(b) Predictor control.—With a predictor control, the data for the first round is calculated in the same way as for an aerial target. Corrections for line, range, and fuze length are made from observation of fire and set on the respective scales on the predictor.
(c) Fire directed from an OP.—When the target is below the horizontal, or at ranges greater than 10,340 yards (that is, beyond the limit of the telescopic sight), fire is directed from an OP. The OP officer takes bearing, range, and elevation from his shooting map. From these he calculates the gun data with a range table and forwards the information to the gun position by telephone. A director is sometimes used for giving the original line to the guns. Corrections are ordered from observation of fire and set at the gun.
(d) Air burst HE.—Fire for effect with time fuze airburst HE against troops in the open and against battery positions has also been reported. Ranging is carried out with a low height of burst. Fire for effect follows with the fuze length adjusted for the most effective height of burst.
(4) Service of the piece.—The 88-mm unit, which is under divisional control for tactical purposes, goes into action from the ammunition line. Here the ammunition trucks are left, and the battery commander, the chief of section, and the driver reconnoiter the assembly point, usually within 225 yards of the gun position, in march order, and the crew prepares it for action when the command is given at the assembly point.
The gun crew is composed of a gun commander and nine men. The service of the gun for antitank fire is divided among them as follows:
Gun commander:
No. 1: Lays for elevation
No. 2: Lays for line
No. 3: Loads and fires
Nos. 4, 5, 6, 7: Handle ammunition
No. 8: Sets range (vertical deflections)
No. 9: Sets lateral deflections
(5) Characteristics.—The German 88-mm dual-purpose gun, which was used in such effective fashion in the desert, was designed primarily as an antiaircraft weapon, but like many German antiaircraft guns, it may also be employed against ground targets as explained. The high muzzle velocity and the resultant striking power of this weapon make it particularly effective against armored targets and fortified gun positions, even at considerable ranges. Using HE and armor-piercing ammunition, it is employed with deadly effect against medium and heavy tanks.
(a) Gun.—The barrel is jacketed, with easily detachable breech rings, a supported, interchangeable A tube (the rifled part of the tube), and a removable guide ring. It is 16 feet long and has 32 rifling grooves. The breech is semiautomatic and self-cocking, opening when the barrel runs out after the shot has been fired, ejecting the cartridge case, and at the same time compressing the striker spring.
(b) Carriage.—The carriage consists of a mounting built into the platform of the chassis, the upper carriage with a protective armor shield, a buffer fitted into the barrel cradle, a hydropneumatic recuperator fitted above the barrel, two balancing springs to distribute the excess weight of the barrel and cradle, and the traversing and elevating mechanism.
(c) Sight.—The standard German antiaircraft sight, modified to give range readings in meters rather than elevation angles, is normally used, but the armor shield also has a loop-hole for the wide-angle (emergency) sight. With the telescopic sight, the line of sights is parallel to the axis of the barrel when both deflection and range drums are set at zero. Since, however, the sight is 28 inches to the right of and 8 inches below the barrel, the aiming point must be taken low and to the right if direct hits are to be obtained.
The elevation field is determined by fixing an attachment on the sextant from -3° to +15°. The traverse field is limited by the striking of the upper carriage against the armor of the driver's seat. The traversing arc is 151° to the right and 181° to the left, or a total traverse of 332°
(d) Mobility.—Two methods are still used to give the gun its well-known mobility: (1) some of the guns are mounted on the special trailer (No. 201) which is fitted with pneumatic tires and drawn by a half-track vehicle which carries the gun crew and a small supply of ammunition. Ground targets can be engaged while the gun is in this traveling position. (2) the newer development is the self-propelled mounting consisting of a 12-ton half-track vehicle, armored in front and carrying a small supply of ammunition. The gun mounted in this position is used only for engaging ground targets.
Rules on the selection of a firing position are as follows: the angle of impact should be not greater than 60°; the range should generally not exceed 2,000 yards; the gun level must slope downward with the wheels nearer the target lower (the gun level varies from -3° to +15° from the horizontal of the muzzle); the position should be concealed and as near to the target as possible to insure maximum accuracy and surprise in opening fire; the lanes of approach and withdrawal must be as firm and level and as wide as possible.
