Military History | How To Make War | Wars Around the World Rules of Use How to Behave on an Internet Forum
Armor Discussion Board
   Return to Topic Page
Subject: Iraq Loads Up On 120mm
SYSOP    11/20/2014 5:58:02 AM
 
Quote    Reply

Show Only Poster Name and Title     Newest to Oldest
Pages: 1 2
Blacktail       11/20/2014 7:49:06 AM
You have to love the irony that even a puppet state of the US government will use basic HE rounds in their tank guns, but the US military still fiercely resists their acquisition. This, despite a full decade of counter-insurgency conflict, in which similar rounds in the inventories of US allies had proven indispensable in combat;
 
Quote    Reply

Shirrush       11/20/2014 3:16:34 PM
That's not too many rounds, a bit less than 10 full bellies per tank. What do they need the KE arrow rounds for? Da'esh has tanks? Or do they plan to help their Iranian correligionnaries fight against "whomever"?
 
Quote    Reply

JFKY    I think this article is wrong   11/20/2014 3:33:17 PM

As far as I can tell, there is NO “M-83” 120mm M-1
round.  There IS an M-830 120 mm round
for the M-1.  It isn’t a Hi Explosive
round, it is a HEAT-M(ulti)-P(urpose) round. 
If it’s the M-830a1 version it is a Programmable Air Burst Munition.

So, Blacktail the US actually has adopted a round at least
akin to the HE round….I would say it has been 40-plus years since the US
fielded, & needed to fielded an HE round. The US Army had a HEP round, for
the 105mm M-68, which could be used against personnel or structures, but was
still primarily an AT round.

Anyway, I believe that the author means that the Iraqi’s are
purchasing the M-830 MP round, not the “M-83” HE round.

 

 



 
Quote    Reply

keffler25       11/20/2014 6:20:48 PM
Beat me to it.
 
Quote    Reply

paperpusher       11/20/2014 8:31:17 PM
I guess ISIL is running low.
 
Quote    Reply

Blacktail       11/24/2014 4:34:47 AM

"There IS an M-830 120 mm round for the M-1.  It isn’t a Hi Explosive round, it is a HEAT-M(ulti)-P(urpose) round. If it’s the M-830a1 version it is a Programmable Air Burst Munition."
The M830A1 round --- euphemistically re-designated as "MPAT" and "HEAT-MP" at different times --- is only a HEAT round with a fragmentation casing, regardless of how it is fused. In fact, the projectile is the same used in the M456A2 105mm HEAT round, but with a sabot wrapped around it so the projectile can be fired from a 120mm gun.

HEAT also doesn't work against structures. This is the hole a HEAT warhead makes when it hits a structure --- you couldn't fit more than three fingers into it;
http://www.pahte.com/images/05.02.11_Liberia._Lofa._Zorzor._An_RPG_and_a_wall.jpg

This is what happens inside a structure hit by a HEAT round;
http://www.globalsecurity.org/military/library/policy/army/fm/3-06-11/image1370.gif

This is the hole a HEP/HESH warhead makes when it hits a structure. The effect of HE is similar;
http://www.foreignpolicy.com/files/fp_uploaded_images/110408_HESH_AJDABIA%20%284%29.jpg

What happens inside a structure hit by a HEP/HESH round is pretty obvious.

We also know for a fact that the M830A1 HEAT round is competely useless against personnel, because it's already been tried;
http://ciar.org/ttk/mbt/armor/armor-magazine/armor-mag.2004.ma/2orr04.pdf

This video demonstrates what an HE-FRAG round does to both structures and personnel;
https://www.youtube.com/watch?v=iI6HeMMkZEk

This demonstrates the effects of the M329 APAM round, which the US military has also paid only lip-service to;
https://www.youtube.com/watch?v=YjAY9EgjqTA


"So, Blacktail the US actually has adopted a round at least akin to the HE round….I would say it has been 40-plus years since the US fielded, & needed to fielded an HE round."
The article I posted previously makes it pretty clear that there's a need for an HE round.

Moreover, HEAT rounds aren't akin to HE rounds at all, because they emply *shaped charges* that concentrate most of the blast force into the charge liner, which when projected is deformed into becomes a penetrator. Against personnel and structured, a HEAT round is a very expensive process duplication of a single 30mm AP round.

Even if the above issue weren't so, HEAT rounds inevitably have smaller fillers than HE or HESH rounds. That means a smaller blast radius and shrapnel radius.

It's no accident that every large-bore gun ever fielded by every Eastern Bloc country fires HE and/or HE-FRAG rounds --- or that the standard Soviet Army load-out for a T-72 was always 20 HE-FRAG, 15 HEAT, and 5 APFSDS rounds. This is still true to this day of the Russian Army, and most other former Eastern Bloc nations. And they know a thing or two about fighting personnel and structures using tanks;
http://www.lonesentry.com/articles/sovtanks/

http://www.lonesentry.com/articles/ttt07/stalingrad.html

"The US Army had a HEP round, for the 105mm M-68, which could be used against personnel or structures, but was still primarily an AT round."
If that were true, the M456 105mm HEAT round would never have been fielded for use in the M68. It was.

"Anyway, I believe that the author means that the Iraqi’s are purchasing the M-830 MP round, not the “M-83” HE round."
If they don't field the correct ammunition for fighting an insurgency, they won't win. For the US military, not winning means coming home, and saying you won anyway. Losing to ISIS on your own soil means instant death.
 
Quote    Reply

keffler25       11/24/2014 10:06:33 AM
!@#$%^&*()!@!
 
You MIGHT want to be a little less DECEPTIVE, BT in your examples.
 
