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Author: Subject: Unconventional Shaped Charges
StevenRS
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[*] posted on 4-1-2008 at 15:04


If I were to hypothetically make my first shaped charge out of a .270 hunting brass, using the copper jacket of a .270 bullet as the liner, and use MEKP as a filler, would it work *at all*? I have a feeling MEKP is too slow, maybe adding it to AN in a 9(AN):1 ratio would work? I was also thinking methyl nitrate might be better, but sadly, I have no concentrated nitric acid, and no way of getting any. I also considered AP for about 1/4 of a second, but it scares me; I don't trust it, and I think it has a lower VoD than MEKP.

I am just looking for some penetration, something to tell me it worked, not anything amazing, that comes later, everyone has to start somewhere.
What kind of penetration should I be looking for for this setup, so I know what to expect?
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[*] posted on 5-1-2008 at 08:37


You can make charges that exhibit the Munroe effect using peroxides (I did it using AP a long time ago). You probably won't get an actual metal jet, but rather a focusing of shockwave and fragments, but if you choose a relatively soft target such as wood, then you'll be able to see the characteristic penetration.
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[*] posted on 5-1-2008 at 20:33


Quote:
Originally posted by StevenRS
sadly, I have no concentrated nitric acid, and no way of getting any.


You are aware that many explosive compounds can be made with concentrated sulfuric acid and nitrate salts rather than sulfuric acid/prepared nitric acid?

[Edited on by Bert]
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StevenRS
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[*] posted on 5-1-2008 at 21:38


I was aware nitric acid could be made that way, but I thought it was not suitable for explosives production without distillation. I really hope I am wrong, can a mixture of nitrates and SA be used straight?
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[*] posted on 5-1-2008 at 21:47


Yes. Search on roguesci.org forum.
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hinz
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[*] posted on 31-1-2008 at 09:38
Results of a 38mm SC


Here is the result of a 38mm shaped charge,it nearly penetrated 72 mm of mild steel(6x12mm mild steel plates welded together).
The HE in the main charge was about 95g 2:1 MHN/NM gel, density about 1,5 g/cm3. Primary was 0,5g Ag2C2*AgNO3/MHN mixture and 2g MHN.
On the bottom you can see the buckle made by the copper jet. On the first picture you can see the aluminium mandrel on which the copper liner was spun. The copper liner had an thickness of about 0,8-1mm(my copper spun liners don’t have an even thickness) and was parabolic formed. I think the copper colored dent was caused by irregularities in the thickness of the liner and thus irregularities in the copper jet.

[Edited on 31-1-2008 by hinz]

[Edited on 1-2-2008 by hinz]

upside wth mandrel.jpg - 34kB
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hinz
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[*] posted on 31-1-2008 at 09:47


Pic 2

Bottom.jpg - 32kB
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nitro-genes
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[*] posted on 1-2-2008 at 05:41


Nice one, 72 mm of steel is a long way! Could you please try to make a better picture of the formed jet channel? Just hold a strong light source next to the camera to make it better visible... :)

What was the appearance of the explosive btw? Did al of the MHN dissolve in the NM or was part of the MHN present as a suspension? From what I remember with PETN, only a small part actually dissolves in the NM, although MHN en PETN are not the same of course. But if so, you could improve the results by incorporating 4% of a binder like NC derived from ping pong balls to get a more homogenous explosive composition and achieve better jet formation...

Looks like your carrot was blown off-center resulting in the copper-coloured dent. This can be the result of many things and I noticed it on several occasions as well.

Were the variations in the liner thickness only present as a gradient going from 1 mm at the top of the cone to 0.8 at the base, or did you measure a difference in liner thickness along the base of the cone? The first doesn't harm jet formation and liners having a gradient in thickness from top to base are used in some SC designs. Don't forget to anneal your liner one final time when your finished spinning to remove stress in the metal that can also affect jet formation.

From what I calculated you used about 1 CD head height, (space between aphex of the cone and the detonator) but how long was the detonator and how was it placed? Sticking the detonator in the explosives composition and to make sure it is completely alligned with the longitudanal axis of the liner is nearly impossible. Therefore I normally only let the base of the detonator touch the explosive composition and don't stick it all the way in.

