Tactical Employment of German 75-mm Assault Gun, WWII Tactical and Technical Trends, No. 19: February 25, 1943 (Lone Sentry)

The German 75-mm assault gun (7.5-cm Sturmgeschütz) is a weapon comparable to the U.S. 75-mm and 105-mm self-propelled guns. The gun and mount weigh about 20 tons. Its maximum speed cross-country is about 7 mph, on roads about 22 mph; it can average about 15 mph. On normal roads its radius of action is about 100 miles, cross-country about 50 miles. To move an assault-gun battery 100 kilometers (about 65 miles) requires 4,000 liters (about 1,050 gallons) of gasoline. The range of the 75-mm short-barrelled tank gun (7.5-cm KwK), with which this weapon was originally equipped, is about 6,000 yards.

It is reported that there are now apparently three types of assault guns in service. These are: the Stu.G. 7.5-cm K, mounting the 7.5-cm KwK (short-barreled tank gun--23.5 calibers*); the Stu.G. lg. 7.5-cm K, mounting the 7.5-cm KwK 40 (long-barreled tank gun--43 calibers); and a third weapon, nomenclature at present unknown, which appears to have a 75-mm gun with a bore 30 calibers in length. It seems probable, therefore, that the 7.5-cm KwK 40, which is the principal armament of the new Pz. Kw. 4 (Mark IV tank), may be primarily an antitank weapon, while the latest intermediate gun will take the place of the old Stu.G. 7.5-cm K as a close-support weapon.

While some technical details of this weapon have been known for some time, relatively little information has been available until recently concerning its tactical employment. Two German documents on the tactical use of this weapon have now been received. One is dated May 1940, the other April 1942. The second document is essentially identical in substance with the first, except that the second contains some additional information. Both documents have been combined into one for the present report, and such apparent contradictions as exist are noted in the translation which follows.

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INSTRUCTIONS FOR THE EMPLOYMENT OF ASSAULT ARTILLERY

a. Basic Principles and Role

The assault gun (7.5-cm gun on an armored self-propelled mount) is an offensive weapon. It can fire only in the general direction in which the vehicle is pointing** Owing to its cross-country performance and its armor, it is able to follow anywhere its own infantry or armored troops.

Support for the infantry in attack is the chief mission of the assault gun by virtue of its armor, maneuverability, and cross-country performance and of the rapidity with which it can open fire. The moral support which the infantry receives through its presence is important.

It does not fire on the move. In close fighting it is vulnerable because its sides are light and it is open-topped. Besides, it has no facilities for defending itself at close quarters. As it is not in a position to carry out independent reconnaissance and fighting tasks, this weapon must always be supported by infantry.

In support of an infantry attack, the assault gun engages the enemy heavy infantry weapons which cannot be quickly or effectively destroyed by other weapons. In support of a tank attack, it takes over part of the role of the Pz. Kw. 4, and deals with enemy antitank guns appearing on the front. It will only infrequently be employed as divisional artillery, if the tactical and ammunition situation permits. Assault artillery is not to be included in the divisional artillery fire plan, but is to be treated only as supplementary, and to be used for special tasks (e.g., roving batteries). Its employment for its principal tasks must always be assured.

[The April 1942 document states that "The assault gun may be successfully used against armored vehicles, and light and medium tanks." The May 1940 document, however, states "It is not to be used for antitank purposes, and will only engage enemy tanks in self-defense or where the antitank guns cannot successfully deal with them." This apparent contradiction can perhaps be explained by the fact that, prior to the invasion of Russia in 1941, this weapon had been used in limited numbers only. Experience on the Eastern Front may have shown that it could be successfully used against tanks, although Russian sources refer to it as essentially an infantry support weapon. A more logical explanation perhaps lies in two German technical developments since 1940: namely, hollow-charge ammunition, which is designed to achieve good armor-piercing performance at relatively low muzzle velocities, and the reported replacement of the short-barreled low-velocity 75-mm with the long-barreled high-velocity tank gun (7.5-cm KwK 40) on some of the newer models.]

b. Organization of the Assault Artillery Battalion and Its Batteries

The assault gun battalion consists of battalion headquarters and three batteries. The battery has six guns--three platoons, each of two guns.*** The command vehicles for battery and platoon commanders are armored. They make possible, therefore, movement right up to the foremost infantry line to direct the fire.

c. Principles for Employment

(1) General

Assault gun battalions belong to GHQ artillery. For the conduct of certain engagements, battalions or separate batteries are attached to divisions, or to special task forces. The division commander should attach some or all of the assault artillery batteries under his control to infantry or tank units; only in exceptional circumstances will they be put under the artillery commander. Transfer of batteries from support of one unit to another within the division can be carried out very quickly in the course of a battle. Close liaison with the batteries and within the batteries is of primary importance for the timely fulfillment of their missions. The assault artillery fires from positions in open ground, hidden as far as possible from ground and air observation. Only when employed as part of the divisional artillery will these guns fire from covered positions.

