page_title: M42 Duster
section_title: Vietnam War
hierarchical_section_title: M42 Duster / Service history / Vietnam War
caption_attribution_description: English: M 42 Duster, MACV compound at Quang Tri City, February 1968.
context_page_description: The M42 40 mm Self-Propelled Anti-Aircraft Gun, or "Duster," is an American armored light air-defense gun built for the United States Army from 1952 until December 1960, in service until 1988. Production of this vehicle was performed by the tank division of the General Motors Corporation. It used components from the M41 light tank and was constructed of all-welded steel.
  A total of 3,700 M42s were built. The vehicle has a crew of six and weighs 22,500 kg fully loaded. Maximum speed is 45 mph with a range of 100 miles. Armament consists of fully automatic twin 40 mm M2A1 Bofors, with a rate of fire of 2×120 rounds per minute and either a .30 caliber Browning M1919A4 or 7.62mm M60 machine gun. The 500 hp, six-cylinder, Continental, air-cooled, gasoline engine is located in the rear of the vehicle. It was driven by a cross-drive, two-speed Allison transmission.
  Although the M42 Duster was initially designed for an anti-aircraft role, it proved to be highly effective against unarmored ground forces in the Vietnam war.
context_section_description: The HAWK missile system performed poorly in low altitude defense. To ensure some low altitude anti-aircraft capability for the ever-increasing amount of forces fielded in Vietnam, the Army began recalling M42A1s back into active service and organizing them into air defense artillery (ADA) battalions. Starting in the fall of 1966, the U.S. Army deployed three battalions of Dusters to the Republic of Vietnam, each battalion consisting of a headquarters battery and four Duster batteries, and each augmented by one attached Quad-50 battery and an artillery searchlight battery.
  Despite a few early air kills, the air threat posed by North Vietnam never materialized and ADA crews found themselves increasingly involved in ground support missions.  Most often the M42 was on point security, convoy escort, or perimeter defense.  The "Duster" (as it was called by U.S. troops in Vietnam) was soon found to excel in ground support.  The 40 mm guns proved to be effective against massed infantry attacks. According to an article that appeared in Vietnam Magazine:
  M-55s and M-42s were old pieces of equipment that needed a lot of maintenance and required hard-to-get spare parts. The gasoline-powered Dusters were particularly susceptible to fires in the engine compartment. Thus, despite its cross country capability, it was not wise to use the Duster in extended search and destroy operations in heavy jungle terrain because of excessive wear on engines, transmissions, and suspensions.
  On the plus side, the Duster was essentially a fairly simple piece of machinery on which the crews could perform maintenance. Better yet, the Duster's high ground clearance and excellent suspension-system design gave it an ability to withstand land mine explosions with minimal crew casualties.
  Although the Duster's 40mm shell had a terrific blast and fragmentation effect, it also had a highly sensitive point-detonating fuse that limited effectiveness in heavy vegetation. Under those conditions, the better weapon was the Quad, because the heavy .50-caliber projectile could easily punch through cover that would detonate the Duster's 40mm shell too early for it to be effective. At long ranges, however the 40mm shell was far more useful, particularly against field formations. The Duster also was able to deliver indirect fires by using data from field artillery fire-directions centers.
  
  Soldiers of the 1-44th Artillery and their Marine counterparts in I Corps set the pattern of Quad and Duster operations. Because of an early scarcity of armored-combat vehicles, M-42s were first used as armor. Often thankful men quickly learned the value of high volumes of 40mm and .50-caliber fire, both in the field and perimeter defenses. Quads beefed up the defenses of remote fire bases, while Dusters accompanied both supply and tactical convoys along contested highways to break up ambushes. Dusters of Battery C, 1-44th Artillery, led the task force of Operations Pegasus that broke the siege of Khe Sanh in April 1968. Dusters and Quads provided critical final-protective fires throughout Vietnam during the Tet offensive and later took part in Operation Lam Son 719. Whenever fire support was needed, M-42s and M-55s could be found.
caption: M42 Duster, MACV compound at Quảng Trị City, February 1968.
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