Nice work, keep it up! :)

[Edited on by nitro-genes]
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[*] posted on 1-2-2008 at 16:49


Here are the close up pictures of the hole, quite difficult to get enough light in it. ;)

You're right, only a small amount of MHN dissolves in the NM actually. I kneaded a bit of the HMN/NM mixture to a piece of coffe filter, so the NM could soak into, and removed it afterwards. As the NM dried, there was only a little bit of MHN left o the paper, visible as a white spot.
I added the NM to the MHN to make it less sentitive, use some of the spare oxygen of MHN and to get the best density out of the HE without pressing it.

The liner thickness variated because the liner was sometimes stopped on the mandrel by the piece of brass and aluminium I uesd to push it onto, so some particles on the mandrel cut into the mandrel as well as into the fresh annealed and soft liner :( (difference in liner thickness along the base of the cone). This caused the round scratches on the mandrel as you can see in the first pictures. Needless to say that these were also cut into the liner, but fotunately not as deep as in the mandrel.

Yes i used about 1 CD head height, but I didn't measure exactly, I made it mostly "by eye" and after I soldered the liner onto the steel pipe, I poured water into the SC on a scale to get its volume and thus the amount of HE I had to prepare. Standoff was about 2,5 CD BTW.
Detonator was made from a 5ml syringe,plased inthe middle of the SC and sticked trough a plexi-glass plate, it had a diameter of about 13mm, it's too small on the picture, but the liner shape should fit quite well.

The carrot was oddly formed, first it made a big 18mm diameter hole, about 20mm deep in the steel and then continued further 40mm with a small diameter of about 8-4 mm from top to bottom, in the end, the copper colored dent was formed, as the dent lacks from impact craters from small particles.

[Edited on 2-2-2008 by hinz]

SC hole.jpg - 45kB
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[*] posted on 6-3-2008 at 00:06


Hinz, how did you make your liner?
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[*] posted on 6-3-2008 at 20:40


Quote:
Originally posted by DNA
Hinz, how did you make your liner?


He said spun Copper on an Aluminum mandrel...
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[*] posted on 10-3-2008 at 07:35


Looks we could all do better if we made better symmetry liners: Your 70mm and my 50mm for 38 and 25mm charges respectively equal only 2 CD, while 5-6 are 'normal' for military charges (which still have to be cost effective, i.e. no tantalum liners with HNIW charge). Special ones go even deeper, what's the record, 10 CD (Axt?)?

One of the reasons I moved on to LSCs. Plus, there's more possible targets for those.
I mean, who needs a 5mm hole in a safe, cash machine, or jeweler's window.... cool:

[Edited on by Boomer]
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[*] posted on 10-3-2008 at 08:47


Up to 9 CD is possible for a simple 60 deg copper cone, having a uniform thickness of 2% CD in combination with octol (350+kbar). Even with cyclotol (300+ kbar) 8 CD is possible, graph is listed in PATR under "Octol". Constraints are most definitely determined by the precision of charge and liner and the allignment for an amateur charge, and greatly determines the maximum streching ability of the jet. Military liner standards call for deviations no greater than serveral micrometers, which is out of reach for spun formed liners as well (without after-machining IMO). My last charge reached 4.2 CD penetration @ 3-4 CD standoff, but liner was spun from 1mm thick copper giving 0.8 mm wallthickness on average. (2.5 % of CD). I've made another liner with a wall thickness of ~0.6mm (1.9% CD) and could possible reach slightly deeper penetration, though 5 CD will be the absolute limit IMO...

Highest numbers I'm aware of were 10-11 CD for molybdenum trumpets and 12 CD using a hemisperical DU liner IIRC...

[Edited on by nitro-genes]

Penetration vs standoff for cyclotol and octol with copper liner.bmp - 40kB
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KemiRockarFett
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[*] posted on 28-3-2008 at 11:24


To increase the energy in the EFP it could be worth to put a mass around the explosive. WATER for instance. A couple of kg water around may be an easy way to increase the efficiency of the device.
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[*] posted on 23-5-2008 at 11:42


Design, analyses & field testing information of a 0.7m shaped charge (apparently the worlds largest - some 440Kg), thought it might be of interest

Attachment: Design.analyses.fieldtestof.70cmshapedcharge.pdf (750kB)
This file has been downloaded 1328 times





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[*] posted on 24-5-2008 at 07:56
NM/TNP- SCs


Becoming aware of the NM Picric acid patent almost makes me wish i hadnt dropped my scale model racing hobbys and disposed of 1/2 gall pure Nm few years back.
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[*] posted on 29-5-2008 at 11:58


