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Which Is The Weight Of The High Explosive Content Of Modern 40 Mm Rounds?


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#1 ramontxo

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Posted 23 February 2013 - 1258 PM

Modern light to medium AFVs tend to be armed with automatic weapons up to this caliber (40mm). Though modern electronics can do miracles, (like assuring high speed rounds with a level trayectory to go off above ground exactly when needed ), will a short (six to ten rounds) burst carry enough hitting power against fortified positions?. I am thinking of operations under an urban warfare context, with enemy troops concealed in fortifed houses and the like... As always thanks a lot in advance to the far more learned...

#2 rohala

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Posted 23 February 2013 - 1415 PM

enough hitting power against fortified positions

How do you mean that?

I have wondered the same question myself, namely how effective against dug-in personnel really are the 25mm-30mm guns found on IFVs. My thought is that their explosive content is meager and unless they are extremely accurate their effectiveness at long ranges (eg 1000 meters) must be pretty low.
I think a HE 40mm round for the Bofors gun has an explosive content of around 90-100gr, which is substantial, comparable to a powerful hand grenade. I woundnt' trust it to damage a briack and concrete building such as the ones found here and in Syria, but if it hits through a window it can probably take out the men inside the room.

In the Syria thread someone posted a long video of combat footage from Daraya. There at some point you can see a BMP-2 shooting single rounds at what I understood were different spots. I assume it was putting one round in every window, probably preemptively.

#3 EchoFiveMike

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Posted 23 February 2013 - 1722 PM

The new CTA 40mm HE, which has a round nose, high volume form, has a NEW of around 115g. Which, as you say, makes it about like a good handgrenade. The only stipulation is that it must have a good fragmentation design, as that is what creates casualties, not HE. S/F....Ken M

#4 Jason L

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Posted 23 February 2013 - 1737 PM

I have wondered the same question myself, namely how effective against dug-in personnel really are the 25mm-30mm guns found on IFVs. My thought is that their explosive content is meager and unless they are extremely accurate their effectiveness at long ranges (eg 1000 meters) must be pretty low.
I think a HE 40mm round for the Bofors gun has an explosive content of around 90-100gr, which is substantial, comparable to a powerful hand grenade. I woundnt' trust it to damage a briack and concrete building such as the ones found here and in Syria, but if it hits through a window it can probably take out the men inside the room.

In the Syria thread someone posted a long video of combat footage from Daraya. There at some point you can see a BMP-2 shooting single rounds at what I understood were different spots. I assume it was putting one round in every window, probably preemptively.


White papers on the modern 30 mm and 40 mm stuff with smart and ranged fuzing promises to be pretty damn deadly against infantry. At least based on the tests versus silhouettes and mannequins in various conditions of partial cover.

It's really not the fill that matters so much as the fragmentation performance.

Dealing with serious fortifications naturally requires a larger bore gun with some sort of penetrating capability and a warhead with either naturally fragmenting design (PELE) or clever fusing.

Edited by Jason L, 23 February 2013 - 1740 PM.


#5 Max H

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Posted 23 February 2013 - 1750 PM

I woundnt' trust it to damage a briack and concrete building such as the ones found here and in Syria,


I disagree, going by this image on tony william's grate site:
Posted Image

The maturity briefing claims it can defeat 210mm of metal reinforced concrete in PD mode.

#6 Jason L

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Posted 23 February 2013 - 1803 PM


I woundnt' trust it to damage a briack and concrete building such as the ones found here and in Syria,


I disagree, going by this image on tony william's grate site:
Posted Image

The maturity briefing claims it can defeat 210mm of metal reinforced concrete in PD mode.


20 mm Tungsten PELE rounds will do about 200 mm into rebared concrete.

Edited by Jason L, 23 February 2013 - 1803 PM.


#7 EchoFiveMike

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Posted 23 February 2013 - 2005 PM

OK, so it breaks a little hole into concrete, that's nice when we start fighting in Detroit.

What does it do in 500+mm adobe(or other 3rd world construction) and can it make a breach into concrete without using the entire basic load? These are more valid criteria.
S/F.....Ken M

#8 Jason L

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Posted 23 February 2013 - 2041 PM

Certainly for PELE-type rounds, which rely on hydrodynamic deformation and not explosives, if the round actually succeeds in breaching the wall it preserves a lot of is fragmentation ability.

Likewise all these newer multipurpose rounds try to breach prior to fusing the actual warhead.

The actual limits aren't obviously published but the rounds are overall pretty competent. Clearly they can't service every single battlefield fortification, but that's what the IFVs missile system and tanks/gun systems are for.

#9 Max H

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Posted 23 February 2013 - 2047 PM

That thick? :blink: I stand corrected.

