Possibly the most successful short range anti-aircraft gun of the 20th century wass the Bofors 40mm gun. It’s been fired from ground mounts, trucks, armored vehicles, ships and even airplanes.
One of the more successful mountings was the marriage of a twin gun mount onto the chassis of the M41 light tank, leading to the M42, commonly known as the Duster.
Now, US troops haven’t been under aerial attack much since World War II. But the Duster’s good rate of fire and explosive projectiles made it a popular direct fire support weapon in Vietnam.
The Duster was eventually replaced by the M163 Vulcan 20mm tracked vehicle.