"The M42A1 Duster’s Crucial Role in the Vietnam War" Topic

"U.S. Army First Lieutenant Bruce Geiger participated in the protracted siege of Khe Sanh during the Vietnam War. For 77 days, the United States 26th Marine Regiment withstood the assault of three North Vietnamese Army divisions. During the famous siege, Geiger commanded A Battery from the 1st Battalion, 44th Artillery (1/44th), a U.S. Army air defense artillery battalion attached to the 3rd Marine Division, the parent unit of the 26th Marine Regiment.

A pair of M42A1 Dusters proved to be valuable components in the defense of the combat base's airstrip. Positioned at either end of the airstrip with a company of entrenched Marines between them, the Dusters were greatly admired for the heavy firepower furnished by their twin-mounted 40mm Bofors guns. Geiger's battery was augmented by four truck-mounted .50-calibre machine guns known as Quad-50s…."
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Armand

I suspect anything from War Thunder for accuracy.

Used to play, but when a Whirblewind took out my brand new T-34 from the front with 20mm cannons in one burst, I knew that "accuracy" was not what they were looking for.

I remember a funny story about a M-24 Duster in the Vietnam War. 3 veteran (short) grunts were coming back into the FSB and noticed a Duster put in the defense line. Not having seen one before they asked the crew if that puts out a lot of lead.

"No lie, GI" was the reply and cleared for a demonstration of the twin 40mm guns power.

After watching the jungle and hillside get ripped up, the crew asked the Grunts what they thought.

"We're going far away from you. That is going to draw a lot of fire if we get hit".

Veteran infantry see what really matters.

There is also another account in a Keith Nolan book (don't remember which one, ALL are great) of 3 M-42 getting sent into a road ambush without infantry support by a Lt.

The gomers swarmed over them in a minute and killed every one of the crewmen.

Inspired leadership.

Oddball brings up good points. It is pretty obvious that the weapons that draw fire from an enemy are the lethal ones that the enemy needs to eliminate. Just like WWIII with the mhine gun in a German infantry squad. That was what you needed to eliminate. If anything, drawing fire is a confirmation of the effectiveness of the M42.

Being overrun by infantry is not surprising if they had no infantry support of their own. An ambush is a good way to do it.

One can say the same thing about a battery of 105mm howitzers. And it is true. One can also say the same thing about a tank. Again it is true.

I have over 300 books on the war in Vietnam. With few exceptions they are "down in the weeds" or "grunt level" books. From all of my reading the dusters were terribly effective weapons against enemy troops. But like artillery and tanks, they have their vulnerabilities.

Tom

For anyone interested in the experience of the Duster in combat I'd recommend "Black-Horse Riders" by Phillip Keith. He details the unfortunately overlooked rescue of a trapped American infantry company that had stumbled into an NVA bunker complex by Alpha Troop, 1st Squadron, 11th Armored in March, 1970 along with an attached infantry company. When they arrived at the bunker complex they lined up the Dusters and let loose with canister rounds, which completely denuded the jungle, exposing the bunkers.

For some reason this action was all but forgotten until the units were finally recognized 2009 with unit citations. What I found somewhat surprising is that it was only in 1970 that apparently the army decided to pair armor units with infantry units so they could train cooperatively…the units involved in the rescue were part of that training exercise.

Many thanks!

Armand

I read somewhere that Dusters did 'rude things' to PT76's.

A pea-shooter could do "rude things" to a PT76. The Duster could deafen you and/or knock you out of your hammock if it was firing within 100 feet, which could probably be called "rude things" to friendly forces.

LT

brass1,
M72 LAW's bounced off PT-76's many times at Lang Vei.

Others formed anti-tank squads using the LAWs to try and destroy the NVA PT-76 armor. Unfortunately, the LAWs often malfunctioned or misfired. Even direct hits on the Soviet-made tanks merely bounced off the armor without detonating, but at least one additional tank was destroyed through their efforts.

Wolfhag

That's because the LAW was a piece of junk that would bounce of a turtle. I have never heard anyone who though it was worth the energy to pick it up and the Pentagon claim that one could pierce 13 inches armor would cause either laughter or swearing.

Now, hit the tank commander in the eye with a projectile from a pea-shooter could cause damage, even more if it is was attached to another projectile from a 106mm recoilless rifle.

