The Skysweeper was introduced just as surface-to-air missiles were being deployed in the long-range role, replacing earlier anti-aircraft artillery systems.

The Army's existing guns were a motley collection of World War II-era systems that were barely effective then and were considered largely useless against jet-powered aircraft.

By that time newer missile systems were closing the range gap, and the Army was busy developing new weapons like the MIM-46 Mauler for this role.

At very low altitudes there were only seconds in which to react when spotting an aircraft over local terrain, so a hand-swung weapon was the only possibility, no matter how inaccurate.

This led to the need for a new gun to address this intermediate-range role, and the Army defined this to be a weapon able to defeat aircraft flying at 1,000 mph (1,600 km/h) at altitudes up to 20,000 feet (6 km).

A new 75 mm gun, known as the T83E1 or M35, was developed that had excellent muzzle velocity, along with two ten-round revolver-type magazines and an auto-loader that allowed it to reach 45 rounds/minute—about one third of what the much lighter Bofors had managed.