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Posted: 1/22/2006 2:15:25 PM EDT
Once upon a time on a FTX, I grabbed a nearby umpire and told him I was going to put some 40mm rounds on an OPFOR M113 about 300 yards out. He gave me corrections, made me shoot it with both the quadrant and leaf sights, and finally told me I was putting the rounds on target. "Effect?" I asked. "hmm...can you take out a M113 with a 203?", he mused, and then wandered away.

Well? What would happen, assuming HE rounds?
Link Posted: 1/22/2006 2:20:46 PM EDT
Id say a bumpy ride for those inside...M113s are pretty haas
Link Posted: 1/22/2006 2:21:40 PM EDT
I'll hold your beer.
Link Posted: 1/22/2006 2:22:36 PM EDT
if you landed some rounds on top you might be able to poke some holes in it with HEDP rounds. if it were buttoned up you could probably screw the crew up pretty good with the overpressure assuming you penetrate
Link Posted: 1/22/2006 2:24:01 PM EDT
Perfect hit in just the right place on a track with an HE round or through an open hatch and yes, it can take out a 113. However, a 40mm round of any type will not pierce the armor on a 113.
Link Posted: 1/22/2006 2:24:34 PM EDT
I'd think HEDP would put a hurtin' on it, especially if fired at a right angle close up.
Link Posted: 1/22/2006 2:31:34 PM EDT
I'll go find out

(Operation Flashpoint)
Link Posted: 1/22/2006 2:34:03 PM EDT
If it was a original unmodified M113 you could put a hole in it but you would be unlikely to kill anyone inside. If you got into the engine bay you might cut a fuel or oil line and get a mobility kill.

This is all the damage a much bigger 57mm RCL round did to a mostly original M113 in Vietnam.


Once the gasoline engines were replaced with diesels, the M113 was pretty safe from VC/NVA direct fire weapons.

Link Posted: 1/22/2006 2:34:27 PM EDT

Originally Posted By PsyWarrior:
Perfect hit in just the right place on a track with an HE round or through an open hatch and yes, it can take out a 113. However, a 40mm round of any type will not pierce the armor on a 113.



A HEDP will cut a hole in it like a hot knife through butter. Shaped-charges have no problem penetrating a M113.

You should see what a Maverick does, little shaped-charge holes my ass.
Link Posted: 1/22/2006 2:35:53 PM EDT
[Last Edit: 1/22/2006 2:38:09 PM EDT by Warrior-Poet]
Yes.


M433 40mm Cartridge High-explosive dual purpose (HEDP)
High-explosive dual purpose (HEDP) round. This round has an olive drab aluminum skirt with a steel cup attached, white markings, and a gold ogive; it penetrates at least 5 cm (2 inches) when fired straight at steel armor. It arms between 14 and 27 meters, and it causes casualties within a 5-meter radius



Notice the copper liner: HEAT/Munroe effect




The M113 does not have 5cm armor.

For the MK19:

M430 HEDP (high-explosive, dual-purpose)
The HEDP (high-explosive, dual-purpose) M430 cartridge, joined with M16A2 links, is the standard round for the MK 19. The impact-type round penetrates 2 inches (same 5cm) of steel armor at 0-degree obliquity and inflicts personnel casualties in the target area. This round is packed in an M548 ammunition container (48 rounds, linked, in each container). It is olive drab with a yellow ogive and yellow markings. It has a PIBD, M549 fuze, and Comp B filler. It arms between 18 to 30 meters and has a casualty radius of 15 meters.

Identification-Olive drab with yellow-olive and yellow markings.
Fuze-Point initiating, base detonating (PIBD) M549.
Filler-Composition B.
Arming distance-18 to 30 meters.
Kill radius-Approximately 5 meters.
Maximum range-2,200 meters.
Wound radius-Approximately 15 meters.
Maximum effective range-1,500 meters.


Link Posted: 1/22/2006 2:38:37 PM EDT

Originally Posted By eodtech2000:

Originally Posted By PsyWarrior:
Perfect hit in just the right place on a track with an HE round or through an open hatch and yes, it can take out a 113. However, a 40mm round of any type will not pierce the armor on a 113.



A HEDP will cut a hole in it like a hot knife through butter. Shaped-charges have no problem penetrating a M113.

You should see what a Maverick does, little shaped-charge holes my ass.



It will go through but like a hot knife through butter is a bit much. It wont make much of a hole.

