Al the ranges of the halftrack family were to be replaced. That was a constant process. The HK-600 range was to replace all existing light and medium halftracks. HK means Halbkette, Halftrack, HKp means HalbKette gePanzert, armored halftrack. Development starts in 1939 and ends in 1942. Apart from the 603 that stands more or less on its own and is a direct descendant of the 251 all others seem to be "developers-dreams". The best there is to built; fully new designs.
Hanomag builds 7 during 1939/1940. It has a HL45Z 6 cylinder 120 hp engine and a Hanomag pre selective transition. Steering brakes are hydraulic. Road brakes are pneumatic. Suspension is torsion bar. Crew of 8. Weight 6.3 tom fully loaded. It carries 1.5 ton and tows 4.5 ton. Road speed 47 mph max.
Armor is added to the hk601 in 1940 by Demag. 1942 sees 3 + 9 prototypes. Frontal armor 14mm. 12 men are to be seated.
The HKp 603 follows soon. It has a Maybach HL45Z and again never leaves the prototype stage. The HKp 603's body is based on that of the 251. The vehicle weighs 8 ton.
Demag builds 30 in 1941/42. The body is partially armored. With a Maybach HL 50 6 cylinder 170 Hp engine, Maybach Olvar and pre selective transmission, Pneumatically operated Argus-type brakes. Suspension is torsion bar. trailer load 4.5 ton, road speed max 48 mph. A total weight of 6.8 ton is achieved.
Designed by Demag this again is to replace al 3ton vehicles. A fully armored version of the HKp 605. The picture is said to show a mock-up armor.
This project of Hanomag never leaves the drawing board. It is a further development of the 605 line weighing 9.5 ton.