The M42 40 mm Self-Propelled Anti-Aircraft Gun, or “Duster,” is an American armored light air-defense gun
Production of the M42 began in early 1952 at GM’s Cleveland Tank Plant. It entered service in late 1953 and replaced a variety of different anti-aircraft systems in armored divisions.
In 1956, the M42 received a new engine and other upgrades along with other M41 based vehicles, becoming the M42A1. Production was halted in December 1960 with 3,700 examples made during its production run.
Construction called for all welded steel. Most of the components came from the M41 to keep the cost down, and the compartmentation was unchanged, with the driver located at the front, central fighting compartment with the M42 turret seated on the original turret ring location, albeit larger, and rear engine compartment.
The turret was open to allow maximal visibility, but the armament was shielded, protecting the front against retaliatory strafing attacks. However only the pointers and gunners had some protection, the loader remained exposed.
The Armament consisted of fully automatic twin 40 mm M2A1 Bofors, which had a rate of fire of 120 rounds per minute. In addition, for close defense, a 7.62mm Browning M1919A4 or a M60 machine gun could be installed on a side pintle located at the right-hand side of the turret.
To maximize effectiveness, it was thought these vehicles could be assisted by a single M42 converted as radar fire control system, but the project was dropped because of cost issues.
In Vietnam war, 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 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.
The Viet Cong called them “Fire Dragons,” because their high volume of fire and tracer ammunition gave the appearance of a dragon’s breath. Their U.S. Army crews called them “Dusters,” due to the large clouds of dust they created as they sped across the dirt roads of Vietnam.
The original purpose when joining the war in Vietnam was air defense. However, due to the absence of an airborne threat from North Vietnam, the US military used M42 to serve on bases or escort convoys. Gradually, the American army discovered that, with two 40mm guns, the vehicle proved to be effective against massed infantry attacks. And because of its high chassis and very good suspension, the M42 tank was capable of the ability to surf fiercely and be less damaged by the mines of the Liberation Army.
In total, roughly 200 M42 Dusters saw service throughout the entire war. Three battalions were retired in December 1971, but at that stage, surviving vehicles were passed onto the Army of the Republic of Vietnam forces.