The 43M Zrinyi tracked assault gun was of Hungarian origin and designed from their Turan Medium Tank family during World War 2. Hungary had joined the Axis powers in 1940 and its military would go on to participate in the ensuing large-scale land invasions of both Yugoslavia and the Soviet Union in 1941. The Hungarians, now fully embroiled in world war, were not blind to the successes of the German assault guns, these armored vehicles having been built from modified, obsolete Panzer tank hulls, finding new battlefield value as self-propelled gun systems. Following the disastrous results of Hungarian armor at the hands of Soviet medium and heavy tanks, Hungarian authorities looked to similar assault gun-based developments all their own.
Selecting the Turan Medium Tank as a starting point, the basic hull, chassis, engine and running gear were kept in place. The most noticeable departure was the removal of the turret and armament. In its place, a fixed superstructure was hurriedly added. This design element presented a stout, accurate gunnery platform and was cheaper and quicker to produce than comparable tank systems utilizing full traversing turrets. Conversely, the entire tank would have to turn in the desired direction of fire as traverse was inherently limited by the fixed superstructure - thus proving something of a tactical limitation in-the-field. However, such vehicles could mount larger-caliber guns and would be going into battle alongside adaptable combat tanks so the limitation was negligible.
From the outset, the Hungarian Army required two versions of the assault gun concept. The first version was to field a long-barreled 76mm anti-tank gun (based on the German PaK 40) as its primary armament and act as a dedicated "tank killer". The second version was to be armed with a 105mm field howitzer for use in the infantry support role. The 76mm-armed version was designated as the "Zrinyi I" with the 105mm-armed version becoming the "Zrinyi II". Hungarian warplanners were highly optimistic in the type's successes and planned for a total of eight complete assault battalions, each numbering some 30 Zrinyi assault guns, in support of existing armored and infantry groups.
To accommodate the intended weaponry, the hull of the Turan tank was widened somewhat. Development of the Zrinyi I began to lag behind that of the Zrinyi II, which had already mounted its main gun and was field tested into January of 1943. It was then accepted for serial production as the "43M Zrinyi 105" to begin immediately. The Zrinyi I, however, did not see a prototype completed until late 1943. At which point, the type was tested and accepted for service with serial production set begin sometime in mid-1944 as the "44M Zrinyi I". However, the Soviet occupation of Hungary brought the Zrinyi initiative to a halt, yielding just 60 Zrinyi II examples and only prototype forms of the Zrinyi I. Thus ended the tenure of the Hungarian indigenous assault gun. Only one Zrinyi II form survives today, this at the Kubinka Tank museum outside of Moscow.
The Zrinyi was crewed by four personnel made up of the driver, commander, gunner and loader. Her operating weight was listed at 19,600kg to 21,600kg with a running length of 5.68 meters, a width of 2.99 meters and a height of 2.33 meters. Beyond the main armament, the vehicle would have been defensed by a single 8mm Danuvia 34/40 machine gun. Armor thickness was 13mm to 75mm. The engine was a Manfred Weisz V8 water-cooled gasoline fueled powerplant of 260 horsepower. Range was 220 kilometers with a 43 kilometer top road speed. The engine was mated to a transmission system yielding six forward and six reverse speeds.
The Zrinyi name stemmed from the Hungarian hero Nikolaus Graf Zrinyi, killed in combat against Turk forces in 1566.