Despite the German disagreement with the modification made in their Panzer I tanks, it wasundoubted that the tank’s combat capacity was greatly improved thanks to the Italian 20mm Breda Mod.35 gun.The Breda Mod.35 was really a dual purpose gun with limited anti-tank capability. With armour piercing ammunition it could penetrate 30mm of armour from 500 meters away.The inicial forecast was to transform 6 Panzer I installing the Breda gun. Unfortunately, after the German opposition to this arrangement, the works were cancelled and only 4 tanks were finally transformed.After installation of Breda Mod.35 gun in the Spanish Panzer I, other Italian vehicles were later equipped with this weapon. Among them are the Fiat AB-41 armoured car and the Fiat L6/40 light tank, which indicates the success of such modification by the Spanish military.
The enhanced Panzer I with Breda Mod.35 gun were able to penetrate 40mm of armour at 250 meters maximum distance, which was enough to defeat the Republican T-26B. Nonetheless, due to the small number of upgunned tanks, they hardly influenced the course of the fighting.