The grenades are rated for 50mm at 0deg The M113 is 38mm thick. Even the 57mm HEAT that made the hole in that picture I posted above was rated at 80mm penetration, and look at all the bigger hole it made. Where its located it probably went into the engine and disabled it but its unlikely it killed anyone.
Link Posted: 1/22/2006 2:39:06 PM EDT
Took 5 rounds.
Link Posted: 1/22/2006 2:40:23 PM EDT

Originally Posted By raven:
Took 5 rounds.



Wow that few? Did you get a engine kill or start some sort of fire?
Link Posted: 1/22/2006 2:41:36 PM EDT

Originally Posted By ArmdLbrl:

Originally Posted By raven:
Took 5 rounds.



Wow that few? Did you get a engine kill or start some sort of fire?



This is in a PC game. The driver jumped out and the thing started smoking after 5 hits.
Link Posted: 1/22/2006 2:42:15 PM EDT
OK, I stand corrected, but will explain. That round wasn't in the inventory back in my day. As to the picks of the original VN era 113, they had lighter armor. When did that HEDP round come out?
Link Posted: 1/22/2006 2:45:38 PM EDT
The HEDP is rated against steel, not aluminium (even milspec aluminium). It will penetrate.

The munroe effect says that range and velocity are unimportant. Warhead size rules, and generally speaking any well-made shaped charge can actually penetrate 3-5 times its diameter. The rating ensures that the round still has lethality once a penetration occurs.

I used these all the time in the 80s when doing work for a foreign govenrment. We'd get border incursions by guys in BTR-50 and BTR-60. The 40mm was a primary weapon against those targets. And my 'sponsor' bought gazillions of them!



The 20mm Oerlikon I had the in the CG V-150 turret was my favorite penetrator!!
Link Posted: 1/22/2006 2:46:19 PM EDT

Originally Posted By raven:

Originally Posted By ArmdLbrl:

Originally Posted By raven:
Took 5 rounds.



Wow that few? Did you get a engine kill or start some sort of fire?



This is in a PC game. The driver jumped out and the thing started smoking after 5 hits.



OOOH you, use a smiley face if your going to post something like that so we know your not serious.
Link Posted: 1/22/2006 2:49:25 PM EDT

Originally Posted By ArmdLbrl:

Originally Posted By eodtech2000:

Originally Posted By PsyWarrior:
Perfect hit in just the right place on a track with an HE round or through an open hatch and yes, it can take out a 113. However, a 40mm round of any type will not pierce the armor on a 113.



A HEDP will cut a hole in it like a hot knife through butter. Shaped-charges have no problem penetrating a M113.

You should see what a Maverick does, little shaped-charge holes my ass.



It will go through but like a hot knife through butter is a bit much. It wont make much of a hole.

The grenades are rated for 50mm at 0deg The M113 is 38mm thick. Even the 57mm HEAT that made the hole in that picture I posted above was rated at 80mm penetration, and look at all the bigger hole it made. Where its located it probably went into the engine and disabled it but its unlikely it killed anyone.



Even the bigger shaped-charged warheads will make a similiar sized hole but they put a hell a lot more jet (hot gases/molten copper) into the interior. Granted, I personally think a 40mm HEDP would do insignicant damage unless it was fired in bunches from a Mk-19 or got a lucky hit.

One also has to take in account that the M-113's armor is aluminum not steel, most shaped-charge warhead penetration tests are on hardened steel not the much softer aluminium.
Link Posted: 1/22/2006 2:51:20 PM EDT
[Last Edit: 1/22/2006 2:54:17 PM EDT by Warrior-Poet]
Picattiny developed the improved rounds in the 70s. They saw limited use in RVN (mostly in AH-1).

That 57mm hit demonstrates the aluminium issue: the round probably did a lot more damage in the engine compartment since the chassis dodn't cause much of a slowdown. The 'splash' characteristic of a HEAT/Munroe charge is pretty extensive on this hit: not a very well-designed warhead.

I'd still rather avoid getting hit by one.
Link Posted: 1/22/2006 2:53:43 PM EDT

Originally Posted By Warrior-Poet:
The HEDP is rated against steel, not aluminium (even milspec aluminium). It will penetrate.

The munroe effect says that range and velocity are unimportant. Warhead size rules, and generally speaking any well-made shaped charge can actually penetrate 3-5 times its diameter. The rating ensures that the round still has lethality once a penetration occurs.

