The M 15-42 was the final Italian medium tank of the Second World War, but was only just entering service at the Italian Armistice in September 1943. The M 15-42 was developed as a stop-gap measure while work continued on the P 40 heavy tank. It was largely based on the M 14-41, but with a number of key improvements. It was given a 190hp petrol engine in place of the 145hp diesel engine of the M 14, increasing its top speed from 20mph up to 25mph and generally improving performance. The Ansaldo 47/32 gun of the M 14 was replaced with a longer barrelled 47mm Ansaldo 47/40 which had a higher muzzle speed, flatter trajectory and longer range.
The hull was lengthened to accommodate the new engine. The superstructure had thicker armour. The engine deck was modified with vents added and armoured shrouds for the exhaust pipes. The turret was given electro and hydro-dynamic traverse systems.
The M 15-42 was developed during 1942, but very few were produced before the Italian armistice of September 1943. Sources vary in the exact numbers built. Somewhere between 190 and 220 tanks were completed before the armistice and possibly another 287 tanks after the armistice, although some or all of these might have been completed as self-propelled guns. In September 1943 forty five M 15-52s had been issued to the 135th Ariete II Armoured Division and were based near Rome.
The same hull was used to build the Semovente da 105/25 M 43, the best Italian self-propelled gun of the war.
The M 15-42 was also produced as a command tank, the Carro Commando da M 15-42. This had the turret removed and a 13.2mm Breda Model 31 machine gun mounted in the forward hull. It carried extra radio equipment. Some were taken over by the Germans and remained in use in northern Italy to the end of the war.
Weight: 15 tons/ 33,069lb
Armament: 47mm Ansaldo L/40 gun and 8mm machine gun in turret, two 8mm machine guns in hull front
Engine: 195hp Fiat SPA 15 TB eight-cylinder liquid cooled inline petrol engine
Top Speed: 25mph
Length: 16ft 4.8in
Width: 7ft 2.6in
Height: 7ft 10.5in