by Cykeisme
Hmm.. ESB and RotJ take place mostly in indoor (or shipboard) and heavily wooded environments, so it's not surprising that the troops would be armed with carbines. In ANH, on the open deserts of Tatooine, we see T-21s and DLT-19s. The fact that we see more E-11s is an effect of the terrain that appears in the movies, than the popularity of the E-11.

Knife wrote:An M-4 is only marginally smaller than the full sized M-16. A collaspable stock make the difference.
The length of the barrel makes part of the difference too, doesn't it? Is that not the idea for having a carbine in the first place.. shortening the barrel to ease handling of a firearm in confined areas?
PayBack wrote:Though apparently the slight difference in barrel length makes a hell of a difference in lethality.
There are some who are of the opinion that 5.56 NATO is already underpowered. Shortening the barrel length of the M4 results in lower velocities. Considering 5.56 NATO is a lightweight round that relies on high velocity to cause effect to the target, this exacerbates the (perceived?) problem significantly.


Anyway, I suppose that due to differences in their actual natures, there are some limits to the parallels we can draw between blasters and modern firearms.

Posted: 2006-03-02 02:23am
by Cykeisme
A li'l trivia.

The Wikipedia entries on the M16 and M4 state that an M4 with the stock collapsed is 28.9", whereas an M16 is 39.4" in length, a dif.

Since 5.5" of difference comes form the barrel length difference (14.5" and 20"), the collapsible stock saves 5". So roughly half the length difference is from the barrel, and the remainder is from the retractability of the collapsible stock.

Posted: 2006-03-02 12:32pm
by SVPD
PayBack wrote:
Knife wrote: An M-4 is only marginally smaller than the full sized M-16. A collaspable stock make the difference.
Though apparently the slight difference in barrel length makes a hell of a difference in lethality.
Remember, however, that the 5.56mm round is not necessarily designed for maximum lethality. To the best of my understanding, it's designed to be incapacitating (it still exceeds the velocity of any handgun round), but not necessarily lethal.

The idea is that if someone is incapacitated but still alive, someone else will stop fighting to render aid, effectively taking 2 or 3 guys out of the fight with 1 hit.

Posted: 2006-03-02 01:15pm
by Lazarus
Luke and Han both have holstered E-11s when they bring Chewie into the cell block on the Death Star. You can see them slowly drawing them as they talk to the guards. In TESB, the two "MPs" who pick up Captain Needa's corpse also have holstered E-11s.
Now you come to mention it i do remember them pulling something out of their holsters. Fair enough, sorry :) Guess I was wrong about the grenades explosive force too..
:oops:

Thats a good point about the deployment though. If a modern army were in a woodland setting like Endor, wouldn't they use rifles though?
Being as it is holstered, that suggests the E-11 is something of a cross between the function of a carbine, a sub machine gun, and a machine pistol?
Its too big for a direct comparison with the MP7, but I still hold out that it has the most in common with the MP5-A5, but with the holster perhaps it is made of materials light enough to make this practical?