Not a unique SC the platter charge or miznay/chardin effect
has me omewhat confused s to the mechanism of te 2 materils commonly used in the platter charge.steel , quite possible a very hard yet ductile steel ad a copper alloy of some sort.The 2 charges utilize different materials in thier shaped concave platters the steel relyin exclusvely on kinetic energy as Ive personally witnessed which can be very effective given the size/wieght of the devices ad the effect of the sc charge inreduing d haping the steel platter to a similar shape/velocity as an armor piercing AT Gun round achievng some 6600 FPS from te shaped warhead.And why does the supposedly iranian designed /manufactured copper platter behave in an almost completely different manner stil relying on kinetic energy but in combination with what appears to be SC heat effect as well?In fcvI believe its the only weapon the Abrams tank crews are really concerned about capable f penetrting the near impenetrable front glacis plate and turett of the Newest Abrams w/the most modern cmpsite armor which easily shrugs off the newest gnerations of RPGs with the capabilitys of penetrating 12-18 in of homogenous steel armor! Not to mention the platter chargess far superior stndoff to normal SC heat weapons?We also began discussg i believe the propogation effect of to small det. tubing?Rather than the 5/16 OD f my presernt tubng or would a
slightly larger tube of say 3/8 od for a composite det of 2 gr.or more HE ?
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[*] posted on 29-5-2008 at 17:20


The answer to why the 'supposed' Iranian designed ATGM's are so effective is spelled 'KORNET' (AT-14/9M133; http://en.wikipedia.org/wiki/AT-14). I strongly suspect that attempting to duplicate the amazing abilities of the 'new Iranian' weapons, will be frustrated by the fact that these weapons are not the ones that are defeating US/Israeli armour packages (you are dealing with the intersection of Iranian propaganda and science here). Unless you access the seriously highly classified Russian database entries for shaped charge weapons, you are unlikely to get useful information on this baby, you certainly won't get it from the Iranian websites.



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[*] posted on 4-6-2008 at 11:13


Quote:
Originally posted by Axt
I can see where your incoherent jet theory is arising from, but most theorys seem to go to shit once you get the the extremes such as a cylinder, I wont speculate as to whats happening. Myuo posted some nice references regarding acceleration of jets through a cylinder, seemingly the effective VOD can be increased by using a hollow cylindrical cavity in its length since the accelerated jet initiates the explosive as it passes through it.

I will probably try greater standoff to define the jet effect. For all I know it may well be accelerated shock waves acting as a hole punch!, which should diminish quickly as standoff is increased.


[Edited on 28-6-2004 by Axt]


From what I understand of construction of a cylindrical shaped charge there should be 0 standoff so your shock wave/hole punch theory may be correct. My only real first hand knowledge is of military origin and the primary purpose of the imp. cylinder SC was to form a large hole of relatively short depth for use against pipelines, engine blocks,bulk petro. tanks etc

[Edited on 4-6-2008 by grndpndr]
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[*] posted on 4-6-2008 at 11:21


I wasn talking about the Iranian ATGMs but the copper platters they are 'allegedly' supplying the insurgents that are then made into platter charges and your very correct any research of the matter of copper versus
steel yields very little info and NO dimensional info although I suppose Pics of the platters themselves an estimate could be made as to dimensions.No doubt the design parameters
of any warhead is a closely guarded secret likely the reason the chinese have a larger spying progrm underway than the russ at the height of the cold war.

I should have qualified the statement the only weapon Abrams tankers fear to the only IED Abrams tankers fear are the platter charges we've discussed and bulk explosive IEDs of several hundred Lbs.

[Edited on 4-6-2008 by grndpndr]

[Edited on 4-6-2008 by grndpndr]
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[*] posted on 6-6-2008 at 22:21


aha, that does make it clearer - they are probably supplying the insurgents in Iraq something similar to that which they are supplying to Hiz'bollox in Lebanon, large EFP type projectiles based upon IED's.

http://www.defense-update.com/newscast/0207/news/010207_efp....

http://www.mnf-iraq.com/index.php?option=com_content&tas...

http://www.mnf-iraq.com/index.php?option=com_content&tas...

http://www.globalsecurity.org/military/systems/munitions/bul...

These aren't overly complex, simply a more advanced 'cheap trick', someone with some knowledge has contributed the original design, but after that even 'desert warriors:D' could acheive a high degree of manufacturing excellence (fucken hell, beat out a shallow copper bowl and mount it backwards).

