The Semovente da 75/18 was an Italian self-propelled gun of the Second World War. It was built by mounting the 75mm Obice da 75/18 modello 34 mountain gun on the chassis of an M13/40, M14/41 or M15/42 tank. The first 60 were built using the M13/40 chassis and a subsequent 162 were built on the M14/41 chassis from 1941 to 1943, when the M15/42 chassis was introduced. The Semovente da 75/18 had been intended to be an interim vehicle until the heavier P40 tank could be available.
This self-propelled gun was built with riveted steel plates and a crew of three – driver, loader/radio operator, and tank commander/gunner. The main gun was a derivative of a 75mm L/18 gun, itself a quite modern divisional artillery piece. The gun had a muzzle brake, and there were several observation and aiming systems (binoculars, periscopes and others) for the crew. Only one roof-mounted machine gun was fitted for close defence, though sometimes it was omitted. Initially this was a 6.5 mm Breda but was later upgraded to an 8mm model. A Radio model RF1 CA with interphone was usually fitted.
Even though the Semovente da 75/18 was technically similar to the StuG III, it had a totally different role, serving as divisional artillery instead of a pure assault gun. The SPGs were deployed in the North African campaign and during the Allied invasion of Sicily, alongside medium tank units to provide additional firepower. Despite the fact that they were not designed to fight other tanks, their 75mm howitzer proved ideal (thanks to its low muzzle velocity) for firing HEAT shells; its 5.2kg HEAT shell ('Effetto Pronto' in Italian) could pierce 80mm of armour at 500m, and could thus defeat tanks such as the US-built M3 Grant and M4 Sherman used by the British Army. As such, these machines were responsible for many of the successes by the Italian armoured troops during 1942–43, when the medium tanks (all armed with a 47mm gun) were no longer effective. A total of 262 units were built.
After the Italian surrender in 1943, some 131 Semovente da 75/18 were seized by the Germans and the production of another 55 was authorized. All units were intended for service in Italy or the Balkans and designated as StuG M42 mit 7,5 KwK L 18(850)(i).