LT

(smile)

Armand

If you look at the frontal profile of a PT-76 it's not surprising that any round would not bounce off. Although a low velocity spitball may stick and leave a rust mark. Since the PT-76 has a two-man turret the commander needs to be buttoned-up when firing so he's safe.

The 106's at Lang Vei probably fired point detonating HE rounds to knock out the tanks. I think one PT-76 was claimed by a LAW. A Duster would have done well against them with HE too.

The early LAW's were a POS against armor but did well against bunkers. I fired them a number of times on the range in the early 1970's and didn't see any malfunctions. Probably A1 and A2 models. Although, the early ones did have a problem with the warhead going off mid-flight and sometimes falling out of the tube. Just like any new weapon, it had its teething problems. However, the design has been improved and is still in use today.

Wolfhag

"66"LAWs were handy for taking out Argentinian trenches and sangars in 1982.

Do they still penetrate 13 inches of armor?

I saw a bunch of scared ARVN grunts running down QL1 as fast as they could during the Easter Offensive and if one stopped to see if we had water he would he would gripe that they were told that the NVA didn't have tanks (this was US intelligence which was stupidly wrong. The tanks were spotted by a reporter from UPI who was hitching a ride on a LOACH and reported to Corps)

The LAWS were among the first weapons the ARVNs threw away because they were heavy and they bounced on the enemy tanks.
One of the few ARVNs who said anything in English said "Rockets all s*** You don't want get kill throw in paddy and run with us."

LT

From what I have read of LAWs in Vietnam, the principal problem with them seem to have been the failure of the Army to tropicalize both the weapon and its storage packaging.

The WW2 lessons learned in the tropical environs of the PTO were apparently forgotten over the course of twenty short years.

- – -

What has also long puzzled me is why the US never swallowed its pride and copied/adapted the inexpensive, man-portable, easily handled RPG-7 multi-purpose weapon system. It seems to me to have been a lot handier and less bulky than the 3.5-in bazooka.

B

brass1,
If you look at the technical progression of the M72 you'll see it's a different weapon than the first model developed with 1950's technology. Regarding using it against tanks in 1968, I'd probably throw it away too. They had the same ricochet problem with the first warhead design and fusing on the 2.36" bazooka. It was brought back to use in an urban environment, not against tanks and it was useful in VN against bunkers. The 3.5" Bazooka could take care of the tanks.

Blutarski,
When the M72 came out we already had the 3.5" Bazooka developed at the end of WWII. I think the idea of the M72 was a way for every soldier to carry one or two disposable shots and it replaced rifle grenades. The US was also deploying the M79 grenade launcher too. I've carried a 3.5 and it's not easy to set up and shoot, the RPG is easier. It breaks down into two pieces but can be assembled easily. It did pretty well in Korea. The RPG would be much easier and more stealthy to use.

An advantage of the M72 is that you could salvo fire it as each member of a squad could be carrying one or two.

The RPG was normally a crew served weapon with a gunner and ammo carrier.

The Russians must have thought that the M72 was a good ideas as they copied it in the 1980's with the RPG 18, 22 and 26.

As to why NATO never adopted an RPG type weapon I'm not sure.

Wolfhag

Thanks!.

Armand

Yes, I had read the US Army ADA M42s & quad .50s performed very well at Khe Sahn. Were good anti-Infantry weapons. The French at DBP also a few quad .50s too.

As Wolf posted … The first M72s had the problem with the warhead falling off the rocket in flight. We were trained to read the data painted on the tube. IIRC if it didn't say M72A2 w/coupler. Don't use it. The later version of the M72 had the coupler added to it during it's production. At the factory back home. And solved the warhead falling off …

Being overrun by infantry is not surprising if they had no infantry support of their own.

Yes without Infantry support in closed terrain it is generally easy to overwhelm AFVs. The M42 was designed primarily for AA. The open turret was not a problem when not in the "frontline" per se. However, it is particularly at a disadvantage with the open turret. If it was deployed alone, too close to the "front". As we see …

As a Infantryman/Officer '79-'90, we and our troops were trained to go tank hunting, perform AT Ambushes etc. If AFVs rolled thru a wooded road or MOUT, etc. Without Infantry support. They could be quickly KO'd.

My M113 Mech Co. was frequently attached to a Tank Bn. Our primary function was to work closely with/support the M60s & M1IPs MBTs. And vis versa. Using combined arms doctrine, etc.

