Along with millions of people, WWI killed old war tactics. In the most cruel war to date, the best engineers in the world created new weapons, for a new war. One of the questions that had to be addressed was the relationship between artillery and infantry.
When advancing, infantry takes heavy losses. They need artillery to crush the enemy's defenses. Towed guns cannot keep up, as they are not mobile enough. WWI saw the first self propelled guns: cannons on tractor chassis, in trucks, or on tracks, moved by electrical actuators. The agility of the latter kind was questionable, but good enough for the war that was being fought.
In 1935, Erich von Manstein sent a memo to General Beck, describing the necessity of creating self propelled guns, protected by armour, and capable of knocking out enemy hardpoints. These guns should also be capable of dealing with enemy tanks. These guns were not meant to fight alone, or in mass formations, but in platoons. This memo was the start of a new type of mechanized forces: assault guns.
There was no consensus about what to do with this idea. Opposition (including Heinz Guderian) insisted that tanks can support infantry just fine. The German PzIV tank had a gun just for that purpose. Unlike an SPG, it had a turret, allowing it to shoot in all directions. After considering all pros and cons, the Germans high command decided to develop an armoured vehicle for infantry support. The vehicle was the responsibility of Daimler-Benz, and Krupp was going to make the 75 mm gun.
In July of 1937, five experimental vehicles left the factories. They had a modified PzIII chassis, with a 75 mm gun in a closed, low profile casemate. There were no machine guns on this first iteration. The vehicle had a low profile and good armour, but a poor engine, allowing it to only reach 25 kph. However, that was enough at the time.
The first vehicles were not meant for combat use. The hulls were made from mild steel. After tests at Kummersdorf, these vehicles were transferred to an artillery school, where they were used until 1941.
In 1940, after several modifications, Daimler-Benz released the first batch of new vehicles. These tanks had a new engine, 50 mm of front armour, and an improved suspension. They were named "7.5 cm Sturmgeschutz III Ausf A", or StuG III for short. In just over a month, these tanks would fight in France. At the end of the campaign, they received the highest of praises from their commanders and crews.
Convinced of the StuG's effectiveness, the Wehrmacht ordered to move the production from DB's overloaded factories to Alkett. Production was increased to 30 vehicles per month. In 1940, 184 StuGs were produced, and 584 in 1941.
The StuG III became the most numerous assault gun in WWII. 10 500 were produced. Aside from being very effective in combat, the StuG was also cheaper than the PzIII, let alone the PzIV. The PzIII cost around 105 000 marks, while the StuG cost only 82 500.
In 1942, the StuG got a new long barreled 75 mm gun. This modification turned an effective assault gun into an effective tank destroyer. The StuG became the main anti-tank weapon of the German army, surrendering the role of infantry support to the StuH 42, developed on the same chassis with a more powerful howitzer.
Like all German tanks released over a long period of time, the StuG underwent many modifications and modernizations in order to increase its combat effectiveness. Eight revisions of the StuG III were manufactured.
As the Germans faced more and more perfected vehicles, the StuG was improved in turn. The short barreled 75 mm gun was ineffective against T-34s, let alone KV-1 and KV-2s. This was the cause of the aforementioned gun upgrade. Later, an even more powerful gun was needed.
Along with new main guns, the StuG also got a machine gun. The StuG's enemy was not always a tank, and an infantry escort was not always available. The assault gun was extremely vulnerable to infantry in close quarters. Starting with Ausf E, the StuG had a machine gun on the roof, protected by an armoured shield. It had a limited traverse, but it was better than nothing. The Ausf F had a remote controlled machine gun that could rotate fully, which saved the lives of many German tankers.
Some of the StuG's modernizations had unfortunate side effects. While trying to make the vehicle as protected as possible, German engineers increased the thickness of the armour and added anti-HEAT screens, increasing the mass of the vehicle and making it slower and more sluggish.
The biography of the StuG has many glorious pages. Near Stalingrad, Kurt Pfrendtner's StuG destroyed 9 tanks in 20 minutes. In the battles for Demyansk, Horst Naumann's crew destroyed 12 vehicles in 3 days. The most famous StuG ace was Walther Knipp. From July 1943 to January 1944, his division destroyed 129 Soviet tanks. Finnish aces Berie Brotel and Erkki Halonen also fought in StuGs.
After the end of WWII, the StuG remained in the Romanian, Spanish, Egyptian, and Syrian armies, further proving the effectiveness of this fantastic vehicle.
Original article available here.