During the war, the Americans need a mobile anti-aircraft gun. The popular M16 MGMC was the best solution for fast and cheap production. This was a M3 halftrack equiped with a Maxson M45 Quadmount AA-gun. Those are four .50 M2HB Browning machineguns with a high rate of fire but each shot was not very powerful. Another weapon, the M1936 Bofors had also done a great service during the war. It had a low rate of fire, but it was powerful. Because of this, the Americans used this gun to equip a number of vehicles. Another M3 Halftrack variant was the T54E1 but it was very unstable when its fired. So there was again a need for new vehicles. The solution was a vehicle which will be followed by the M42 Duster and that was the M19 GMC based on the M24 Chaffee chassis. The turret was removed and replace by a new open turret with two shields. Because they moved the engine from the back to the front, it was possible to place the turret on the back. The guns are two 40 mm Bofors M1936 AA-guns. Only 285 were built. Though the M42 which superceded was basically the same concept but on the M41 light tank which thus replaced the M24 Chaffee in all its uses.