This picture from Wiki should demonstrate why standoff is essential to the proper utilization of these:

http://en.wikipedia.org/wiki/Explosively_formed_penetrator

Shit happens quick, but it still ain't instantaneous, the penetrator/projectile still needs time and airspace to be explosively forged (the blast / air resistance caves the outer edges back onto the centre - where it forms a fairly well defined slug). Why they don't just setup a small machine shop (there are lathes & mills in Iraq, surely) and machine out or cast & then polish a copper cone and get the improved penetration is probably beyond argument, given the size of the charges they are using, they don't fucking need to.




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grndpndr
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[*] posted on 12-6-2008 at 11:34


I was priveledged to fire many LAWs at M113 APCs what suprised me the most now thinking back on it was how far a coherent jet stayed formed. The M113 as you may know is armored in relatively thin AL armor.Still the 66mm warhead of the LAW (advertised as capable of pen.12 in homogenous AP) penetrated both sides of the vehicle so It penetrated about an inch of hardened AL and then retained the coherehecy of the jet for another 4-5 ft penetrating the other side although with a diminished hole size.Yet we see these same vehicles with cage type predetonation protection from RPGs a much more powerful warhead near double the penetratin capability?My apologys if this has
become more of a military question in nature but perhaps
the fact of the coherency of the LAW s jet and I assume
other military heat warheads wll raise questions besides
simple penetration depth of a single target plate.Perhps space 2 test plates several ft apart?

PS;As far as size and improvised patter charges I would say
yes virtually any garage with few simple metalwrking tools
and access to a metals scrap heap has access to the makings of a crude but effective paltter charge,even a manhole cover backd with adequate explosive would cause catastrophic damage to a Light armored vehicle and possibly immobilize an abrams.Given the proper design parameters of an engineered device and slightly more sophisticated machine shop a clever machinist could likely urn out quite capable platters. i have a photograph of a captured imp device utilizing one of the copper platters supplied by iran
but w/o anything to compare its size to It simply appears to be a copper bowl inside perhaps 10+ in steel tubing.

[Edited on 12-6-2008 by grndpndr]

[Edited on 12-6-2008 by grndpndr]
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LSD25
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[*] posted on 13-6-2008 at 07:47


Yeah, I know the terminology and I also know the equipment (in an almost biblical sense indeed). I used to drop 3 and a bit Kg bombs down tubes mounted in a turntable in the back of M113 variants. I have also utilized charlie guts-aches against immobilized cars which had been dumped on a range.

Yeah, by the look of the charges they could be beaten out by anyone with even rudimentary equipment (ball peen hammer and something to bash it out against). By the look of them the rest of the casing is only rudimentary, it doesn't have to be all that strong - the platter is only barely held in place so it would direct the force of the explosion extremely well away from the casing material. Even an steel pot should be sufficient, by the time it deforms the platter is well on its way.

As it is more a kinetic penetrator than a jet, the use of massive explosive charges would see the formation of fucking huge-mass, massive kinetic energy, penetrators which explains why they have succesfully been used against both Abrams & Merkavas (even the MkIV apparently, though the crew generally survive, not so with the MkII/III & the Mk.I chassis Namer APC).

BTW, see the Dove-ish contender who is touted to stand against Netanyahu saying that Iran will dissapear long before Israel? Wonder what is going to happen in Iraq & Afghanistan when both the yanks and Israel start on Iran? My tip is that we'll find out inside 12 months.




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[*] posted on 13-6-2008 at 08:40


It would likely take a talented professonal copper smith and hardwood etc form to hammer a platter to relatively close tolerances but im sure it could be done with frequent reheating to resoften the copper alloy t prevent cracking .but with the vast investment in machinery and Im sure very costly manpower lol if even a small percentage f these were successfully detonated destroying/damaging $250,ooo humvees/damaging couple million dollar tanks/injuring-killing troopers a far more expensive bill, that would be cost effective.Or as i suggested earlier steel manhole covers and build 100lb platter charges also effective in a bind.



[Edited on 17-6-2008 by The_Davster]
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[*] posted on 15-6-2008 at 04:26


As to the complexity of the weapons, look at this before you dismiss them out of hand as being beyond the capacity of this mob: http://www.armscollectors.com/darra/darra.htm The original article was written in the early '60's but I'd reckon this mob are fucking busy right now, wouldn't you?


The political shit left allover this thread has been removed.
-Davster


[Edited on 17-6-2008 by The_Davster]

[Edited on 17-6-2008 by The_Davster]




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