Mummert later led the 14th Panzer Reconnaissance Battalion of the reformed 14th Panzer Division, the original having been destroyed in the Battle of Stalingrad. His leadership style often saw him on the frontlines with his infantry and engaged in close combat, and he received several badges in recognition of this; the Panzer Badge and Close Combat Clasp, both in bronze, as well as the Tank Destruction Badge for Individual Combatants. He was given command of the 14th Panzer Division's 103rd Panzer Grenadier Regiment in January 1944.
Mummert later commanded the 14th Panzer Reconnaissance Battalion of the reorganized 14th Panzer Division, which had been rebuilt after being destroyed in the Battle of Stalingrad. His leadership approach frequently placed him on the frontlines with his infantry and involved direct combat, earning him several awards; the Panzer Badge and Close Combat Clasp, both in bronze, as well as the Tank Destruction Badge for Individual Combatants. He was appointed commander of the 14th Panzer Division's 103rd Panzer Grenadier Regiment in January 1944.