The Assault Gun Concept in World War II

Assault guns were a class of armored vehicle unique to Axis forces during World War II. Not to be confused with assault rifles, assault guns resembled a tank without a turret and were used extensively by the Germans, while the Italians and Hungarians emulated the German design on a limited basis. These weapons were built to deliver direct-fire artillery support for infantry assaults, while proving more economical to build and less vulnerable to enemy fire than tanks.

The first tanks of World War I were not built to the pattern that is recognizable today. They were large and slow, and they mounted at least one light artillery gun directly into the hull. Such guns could be rotated to aim at a particular target, but the field of fire remained limited, and additional guns needed to be added if a full 360 degree field of fire was desired. In 1916 and most of 1917, these tanks were used solely as fire support for the infantry, often likened to a mobile pillbox or to an armored artillery battery. The success of the first day of Cambrai showed that tanks could be used as the spearhead of the attack, with infantry serving as the support, but it was the French FT-17 tank that altered the physical design of tanks to this day.

The FT-17 was a light tank that mounted a single small gun (or machine gun) on a turret. Its firepower was therefore much lighter than the behemoths that preceded it, but it could deliver that fire anywhere around it, making it much more efficient than the preceding designs. In a sense, the FT-17 reinvented the wheel, proving on land in 1918 what the USS Monitor proved at sea in 1862: that a smaller number of guns mounted on a rotating turret were more valuable than a larger number of guns arranged in fixed positions. Like the Monitor, the FT-17 inspired widespread imitation, and by the 1930’s, the presence of a turret became a defining characteristic of a tank.

The field of fire afforded by a turret improved the self-sufficiency of the tank, allowing it to better serve as the spearhead of any advance. At the same time, turrets made tanks more expensive to build, and lengthened production time. They could also be a liability: the seam where the turret rests in the hull of the body of the tank was one of the weakest gaps in any tank’s armor, and a direct hit delivered there was often fatal for all inside. These were all concerns with which planners in the German Army wrestled in the 1930’s, when they hastened to rebuild their military capability.

At the time, no army embraced the independent capabilities of the tank more fully than the German Army. Under the influence of men like General Heinz Guderian, the German Panzers were designed to spearhead the rapid offensives that are known today as Blitzkrieg. At the same time, they saw value in providing the regular infantry with some form of armored support, in the manner of early World War I tanks. Because of the expense in time and resources involved in building turreted vehicles, simply building more tanks and delivering some of them to infantry formations was not a desirable option.

A turretless design was simpler and more economical, but it also offered two other distinct advantages: its low profile and lack of a turret seam presented a smaller target for enemy guns, while the decision to mount the gun directly inside the hull allowed the placement of a larger gun. It should be remembered that in the later 1930’s, as the assault gun was being developed, German tanks were strictly light PzKpfw I and II tanks, which mounted guns no larger than 20mm. The medium PzKpfw III and IV tanks that rose to prominence in 1940 were products of the same period of development as the assault gun. Indeed, the original assault gun, the Sturmgeschütz (StuG) III was built upon a turretless PzKpfw III hull and mounted the same gun as the PzKpfw IV, the short-barreled 75mm gun.

The Sturmgeschütz III, upgraded through 1943 with model letters up to G, was both the first and the largest class of assault guns; the very term “assault gun” is a literal translation of the German word Sturmgeschütz. Total production of the various models of StuG III exceeded 9000. The Germans would later build another class of assault gun based on the PzKpfw IV hull, designated the StuG IV, as well as several other models that did not bear the Sturmgeschütz name: the Sturmhaubitze 42, the Brummbär and Sturmtiger. The Italians imitated the concept with their Semovente (which means “self-propelled), while the Hungarians built the Zrinyi. Properly speaking, these are the only assault guns of World War II.

Some sources expand the list to include both Axis and Allied tank destroyers and even self-propelled artillery vehicles. The use of these terms can easily become an exercise in semantics; all are examples of artillery mounted on tracked vehicles that provide some measure of armored protection for their crew. The same, however, could be said of tanks. Tanks have turrets, while the other vehicles do not, requiring the drivers to point their vehicles toward their targets, although most of them have at least a limited traverse ability for their guns. There are, however, notable distinctions among these three categories based on their intended use, despite the eventual crossover that occurs in practice during wartime.

Self-propelled artillery is intended primarily for indirect fire and usually mounts a medium gun. It represents a way to deliver heavier artillery support for a rapid advance, reducing the amount of time involved in limbering artillery for movement to a new site and then setting it up to fire again. It is capable of firing directly, but something has usually gone terribly wrong when that is necessary. Self-propelled guns usually have some sort of protection for the crew under those circumstances, but is usually arranged as a shield covering three sides against small-arms fire, rather than full armor plating.

