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US Army Fielding XM-25 In Afghanistan

Finally! Some journalistic realism! /pedantry off

Being sensible and everything but,

Surely that is.... in fact a very small wall to hide behind.

With a bit of patience and a steady hand you would get the dude without resort to a multi million dollar weapon.

What's the old story

NASA spent millions developing a pen that could work upside down, underwater, in a vacuum and in zero gravity (Fisher Space Pen)

The russians took a pencil

PoGs
pocketcomms.com
 
What's the old story

NASA spent millions developing a pen that could work upside down, underwater, in a vacuum and in zero gravity (Fisher Space Pen)

The russians took a pencil

Ahem, urban legend. The last thing that you want floating around in space around all those electrical circuits is small broken pieces of a conductive material that you cannot even attract with a magnet.

But I understand your point.
 
Being sensible and everything but,

Surely that is.... in fact a very small wall to hide behind.

With a bit of patience and a steady hand you would get the dude without resort to a multi million dollar weapon.

What's the old story

NASA spent millions developing a pen that could work upside down, underwater, in a vacuum and in zero gravity (Fisher Space Pen)

The russians took a pencil

PoGs
pocketcomms.com

Of course, it may be entirely possible that the wall in the diagram is for illustration only?


Besides, how much patience and a steady hands will you have when:

1) You target decides not to obligingly show his head, and scuttle off under cover to find another place to shoot at you from
2) His mates are shooting at you from another fire position, which no-one is able to identify yet
3) One of your mates is laying on the ground with half his leg missing, after stepping on the IED that triggered the ambush


Anything that helps us whallop the bad guy quickly, causing minimum collateral damage and without need to call up armoured/aviation support has got to be a good thing, no?
 
What I'm trying to tell you is that, theory aside, trying to get UHMWPE to burn as a result of a transient heating effect is very difficult in practice, even when the impacting projectile is supposedly pyrophoric.

Yes, I understand what you're getting at. But UHMWPE is a fuel under the right circumstances. A 2x2x2mm burning magnesium chip may not set the whole vest alight but it will certainly burn through.

I'm looking at it this way: UHMWPE is chemically similar to paraffin wax except that is has longer molecular chains and is highly aligned. Even warmed up liquid paraffin wax can quench a burning match if you plunge it into it (your point), but if you have an intense heat source capable of burning in the absence of air + bits of detritus that act like wicks (not inconceivable, considering all the clothing and soot around) then you can get sustained burning (my point).

Also one interesting thing I observed when heating woven Dyneema, as I have done in practice (during my PhD), was that above a certain temperature, the flat fabrics bunch up into a mass of coiled fibres. I found this out when a Masters student I was supervising was trying to impregnate and cure woven Dyneema within an epoxy matrix on a hot plate. I find the Youtube video released by DSM on the flammability test of Spectra fibres as highly unconvincing. Anyone with that sort of fire on their body, even if armoured, would have severe burns to the head, neck, chin and scalp after being on fire for 30 seconds.

Of course, it may be entirely possible that the wall in the diagram is for illustration only?


Besides, how much patience and a steady hands will you have when:

1) You target decides not to obligingly show his head, and scuttle off under cover to find another place to shoot at you from
2) His mates are shooting at you from another fire position, which no-one is able to identify yet
3) One of your mates is laying on the ground with half his leg missing, after stepping on the IED that triggered the ambush


Anything that helps us whallop the bad guy quickly, causing minimum collateral damage and without need to call up armoured/aviation support has got to be a good thing, no?

Would our Armed Forces consider a weapon that selectively targets anyone carrying a large hunk of metal in a specified area as indiscriminate? Because otherwise I won't even bother submitting it as a research proposal...
 
Of course, it may be entirely possible that the wall in the diagram is for illustration only?


Besides, how much patience and a steady hands will you have when:

1) You target decides not to obligingly show his head, and scuttle off under cover to find another place to shoot at you from
2) His mates are shooting at you from another fire position, which no-one is able to identify yet
3) One of your mates is laying on the ground with half his leg missing, after stepping on the IED that triggered the ambush


Anything that helps us whallop the bad guy quickly, causing minimum collateral damage and without need to call up armoured/aviation support has got to be a good thing, no?