Case in point:
 
How is a ROCKET PROPELLED GRENADE (RPG-7) with a HEAT warhead equal in velocity, fusing, explosive charge and penetrative cavity production to the M456A2 again?   
 
DO MUCH BETTER!
 
Quote    Reply

Blacktail    keffler25   11/24/2014 7:56:29 PM

 
But now that you mention it, the M456A2 and M830A1 have a filler of  2.14lbs of Composition B (equal to 3.68lbs of TNT), compared to 1.6lbs of HMX (equal to 2.77lbs of TNT). You can split hairs over that all you want, but it's not a big difference in force, and it's still irrelevant in light of how shaped charges function. Meanwhile, a 105mm M393A1 HEP round contains 6.1lbs of Composition A (equal to 10lbs of TNT), while a 120mm L31 HESH round contains 8.8lbs of filler, equal to at least 14lbs of TNT. The Slsgr 95 HE round (which was demonstrated in one of the videos I posted above --- and which the US Army's "leadership" is stonewalling acquisition of by the US military) has a 5.95lb filler that has to be equal to at least 9.5lbs of TNT.
 
Even the M71A1 HE --- a mere 90mm round, once used in the M48A3 Patton --- has more anti-personnel, anti-material, and anti-structure capability than an M830A1, with 2.15lbs of unshaped Composition B. When your arsenal doesn't even have a 120mm shell that can complete with a 90mm shell against more than 95% of all targets a tank could ever possibly face in any possible war, you've screwed-up *badly*.
 
Quote    Reply

keffler25       11/24/2014 11:43:04 PM
Kinetic impact of a large diameter artillery shell with a tandem charge effect versus a low velocity small diameter primitive single charge shaped explosive rocket. (Why no data on the RPG-7 fill? [Roughly about 2-2.5 kgs equivalent TNT yield)
 
Your supplied fill numbers are wrong by the way as to yields. 
 
Yeah, you basically screwed up, BT. You obviously DON'T know what you are talking about.  
 
 
Quote    Reply

Blacktail       11/28/2014 11:47:37 PM
"Why no data on the RPG-7 fill?"
The first several paragraphs was eaten by the comment system, along with the data in them.


"Kinetic impact of a large diameter artillery shell with a tandem charge effect versus a low velocity small diameter primitive single charge shaped explosive rocket."
This is a Red Herring Fallacy, and an attempt at Moving the Goalpost as well.

The destructive mechanism of a shaped charge projectile is the blast yield of the warhead alone. That's why they're referred to as CE ("Chemical Energy") projectiles, rather than KE ("Kinetic Energy") projectiles. A shaped charge munition explodes at or immediately before the moment of contact with the target, or the successful formation and application of the penetrator from the charge liner does not occur. Moreover, the penetrator itself is fired by the charge in velocities many times that of the projectile itself.

As such, the kinetic energy of a projectile with a shaped charge warhead is completely meaningless.


"Your supplied fill numbers are wrong by the way as to yields."
On the contrary, all of my data is correct.

According to the US Army's official data the M456A2/M830A1 contains 2.14lbs of Composition B; the 105mm M393A1 HEP round contains 6.1lbs of Composition A; and the 90mm M70A1 HE round contains 2.15lbs of unshaped Composition B
https://archive.org/stream/milmanual-tm-43-0001-28-army-data-sheets---guns-howizers-mortars-rifle/tm-43-0001-28_army_data_sheets_-_guns_howizers_mortars_rifles_gren_launchers__arty_fuzes_djvu.txt

According to ORDATA, the PG-7VL rocket contains 730g (1.6lbs) of HMX;
http://en.wikipedia.org/wiki/RPG-7#Specifications

The TNT equivalence of Compositions A and B are listed here;
http://en.wikipedia.org/wiki/Relative_effectiveness_factor

The TNT equivalence of HMX is listed here
http://en.wikipedia.org/wiki/HMX

The yields of 1lb of these explosives is equal to this much TNT;
Composition A: 1.65lbs
Composition B: 1.72lbs
HMX: 1.7lbs

From this information, it's easy to calculate the blast yield of these munitions;
PG-7VL HEAT: 1.6lbs x 1.7 = 2.72lbs of TNT
M456A2 HEAT: 2.14lbs x 1.72 = 3.68lbs of TNT
M830A1 HEAT: 2.14lbs x 1.72 = 3.68lbs of TNT
M393A1 HEP: 6.1lbs x 1.65 = 10lbs of TNT
M71A1 HE: 2.15lbs x 1.72 = 3.69lbs of TNT

M456A2/M830A1 is 73% more powerful; but in context with the fact that we're only talking about the equivalent to 2.7lbs to 3.7lbs of TNT, it's a pretty hollow "advantage".

Plus, the fact that HEP has an unshaped filler makes it exponentially more destructive against personnel and material targets than HEAT, even if it had exactly the same TNT equivalent blast yield --- and it's clear that M393A1 HEP has almost three time as much "boom" as any of the other three rounds. Moreover, despite being 15mm smaller in bore, the M71A1 packs almost exactly the same explosive yield as the M456A2 and M830A1, but it's *still* much more effective against personnel, structures, helicopters, aircraft, fortifications, and softskin vehicles, as the M71A1 is unshaped.
And that's another thing. Enemy tanks are an extreme rarity in tank warfare in the wars where they exist --- and in most, they don't. That's why the US military's tank ammunition priorities are completely wrong.
 
 
"Yeah, you basically screwed up, BT. You obviously DON'T know what you are talking about."
The fact that I provided sources and data makes it pretty clear that I know what I'm talking about. You didn't, and it's too late for a comeback.
 
Quote    Reply
1 2



 Latest
 News
 
 Most
 Read
 
 Most
 Commented
 Hot
 Topics