I used these all the time in the 80s when doing work for a foreign govenrment. We'd get border incursions by guys in BTR-50 and BTR-60. The 40mm was a primary weapon against those targets. And my 'sponsor' bought gazillions of them!



The 20mm Oerlikon I had the in the CG V-150 turret was my favorite penetrator!!



The only instances I have seen in print with 40mm GLs vs armored cars involved Mk 19s. Now thats basicly the same projectile, but you are hitting it multilple times per burst. If a Mk 19 can keep a M113 in its sights for two seconds or so I have no doubt it could torch it with a dozen or so hits.

I dont think it would often be a one shot one kill weapon unless you had some really old AFV that still had a gasoline engine. How many times did you have to hit a BTR to get it to stop or burn? I think they have diesel engines and are steel construction aren't they?
Link Posted: 1/22/2006 2:59:21 PM EDT
We did usually use multiples (the indigenous security forces were enthusiastic, and pretty good w/ the GLs). The BTR-60 is steel, all-welded, and only 7mm to 9mm thick IIRC (old memories). For a small honker, they weighed like 10 metric tonnes. I don't recall any one-shot-kills, but I was usually organizing the fight, and not shooting one. I used the 20mm when I had to.
Link Posted: 1/22/2006 3:07:00 PM EDT

Originally Posted By Warrior-Poet:
We did usually use multiples (the indigenous security forces were enthusiastic, and pretty good w/ the GLs). The BTR-60 is steel, all-welded, and only 7mm to 9mm thick IIRC (old memories). For a small honker, they weighed like 10 metric tonnes. I don't recall any one-shot-kills, but I was usually organizing the fight, and not shooting one. I used the 20mm when I had to.



They were pretty good as well as enthusiastic. Its hard to hit a moving something at any great range with a projectile that only moves 250fps and isnt steerable!
Link Posted: 1/22/2006 3:07:24 PM EDT
I remember some moron Col. in the USAF Security Police told me I could me I could knock out a Soviet APC with a M203 40mm round if I got within five feet. I told the walking eagle that the round needed three times that distance to arm itself. He gave me a "I just pissed on myself" look, and walked away. My flight Flight Chief made sure I got only the shitiest posts after that, until the next guy fucked up.
Link Posted: 1/22/2006 3:16:07 PM EDT

Originally Posted By ArmdLbrl:

Originally Posted By Warrior-Poet:
We did usually use multiples (the indigenous security forces were enthusiastic, and pretty good w/ the GLs). The BTR-60 is steel, all-welded, and only 7mm to 9mm thick IIRC (old memories). For a small honker, they weighed like 10 metric tonnes. I don't recall any one-shot-kills, but I was usually organizing the fight, and not shooting one. I used the 20mm when I had to.



They were pretty good as well as enthusiastic. Its hard to hit a moving something at any great range with a projectile that only moves 250fps and isnt steerable!



So long as it's moving at a fairly constant speed in a fairly straight line it wouldn't be too terribly difficult.
Link Posted: 1/22/2006 4:26:17 PM EDT

Originally Posted By ArmdLbrl:

They were pretty good as well as enthusiastic. Its hard to hit a moving something at any great range with a projectile that only moves 250fps and isnt steerable!



OK. that's what training is for.
Link Posted: 1/22/2006 4:45:30 PM EDT
I don't see why a 40mm HEDP wouldn't penetrate an M-113 - especially with aluminium armor.

How much of a difference would the kevlar spall liner make on the M113A3? I remember it doing fairly well in the box o truth against pistol rounds. How well would it do against a 40mm round after it had already gone through the 2 inches of aluminium and 18 or so inches of open space?


-K
Link Posted: 1/22/2006 6:21:52 PM EDT
[Last Edit: 1/23/2006 2:32:10 PM EDT by Warrior-Poet]
Kevlar is not proof against the plasma formed by the Munroe effect. Kevlar cuts down on spall, which by definition is the after-effect of mechanical strikes by kinetic weapons or squash-head/HEP warheads. Kevlar is next to useless against HEAT, except it'll cut down on the secondary missiles that spall off the inside of the armor. But the primary effect of heat energy will continue expanding insisde the vehicle. It is for this reason that ERA is used: it triggers the HEAT warhead, which expends itself burning up the standoff distance. Any mechanical (kinetic) projectiles are subsequently defeated by the kevlar liner, up to the point of over-kill by the warhead.

Yes, I am a weapons systems engineer.
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