I have had a steady hand and sadly been in pretty much most of the senarios you mention.

I think you may be taking this a little too seriously.........you don't work for the manufacturer by any chance :)

PoGs
pocketcomms.com
 
Yes, I understand what you're getting at. But UHMWPE is a fuel under the right circumstances. A 2x2x2mm burning magnesium chip may not set the whole vest alight but it will certainly burn through.

Are you talking about a high velocity fragment burning its way through as part of the penetration process, or simply a fragment which settles and burns? Either way your 2mm fragment is also going to burn up very quickly.

I'm looking at it this way: UHMWPE is chemically similar to paraffin wax except that is has longer molecular chains and is highly aligned. Even warmed up liquid paraffin wax can quench a burning match if you plunge it into it (your point), but if you have an intense heat source capable of burning in the absence of air + bits of detritus that act like wicks (not inconceivable, considering all the clothing and soot around) then you can get sustained burning (my point).

No, my point was that you need considerable ammount of energy, heat capacity and time to melt and ignite the material enough to get a sustained flame, which I suspect is much more than your small magnesium flakes could induce.

Also one interesting thing I observed when heating woven Dyneema, as I have done in practice (during my PhD), was that above a certain temperature, the flat fabrics bunch up into a mass of coiled fibres. I found this out when a Masters student I was supervising was trying to impregnate and cure woven Dyneema within an epoxy matrix on a hot plate. I find the Youtube video released by DSM on the flammability test of Spectra fibres as highly unconvincing. Anyone with that sort of fire on their body, even if armoured, would have severe burns to the head, neck, chin and scalp after being on fire for 30 seconds.

I've not seen that video, but I have seen testing done by MoD on many UHMWPE products to convince me that fire is just not an issue when confronted with the majority of likely threats that would not otherwise result in the wearer expiring unpleasantly anyway, and the ballistic efficiency of these materials far outweighs the minor risk.

At the end of the day though, most people do do not wear large areas of exposed UHMWPE on their protective equipment enough to warrant this as justification to exploit such a mechanism. And there is still the issue that designing weapons to deliberately cause incapacitation or death by burning is strictly a no-no...



Would our Armed Forces consider a weapon that selectively targets anyone carrying a large hunk of metal in a specified area as indiscriminate? Because otherwise I won't even bother submitting it as a research proposal...

I would say they most certainly would.


If you want someone to bite your arm off for a research proposal, try coming up with something that will detect a buried explosive charge with minimal metal content ahead of a vehicle driving at a realistic (say 30-40mph) speed.
 
Of course, it may be entirely possible that the wall in the diagram is for illustration only?

Yup - walls are a bonus. This thing was also designed as a solution to the problem of "how do you get soldiers to point the weapon accurately enough at the enemy, when the enemy is 600m away". Assuming the target is the same size, it's either "train all of your soldiers to ninja status on L85" or "give them a BFO gravelbelly rifle".

The XM25 designers chose another route - i.e. "make the target big enough that the average bloke can hit it at 800m". With a bullet, "good enough" is "point exactly at the target"; with a fragmentation round, it's "the target, and a four-foot circle around them". The trick is making the fragmentation round go boom at the right moment.

So, it's not just "bloke hiding behind wall" or "bloke in a shellscrape", it's also "bloke in open 800m away, assuming you can point the laser spot at something at the correct range".
 
Yup - walls are a bonus. This thing was also designed as a solution to the problem of "how do you get soldiers to point the weapon accurately enough at the enemy, when the enemy is 600m away". Assuming the target is the same size, it's either "train all of your soldiers to ninja status on L85" or "give them a BFO gravelbelly rifle".

The XM25 designers chose another route - i.e. "make the target big enough that the average bloke can hit it at 800m". With a bullet, "good enough" is "point exactly at the target"; with a fragmentation round, it's "the target, and a four-foot circle around them". The trick is making the fragmentation round go boom at the right moment.

So, it's not just "bloke hiding behind wall" or "bloke in a shellscrape", it's also "bloke in open 800m away, assuming you can point the laser spot at something at the correct range".

It will never catch on in the UK as the ranges at Bisley could never be templated successfully for it...

.... unless, of course, you make the butt party the target
 
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