#10 Tony Williams

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Posted 24 February 2013 - 0634 AM

According to my data, the experimental ATK 40x180 "Super 40" HEAB projectile contains 70g, the 40CTA 120g, and the 40mm Bofors L70 100-165g depending on the type.

#11 DougRichards

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Posted 24 February 2013 - 0639 AM

Years ago the HE content of the HE round for the British 2pdr (ie 40mm) round was described as being about the same as an hand grenade.

Not much has changed.

Given that was a very similar shell to that used in the 40mm pom-pom: no not eggs-zachary the same (and nothing to do with lesbian cheerleaders and their pom-pons... ) it was considered that a shell from the 40mm pom pom could down most single and twin engine aircraft, it only took about the same effect as a hand grenade aganst those targets to have a decent effect.

#12 ramontxo

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Posted 24 February 2013 - 1058 AM

According to my data, the experimental ATK 40x180 "Super 40" HEAB projectile contains 70g, the 40CTA 120g, and the 40mm Bofors L70 100-165g depending on the type.

First thanks very much to everybody, 6 rounds with 165g each, means about one kilogram of modern high explosive, add the kinetic energy of the incoming rounds and it can probably take care of any enemy held position..

Edited by ramontxo, 24 February 2013 - 1059 AM.


#13 Jason L

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Posted 24 February 2013 - 1059 AM

Well, the density of HE compositions hasn't really changed much since WW2, nor has the casing material, so the only path to fitting in more HE is fuze miniaturization. Not really surprising autocannon rounds haven't changed much in that regards since their inception.

#14 Max H

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Posted 24 February 2013 - 1107 AM

the 40CTA 120g,


I believe you're slightly mistaken on that - E5M's figure of 115g agrees with the brochure

#15 EchoFiveMike

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Posted 24 February 2013 - 1846 PM

First thanks very much to everybody, 6 rounds with 165g each, means about one kilogram of modern high explosive, add the kinetic energy of the incoming rounds and it can probably take care of any enemy held position..


That's really going to depend upon the enemy positions, isn't it? If the enemy is properly spaced, 6 rds may only kill 6 troops, at best. S/F.....Ken M

#16 Simon Tan

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Posted 24 February 2013 - 1924 PM

Historically, light autocannon are used to pick through concrete and masonry structures, creating a pathway into the target. See Shilka, Vulcan, Sergei, Vierling, et al. Once the breach is made, then it's just a matter of filling it with yet more fire. Heavy stone and thick adobe structures can be a bit of a pain in this regard so you work on portals and openings. Firing loops are a good starting point barring windows and doors.
Hosing an apartment block in Homs and trying to get some results against troops in rubbled Benedectine monastries is two aspects of your question.

#17 TTK Ciar

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Posted 24 February 2013 - 2034 PM

According to this paper, even very good adobe has only 6%-8% the tensile strength of *unreinforced* concrete:

http://ciar.org/ttk/...lmeida.2011.pdf

I know the resistance of materials to various threats is more complex than any single metric (like tensile strength), but I would expect having such a low strength in tension would cause it to fell apart a lot more readily than reinforced concrete.

Does anyone know from first-hand experience whether half a meter of adobe wall offers much more or less resistance to fire than much thinner brick or concrete walls? Or have a paper which describes the results of testing?

#18 EchoFiveMike

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Posted 24 February 2013 - 2107 PM

I know that adobe in Iraq stopped 50cal API and SLAP like a sponge, as well as 40mm HEDP, both M203 and Mk19. Never hit one with SMAW or AT4, but that might be enough.

A breach needs to be large enough to get troops into it, getting stuck in the street is unacceptable.

You normally would just use a satchel charge, but that uses up explosives quick, fast and in a hurry. S/F.....Ken M

#19 Tony Williams

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Posted 24 February 2013 - 2238 PM


the 40CTA 120g,


I believe you're slightly mistaken on that - E5M's figure of 115g agrees with the brochure


That's an old brochure - still refers to the Warrior replacement turret (that contract was lost years ago) and the French unmanned one (which seems to have been dropped). The 2010/11 edition of Jane's Ammunition Handbook quotes 115g, but in current editions the data table has been amended to show 120g.

#20 rmgill

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Posted 24 February 2013 - 2349 PM

I know that adobe in Iraq stopped 50cal API and SLAP like a sponge, as well as 40mm HEDP, both M203 and Mk19. Never hit one with SMAW or AT4, but that might be enough.

A breach needs to be large enough to get troops into it, getting stuck in the street is unacceptable.

You normally would just use a satchel charge, but that uses up explosives quick, fast and in a hurry. S/F.....Ken M


If you want mouseholes for troops to get through you need a good sized AT weapon for that. Piats were used for this in Europe in the street fighting. Advantage with the PIAT in this being no backblast so you could do it from inside one building, presumably to get into the next, assuming a 'little bit' of stand off for the gunner I guess.




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