Splitting up of assault-gun units into small parts (platoons or single guns) jeopardizes the fire power and facilitates enemy defense. This should occur only in exceptional cases when the entire battalion cannot be employed, i.e., support of special assault troops or employment over terrain which does not permit observation. If employed singly, mutual fire support and mutual assistance in case of breakdowns and over rough country are not possible.

As complete a picture as possible must be obtained of the enemy's armor-piercing weapons and the positions of his mines; hasty employment without sufficient reconnaissance might well jeopardize the attack. Premature deployment must also be avoided. After an engagement, assault guns must not be given security missions, especially at night. They must be withdrawn for refuelling, overhauling, and resupply. After 4 to 5 days in action, they must be thoroughly serviced. If this is not possible, it must be expected that some will not be fit for action and may fall out. When in rear areas, they must be allotted space near repair shops so that they are readily accessible to maintenance facilities, etc.

Troops co-operating with assault guns must give all support possible in dealing with mines and other obstacles. Artillery and heavy infantry weapons must give support by engaging enemy armor-piercing weapons.

Surprise is essential for the successful employment of assault-gun battalions. It is therefore most important for them to move up and into firing positions under cover, and generally to commence fire without warning. Stationary batteries fire on targets which are for the moment most dangerous to the infantry (especially enemy heavy infantry weapons), destroy them, and then withdraw to cover in order to avoid enemy fire. With the allotment of smoke ammunition (23 percent of the total ammunition issue),**** it is possible to lay smoke and to blind enemy weapons which, for example, are sited on the flank. Assault artillery renders support to tanks usually after the hostile position has been broken into. In this role, assault-gun batteries supplement Pz. Kw. 4s, and during the fluid stages of the battle direct their fire against enemy antitank weapons to the direct front. They follow very closely the first waves of tanks. Destruction of enemy antitank weapons on the flanks of an attack will frequently be the task of the Pz. Kw. 4.

Against concrete positions, assault guns should be used to engage casemates with armor-piercing shells. Co-operation with assault engineers using flame-throwers is very effective in these cases.

Assault guns are only to be used in towns and woods in conjunction with particularly strong and close infantry support, unless the visibility and field of fire are so limited as to make use of the guns impossible without endangering friendly troops. Assault guns are not suitable for use in darkness. Their use in snow is also restricted, as they must usually keep to available roads where enemy defense is sure to be met.

(2) Tactical Employment

(a) On the Move

Vehicles on the move should be kept well spaced. Since the average speed of assault guns is about 15 mph, they must be used in leap-frog fashion when operating with an infantry division. Crossing bridges must be the subject of careful handling. Speed must be reduced to less than 5 mph, and the assault guns must keep exactly to the middle of the bridge, with intervals of at least 35 yards. Bridges must be capable of a load of 22 tons. The commander of the assault guns must cooperate with the officer in charge of the bridge.

(1) In the Infantry Division

While on the move, the division commander keeps the assault-gun battalion as long as possible under his own control. According to the situation and the terrain he can, while on the move, place one assault gun battery in each combat team. The attachment of these weapons to the advance guard is exceptional. In general, assault gun batteries are concentrated in the interval between the advance guard and the main body, and are subject to the orders of the column commander.***** On the march, the battery commander and his party should accompany the column commander.

(2) In the Armored Division

On the move, the assault gun battalion attached to an armored division can be used to best advantage if included in the advance guard.

(b) In the Attack with an Infantry Division

The division commander normally attaches assault-gun batteries to the infantry regiments. On receipt of orders placing him under command of an infantry regiment, the battery commander must report in person to the commander of that infantry regiment. Exhaustive discussion between these two (as to enemy situation, preparation of the regiment for the attack, proposed conduct of the attack, main point of the attack, co-operation with divisional artillery, etc.) will provide the basis for the ultimate employment of the assault-gun battery.

It is an error to allot to the battery tasks and targets which can be undertaken by the heavy infantry weapons or the divisional artillery. The battery should rather be employed to engage such nests of resistance as are not known before the beginning of the attack, and which, at the beginning or in the course of the battle, cannot be quickly enough engaged by heavy infantry weapons and artillery. It is the special role of the assault-gun battery to assist the infantry in fighting its way through deep enemy defense zones. Therefore, it must not be committed until the divisional artillery and the heavy infantry weapons can no longer render adequate support.

The attached battery can be employed as follows:

(1) Before the attack begins, it is located so as to be capable of promptly supporting the regiment's main effort; (or)

(2) The battery is held in the rear, and is only committed if, after the attack begins, a clear picture is obtained of the enemy's dispositions.

Under both circumstances the attachment of the battery, and occasionally of individual platoons, to a battalion may be advantageous.

