In October 1940, the Ausf H (7-serie) entered production. It was produced by MAN, Alkett, Henschel, Wegmann, MNH and MIAG until April of 1941 with 308 produced (chassis numbers 66001-66650). The Ausf H featured a newly designed turret to mount a 50mm gun with a single 30mm armor rear plate. Armor protection ranged from 10mm to 30mm, but hull, front and rear, as well as the superstructure front had 30mm armor plates bolted on to them increasing the protection. The increase in armor protection in the Ausf H neutralized the threat of British 2pdr, Soviet 45mm and American 37mm anti-tank guns. The new six speed Maybach SSG 77 gearbox replaced the previously used Variorex. In addition, the suspension system was slightly modified and new sprocket and idler wheels were used in the Ausf H. Consequently, because of the weight gain to 21.8 tons, due to the increase in armor protection, torsion bars were strengthenedd. Originally, the Ausf H was armed with a 50mm KwK 38 L/42 gun and two MG 34 machine guns, but in 1942/43, they were rearmed with a50mm KwK 39 L/60 gun.
Ausf E, F, G and H were designated as Panzerkampfwagen III Ausf E, F, G and H / Sd.Kfz.141. As of May 10th 1940, the Panzertruppe had only 381 Panzer III models in service, but 135 were lost during the Blitzkrieg in the west.
In March 1941, the last Sd.Kfz.141 and the first Sd.Kfz.141/1 Panzerkampfwagen III tank - Ausf J (8-serie) entered production. It was produced by Daimler-Benz, MAN, Alkett, Henschel, Wegmann, MNH and MIAG until July 1942 with 2616 produced (chassis numbers 68001-69100 and 72001-74100). The Ausf J had its armor protection significantly improved and it ranged from 10mm to 50mm. The increase in armor was accompanied by the installation of the new driver’s visor (Fahrersehklappe 50) and a ballmount (Kugelblende 50) for a 7.92mm MG 34 machine gun in the hull. A new type of front access hatch was installed along with new air intakes on the hull front. From April 1942, 20mm spaced armor was added to the gun mantlet and/or superstructure front. 1549 vehicles produced from March 1941 to July 1942 were armed with a 50mm KwK 38 L/42 gun and two MG 34 machine guns. Those vehicles were designated as PzKpfw III Ausf J / Sd.Kfz.141. 1067 vehicles produced from December 1941 to July 1942, were armed with 50mm KwK 39 L/60 and two MG 34 machine guns. Those vehicles were designated as PzKpfw III Ausf J / Sd.Kfz.141/1. The only difference between these models was the main armament and ammunition stowage for 84 rounds in contrast to the previous 99 rounds. When encountered in North Africa, the British nicknamed the 50mm L/60 Ausf J the "Mark III Special". The 50mm L/60 gun was a significant improvement over the original 37mm gun, although it was still inadequate to deal with American M4 Sherman and Soviet T-34/76 tanks. In 1941/42, there was an unsuccessful attempt by Krupp to mount the Ausf J with Panzerkampfwagen IV Ausf G’s turret to create a new Panzerkampfwagen III variant designated Ausf K.
From August to November 1942, 81 Ausf J tanks were produced as command tanks - Panzerbefehlswagen III mit 5cm KwK L/42 / Sd.Kfz.141. From March to September 1943, an additional 104 Ausf J were converted as well. The vehicle was the basic Ausf J tank but it lacked a hull machine gun and carried less ammunition (75 rounds). It was fitted with additional radio equipment and periscope.
In June 1942, the Ausf L tank entered production. 653 were produced by Daimler-Benz, MAN, Alkett, Henschel, Wegmann, MNH and MIAG until December 1942 (chassis numbers 74101-75500). The Ausf L was armed with a 50mm KwK 39 L/60 gun and two 7.92mm MG 34 machine guns. Externally it was almost identical to the late model Ausf J as it was developed by modifying it. The main difference was the new torsion bar gun counter balance, which replaced the original coil spring gun recoil mechanism. Armor protection of the front turret was increased from 30mm to 57mm and 20mm spaced armor was installed on the superstructure front, and in many cases on the gun mantlet. The design of the vehicle was simplified as the rear deck was modified (air-intakes and hatches) and early in production the hull escape hatches, the loader’s vision port on the mantlet and turret side ports were removed. The Ausf L was also mounted with a new special system to transfer heated engine coolant from one vehicle to another. A single Ausf L was mounted with an experimental 75/55mm tapered-bore KwK0725 gun and was designated as PzKpfw III Ausf L mit Waffe 0725. Vehicles send to North Africa were equipped with additional air filters, modified oil filters, a different cooling fan reduction ratio and were designated as Ausf L(Tp). The Ausf L was also first to be mounted with an anti-aircraft machine gun mount (Fliegerbeschussgerat 41/42) on the commander’s cupola. This became standard on all new PzKpfw III tanks and was mounted on older models during service. Many were mounted with 5mm hull and turret armor skirts (Schurzen).
From October 1942 to February 1943, 250 new Ausf M (10-serie) tanks were produced by Wegmann, MIAG, MAN and MNH (chassis numbers 76101-77800). The Ausf M was a late production model Ausf L mounted with new wading equipment allowing wading up to depth of approximately 1.3m, in contrast to the previous 0.8-0.9m. This led to all air inlets and outlets as well as other openings and joints being sealed, while a modified muffler with closure-valve was installed high on the hull rear. The new system was developed and a modified version was used in Tauchpanzer III submersible wading tanks. The hull rear mounted rack of five smoke generators was replaced by three 90mm NbK dischargers mounted forward on both sides of the turret. The Ausf M just as the Ausf L was armed with a 50mm KwK 39 L/60 gun and two 7.92mm MG 34 machine guns. Vehicles produced in 1943 were factory mounted with 5mm hull and turret armor skirts (Schurzen). Large number of Ausf M were converted to either Sturmgeschütz III or Ausf N.
GERMAN TANK RUBBER ANALYSIS
Analysis by British engineers of samples of natural and artificial rubber taken from the PzKw 3 tanks discloses some interesting points which are worth recording.
Two very similar articles, i.e. a vision forehead pad and a cupola pad of a 1940 model of this tank proved to be very different when analyzed. The former was made of natural rubber and was secured to the metal by the brass plating process. The cupola pad, on the other hand, was made from synthetic rubber and was attached to the metal by an adhesive paint. These samples confirm the previous supposition that the Germans have not yet learned how to make an efficient joint between synthetic rubber and metal.
The most interesting sample, however, was a section of a bogie wheel tire from a PzKw 3 tank (probably 1942). This sample proved to be made of synthetic rubber. This is said to be the first evidence received by the British authorities of this material being used by the Germans for solid tires. It seems to show that the Germans have made sufficient technical progress to overcome the heating difficulties previously arising when synthetic rubber was used for this type of work. The method of adhesion to the metal band was by means of an intermediate layer of hard, probably natural rubber.