The Karl howitzer needed vehicles that could transport their ammunition and help load them. The 60 cm ammunition weighed 4,794 lb / 2,170 kg and the 54 cm weighed 2,756 lb / 1,250 kg.
PzKpfw IV Ausf F chassis were used. The basic hull was used with a platform built on it. There was space for two or three shells.
The Munitionpanzer would transport the shells from train cars to the Karl's firing position by parking next to the breech and loading shells by a crane.