The commander under whose command the battery is placed gives the battery commander his orders. The latter makes clear to his platoon commanders the specific battle tasks, and shows them, as far as possible on the ground, the targets to be engaged. When in action the battery commander, together with his platoon commanders, must at all times be familiar with the hostile situation, and must reconnoiter the ground over which he is to move and attack. The battery will be so disposed by the platoon commanders in the sectors in which it is expected later to operate that, as it approaches the enemy, the battery, under cover, can follow the infantry from sector to sector. How distant an objective can be given, and yet permit the control of fire by the battery and platoon commanders, is dependent on the country, enemy strength, and enemy action. In close country, and when the enemy weapons are well camouflaged, targets cannot be given to the platoons by the battery commander. In these circumstances, fire control falls to the platoon commanders. The platoons must then co-operate constantly with the most advanced infantry platoons; they remain close to the infantry and engage the nearest targets. The question of dividing a platoon arises only if individual guns are allotted to infantry companies or platoons to carry out specific tasks: e.g., for action deep into the enemy's battle position.

In an attack by tanks attached to an infantry division, the assault-artillery battalion engages chiefly enemy antitank weapons. In this case too, the assault-gun battalion is attached to infantry elements. Well before the beginning of the tank attack, the batteries are disposed in positions of observation from which they can readily engage enemy antitank weapons. They follow up the tanks by platoons, and under special conditions--e.g., in unreconnoitered country-- by guns, as soon as possible. In a deep attack, co-operation with tanks leading an infantry attack is possible when the hostile islands of resistance have been disposed of.

In the enemy tank counterattack, our own antitank guns first engage the hostile tanks. The assault-gun battalion engages the enemy heavy weapons which are supporting the enemy tank counterattack. Only when the antitank guns prove insufficient, do assault guns engage enemy tanks. In this case the assault guns advance within effective range of the enemy tanks, halt, and destroy them with antitank shells.

In such an attack, the following tasks can be carried out by the assault gun battalion:

(1) Support of the tank attack by neutralizing enemy antitank weapons; (and/or)

(2) Support of the attack by motorized infantry elements.

According to the situation and the plan of attack, the battalion, complete or in part, is attached to the armored brigade, sometimes with parts attached also to the motorized infantry brigade. Within the armored brigade, further allotment to tank regiments is normally necessary. As a rule, complete batteries are attached.

To support the initial phase of the tank attack, assault-gun batteries can be placed in positions of observation if suitable ground is already in our possession. Otherwise the batteries follow in the attack close behind the first waves of tanks, and as soon as the enemy is engaged, support the tanks by attacking enemy antitank weapons.

As the tank attack progresses, it is most important to put enemy defensive weapons out of action as soon as possible. Close support of the leading tanks is the main essential to the carrying out of these tasks.

The support of the motorized infantry attack is carried out according to the principles for the support of the foot infantry attack.

(d) In the Attack as Divisional Artillery

In the attack of a division, the employment of the assault gun battalion as part of the divisional artillery is exceptional. In this role, the assault-gun batteries must be kept free for their more usual mission at all times, and must enter battle with a full issue of ammunition.

(e) In the Pursuit

In the pursuit, assault-gun batteries should be close to their own infantry in order to break at once any enemy resistance. Very close support of the leading infantry units increases their forward momentum. Temporary allotment of individual platoons--under exceptional circumstances, of individual guns--is possible.

(f) In the Defense

In the defense, the primary task of assault artillery is the support of counterthrusts and counterattacks. The assembly area must be sufficiently far from the friendly battle position to enable the assault-gun units to move speedily to that sector which is threatened with a breakthrough. Allotment and employment are carried out according to the plan of the infantry attack. The point of commitment should be arranged as early as possible with the commanders of the infantry units allocated to the counterthrust or counterattack. In the defense as in the attack, the assault-artillery battalion will only be employed in an antitank role if it must defend itself against a tank attack. (Only 12 percent of the ammunition issue is armor-piercing.)****** If employed as part of the divisional artillery (which is rare), the battalion will be placed under the division artillery commander.

(g) In the Withdrawal

For the support of infantry in withdrawal, batteries, and even individual platoons or guns, are allotted to infantry units. By virtue of their armor, assault guns are able to engage enemy targets even when the infantry has already withdrawn. To assist disengagement from the enemy, tank attacks carried out with limited objectives can be supported by assault guns. Allotment of assault-gun batteries or platoons to rear parties or rear guards is effective.

d. Supplies

As GHQ troops, the battalion takes with it its complete initial issue of ammunition, fuel, and rations. When it is attached to a division, its further supply is handled by the division. The battalion commander is responsible for the correct supply of the battalion and the individual batteries, especially in the pursuit. Every battery, platoon, and gun commander must constantly have in mind the supply situation of his unit. It is his duty to report his needs in sufficient time and with foresight, and to take the necessary action to replenish depleted supplies of ammunition, fuel, and rations.

* Length of bore
** Traverse is limited to 20 degrees
*** The April 1942 document states that a battery has 7 guns, the extra gun being "for the battery commander."
**** According to the April 1942 document, the issue is only 10 percent smoke. It is probable that the ammunition issue depends on the particular operations involved.
***** The April 1942 document states that "an assault gun battery well forward in the advance guard may ensure the rapid crushing of enemy resistance." It does not specify whether this is applicable to operations with infantry or with armored elements.
******* 15 percent according to the April 1942 document.