Tank destroyers look much more like assault guns, and are the product of similar logic, including the opportunities to save expense and weight by giving up a turret. Tank destroyers are configured, first and foremost, to kill enemy tanks while assault guns are configured to deliver all-purpose fire. Tank destroyers carry long-barreled guns for maximum armor penetration. Early assault guns had short-barreled guns, although later models of the StuG III employed medium-length guns to improve their anti-tank performance. In practice, tank destroyers and assault guns could be used interchangeably on the battlefield, and they were often so used. Tank destroyers could deliver devastating fire to infantry formations, while assault guns proved to be excellent tank killers, destroying a reported 20,000 Allied tanks by the spring of 1944 according to German records. It might also be noted, however, that this interchangeability also applies to tanks. During the last year of the war, assault guns and tank destroyers were sometimes delivered to armored units instead of tanks, due to dwindling supplies.

Assault guns were always intended to deliver general-purpose fire in support of other units. The increase in their anti-tank firepower can be attributed to this. As enemy tanks became more powerful, assault guns needed heavier armor-piercing firepower to contend with them. The assault guns were originally used to support infantry, but as the war progressed, they were also employed increasingly to support armored units as well. Either way, enemy tanks were a problem, particularly in the event of a counterattack, and assault guns were meant to deal with them. This was fully a part of their general purpose role, and not a modification of it.

In the German Army, assault guns were organized under the artillery, not under the Panzerwaffe (the department that governed tanks). As with all artillery units, assault gun units were not employed in large formations of their own; rather, companies or battalions were assigned to larger units, which could be infantry or armored formations. Assault guns were assigned missions and objectives by the commanding generals of the larger formation as a part of this service, but logistics were governed by the Artillery Weapons Department, which also set general policies for the assault guns’ use.

Official instructions for the assault artillery component of the artillery department, issued in 1940 and updated in 1942, specifically outline the intended use of the assault gun. During this period, it was always meant to serve alongside the infantry for mutual support. The assault gun provided the primary source of support fire that the infantry needed to carry out an attack or maintain a defense, while the infantry protected the assault gun from a sustained short-range threat, against which the assault gun had no countermeasures. It could also be used to support an armored advance, although its role was seen as secondary in this early period; its primary use under such circumstances was foreseen in neutralizing anti-tank guns, and thereby freeing the tanks to resume their high-speed advance.

Assault guns could be used to provide indirect fire under exceptional circumstances, but this was not their intended role and was not to be undertaken when there were mobile tasks that remained to be performed. Interestingly, assault guns were considered the principal source of fire support, with conventional artillery playing a decidedly secondary role; where possible, the assault gun crews served as official spotters. Standard artillery was mainly used to silence enemy artillery by counterbattery fire; other targets were more efficiently attacked by the assault guns than by indirect fire. In part, this was a product of the German style of Blitzkrieg itself, in which rapid movement did not afford the artillery arm enough time to set up large-scale artillery support. In part, air support replaced artillery in this role, but the Luftwaffe could not wholly replace the artillery. The assault gun was meant to be another contributor to the artillery role in a fast-paced campaign.

The original manual specifically forbade the intentional use of the assault gun to attack tanks. The nature of battle made it happen anyway, and to the surprise of the army, the assault guns proved to be capable tank-killers. The 1942 update lifted the prohibition on anti-tank use, and by 1943, assault guns were being upgraded and reorganized in ways that permitted them to function effectively with limited support. It was not so much that the distinction between assault guns and tank destroyers was erased, as that the distinction between assault guns and tanks was withering. Eventually, Panzergrenadier units received assault guns or tank destroyers instead of tanks, due to the limited numbers of the latter.

While assault guns also served in the Italian and Hungarian armies, they were the invention of the Germans and were shaped by the circumstances of Germany’s rearmament program in the 1930’s and the General Staff’s understandings of the kinds of fighting they would be expected to undertake. The pace of Blitzkrieg required alternatives to conventional field artillery, with tactical bombers and assault guns serving as the primary substitutes. The support role that planners foresaw required a design that was cheaper and faster to build than a normal tank; in the process, they designed a vehicle that could carry heavier armor, especially in front, and still perform all duties assigned to it. Assault guns exceeded their creators’ expectations, and became the most versatile class of armored fighting vehicle in World War II.



Doyle, Hilary et al.  Sturmgeschütz III Assault Gun 1940-42.  Osprey, 1996

Haskew, Michael.  World War II Data Book: The Wehrmacht 1935-45.  Amber, 2011

Ibid.  Weapons of WWII.  Amber, 2012

Perrett, Bryan.  Sturmartillerie and Panzerjäger 1939-45.  Osprey, 1999

Sommerville, Donald.  The Complete Illustrated History of World War II.  Anness, 2009


© 2013.  All rights reserved.