Panzer IV
The first known proposal for a Sturmgeschütz on the Panzer IV chassis is in Krupp drawing number W1468 dated February 1943. This initial drawing unitized the outdated Sturmgeschütz Ausf. F superstructure on a Panzer IV chassis. This proposal had a sloped front superstructure with a combat weight of 28.26 tons. Krupp abandoned it in February 1943 because it was too heavy. Plans for the StuG IV were halted.