In March of 1942 the reequipping of the Panzer III with the rotating turret of the Panzer IV was debated. With concern for the resulting problems, such as strongly increased gross weight, new running gear, new tracks and weight distribution. The Panzer III was to continue in production with the 50mm KwK L/60, but production of the Panther tank was to replace the Panzer III as soon as possible, since the Panzer III no longer possessed its old fighting value. Hitler considered it possible in view of the favorable production conditions for Panzer III and Panzer IV to let production of the former continue at full capacity.
On April 4, 1942 Hitler was shown the Panzer III with the 50mm Pak 38 gun. The gross weight of the Ausf. M series of the Panzer III, which began in 1942, was 21,130 kp. Its Daimler-Benz designation was "1O/ZW", its chassis numbers from 76 001 to 78 000. A basic change in the exhaust system made the vehicle capable of wading to a depth of 1.3 meters. The price of this version (without armaments) was 96,183 Reichsmark per vehicle.
At the end of 1942 Hitler ordered an investigation of the extent to which cessation of Panzer III production could be balanced by a corresponding increase in Sturmgeschlütz (assault gun) production. On the basis of the reported possibility for switching production, Hitler decided on December 1, 1942 that, instead of the Panzer III, production of the Sturmgeschlütz should be expanded beyond previous plans, from 120 units in December 1942 to 220 units by July of 1943. In 1942, 2555 "ZW" vehicles were completed.