Semovente DA 75/18 and Semovente DA 75/34
This series was a continuation of the successful Italian Semovente M40 and M41. The Sturmgeschutz M42 was developed early in 1943 on the basis of the Pz Kpfw M15/42 chassis for the 75/34 gun, but as this weapon was still under test in March 1943, the M42 was fitted with the short 75/18, and 200 such vehicles were ordered. Satisfactory trials with the 75/34 led to a further order for 500 equipped with the long gun. Many of those built for the Italian Army were confiscated for immediate use by the German Army in September 1943. At the Ansaldo Factory, material was available to build many more of each series, and the Germans continued production at a somewhat slower rate.
The same chassis and power plant as for the M15/42 tank. The short 75/18 had already equipped previous, Italian Semovente. On the M42 chassis, the suspension bogies were spaced further apart, and grills were fitted in the forward engine-cover hatches.
Semovente DA 105/25
In 1942, the Italian Army considered mounting a 10.5cm gun on the chassis of their proposed medium tank P40. Delays to the P40, caused an alternative chassis, and based on the M15/42 tank, to be ordered. To accommodate the 10.5cm, this chassis had to be widened and, therefore, became known as M43. In February 1943, 30 units were ordered, in April, a further 100 and by June, a total of 454 had been ordered. Only 26 of the first order fell into German hands, but material existed to manufacture many more, and German records indicate that it was intended to fit 80 with the 7.5cm 75/34 gun. On 5 October 1943, the Germans ordered sixty 105/25. Later, more were ordered and some of these were fitted with additional spaced armour on the superstructure front and sides.
The Semovente 105/25 was the best Italian vehicle at the time of the German occupation, and the Germans ordered production to continue using the material already earmarked for the large Italian orders. By December 1943, tests had been carried out which indicated that the Sturmgeschutz M43 could be improved without loss of performance by the addition of spaced armour. Additionally, it was decided that the Italian 75/46 anti-aircraft gun was to be modified to have the characteristics and ammunition of the German PaK40. After the initial production of sixty 105/25 and eighty 75/34 on the M43, all these were to be rebuilt with the heavier armour and the 75/46 gun. However, production proceeded at a slower rate, because of the difficulties created by the Occupation, and additional M43 were fitted with the heavier armour and the 105/25, while a small number appeared with the 75/34 and the remainder were produced with the 75/46. Italian sources indicate that the total production of M43 in 1945 was 22. It was also intended to rebuild all StuG M42 with the 75/18, and later those with the 75/34, and to fit the 75/46 gun. The shorter superstructure of the M42 was to be modified, and a muzzle brake was to be added to the gun.