At night at times we were sent to a nearby village, etc. to find & kill the OPFORs' MBTs/AFVs. We did a successful night AT Raid on a OPFOR Canuck Co. of Leos. During REFORGER '88. They had no Infantry support, laagered in an NDP in a little German village.

Regarding the open turret. It's my understanding all AA guns needed an open turret to observe and keep gases from building up inside an enclosed turret and choking the crew.

Wolfhag

Yes, that is the way and what it was designed for – ADA … Open turret was for crew observability and the gun's ability to raise at high angles of fire to engage aircraft.

ZSU 23 4 managed a closed turret, but much smaller calibre weapons of course. Must agree that, for AA work the open top has huge advantages.

deadhead,
You are right about the Shilka. It needed to be enclosed for NBC protection. Open top is not needed if you have a radar controlled gun. Also, the bulges on the front shoulders of the turret are cooling/ventilation shrouds. Their effectiveness would most likely depend on the volume of fire.

The ZSU-57-2 was open top.

Wolfhag

Open top is not needed if you have a radar controlled gun……

Now that is genius. Begs the Q "Why didn't I think of that?"

ZSU 23 4 managed a closed turret, but much smaller calibre weapons of course. Must agree that, for AA work the open top has huge advantages.

IIRC the ZSU 23 4 was designed after the M42 ? Yes, as I mentioned in many cases an open turret for AA is an advantage in most situations.

The ZSU-57-2 was open top.

Yes, again date of design and requirements, etc. is always a factor.

E.g. US TDs in WWII were all opened top. Because of the tech at the time. Later after WWII some M36s had an armored top deck added to the turret like most other AFVs.

Open top is not needed if you have a radar controlled gun……

Yes but as we know not all AA had that option until later dates of design, etc. The best they had was the Mk.1 Eyeball 👁

harder to NBC seal an open-topped vehicle

Yes, the crew will have to do like the Infantry. And go into MOPP level 3 or 4.

How it's possible that WWII's lessons had been forgotten? In PTO marines & infantry had to support tanks because there was always the menace of suicidal attacks from the japs with varios systems, and close support from infantry in difficult/urban terrain it's indispensable, expecially with open turrets such as for the M42.

The M42 was not really designed for front line/assault ops. It is an ADA weapon which was to be used far enough behind the frontline/FEBA, etc. where the open turret would not be a problem.

It was "shoehorned" into anti-Infantry ops, as the NVAF had few aircraft that were to be used for CAS. AFAIK they never did attack ground targets ? But the high rate of fire of the M42s Twin 40mm made it useful in taking out massive waves, etc., of infantry. Which as we know the VC was nothing but Light Infantry with support weapons, mortars, etc. And NVA was similar, being an Infantry heavy army, which had mortars, FA, etc., however little Armor. But they did have some which really saw more action in the later phases of the war. When the NVA pushed South, etc.

The US Army M42s at Kah Sahn along with US Army Quad .50s mounted on trailers towed by trucks, etc. Were not that close to "the wire", as they had long range weapons' fires. E.g. an M2 .50 cal has a max range of about 6800m.

And yes, the US Army was at Kah Sahn too …

Had the defenses at Kah Sahn been total overrun these M42s and quad .50s may have been easy targets for massed NVA Infantry attacks and even mortars, FA, etc. Of course, the M42s and Quad .50s would has cost the NVA dearly. If they tried to close assault the vehicles, etc.

However, in some cases in other locations, the M42s were not in a defensive position like Kah Sahn. They did usually have infantry support, etc. But the M42s would be prime targets for RPGs/B40s. The VC/NVA did not have to get close enough to attack the M42's exposed crew with hand grenades, etc. AFAIK no M42 was destroyed by Infantry close assault. But it appears they were hit with mines/booby traps and/or RPGs/B40s, etc. As well as the crew may have been hit by SA fires.

I know of one case a Marine who served in Vietnam and was there. As an Army M42 was supporting the USMC moving along a road to clear/secure,(?) etc. As soon as the Marines and M42 were taking fire/ambushed(?).

The M42 got out of the area ASAP, as the TC knew how vulnerable it was with Infantry being that close by. The Marines were not happy about that. But the M42s TC knew he was in the wrong place at the wrong time.