The prime mover can knock down trees up to 3 inches in diameter, and the self-propelled carriage can level 5-inch trees. The minimum widths, which must be considered in choosing lanes of approach and withdrawal, are: with barrel at right angles, 20 feet; with side supports in rest position, 16 feet; and with side supports in march position, 10 feet. If narrow points have to be negotiated on the way to the firing position, the side supports are not put down until these points are passed, nor is the barrel swung free until there is sufficient room. At all times, however, the barrel, with its armored shield, is directed toward the enemy.
(e) Summary.—Following is a list of characteristics of the German 88-mm dual-purpose gun (on towed carriage):
•Muzzle velocity: 2,690 feet per second
•Maximum ordinate: 36,000 feet
•Maximum horizontal range: 16,200 yards
•Effective range against tanks: 3,000 yards
•Effective ceiling: 34,000 feet
•Elevation: -3° to +85°
•Traverse: 360°
•Weight of piece in firing position including outriggers: 11,354 pounds
•Weight of tube: 3,175 pounds
•Caliber: 88-mm
•Length in calibers: 56
•Height of tube over outriggers: 52 inches
•Height of tube over earth: 63 inches
•Longest recoil: 41 inches
•Shortest recoil: 28 inches
•Weight of trailer: 16,426 pounds
•Tread: 70 inches
•Diameter of wheels: 36 inches
•Weight of projectile: 21 pounds
•Weight of propelling charge: 20 pounds
•Weight of bursting charge: 1.5 pounds
•Rate of fire: 15 to 20 rounds per minute
g. 75-mm Sturmgeschütz (Assault Gun)
The Germans have mounted their 75-mm Kw. K.10 (used also as the main armament of the Pz. Kw. IV)11 on the chassis of their Pz. Kw. III. The turret is removed and replaced by a squat superstructure housing the gun. The gun compartment is roofed, but there is no rotating turret. The gun is fitted with a dial, not a telescopic sight. The gun commander has a scissors telescope. Two wireless receivers and one transmitter12 are carried. There is no mounting for a machine gun. The armor is 55 mm (2.17 inches) at the front, 30 mm (1.18 inches) at the sides, and 12 mm (0.47 inches) on top. Inside this moving pillbox, a crew of four are required: the commander (on the left), the driver, gunner, and leader (on the right).
This gun is employed in independent battalions. It is possible that these assault guns have now become organic parts of the motorized and Panzer divisions, as well as part of the front-line infantry divisions. Normally only direct fire is used. It is believed that this low-velocity 75-mm gun is being replaced by a high-velocity 75-mm gun with a reported length of bore of about 43 calibers.
An assault gun of this type captured in the Middle East has been described as follows:
The gun and mount weigh about 20 tons. The gun itself is the short-barreled 75-mm tank gun originally mounted in the Mark IV tank. The range drum is graduated for HE up to 6,550 yards and for AP up
to 1,640 yards. Elevation and traverse are hand-operated. The hull is that of the standard German Mark III tank with normal suspension system. The turret has been removed. The length is 17 feet 9 inches, height 6 feet 5 inches, and width 9 feet 7 inches. In general, the armor is 51 mm (2 inches) at the front and 32 mm (1.25 inches) on the sides and at the rear. An added 53-mm plate is fitted to the rear of the vertical plate, apparently between the driving and fighting compartments, and is braced to the front plate by two 31-mm plates, one on each side of the opening for the gun. The sides of the hull enclosing the driving compartment appear to be vulnerable to the British 40-mm antitank ranges. The engine is a Mayback V-12-type rated at 300 horsepower. The gears provide for six speeds, and steering is hydraulically controlled. The capacity of the gasoline tank is 71 gallons, which is consumed at the rate of about 0.9 miles per gallon at a cruising speed of 22 miles per hour. As in German tanks, this vehicle is equipped to carry extra gasoline in a rack on the rear of the vehicle, which should hold about 10 standard 5-gallon gasoline cans. The captured vehicle contained metal boxes for 44 rounds of ammunition, and 40 rounds were stacked on the floor at the loader's station. Ammunition is also carried in an armored half-track vehicle which tows an armored ammunition trailer. There was also a rack for 12 stick grenades, and the usual smoke-candle release mechanism for 5 candles was fitted to the rear. For communication there were two radio receivers and one transmitter. For observation a scissors telescope was provided. As spare parts the 11-mm sloping plates over the track guard carried two spare bogie wheels on the right side and one on the left side. Two spare torsion rods were also carried, one in each side of the hull above the bogies. Some other details are—
•Length of bore: 23.5 calibers.
•Muzzle velocity (estimated): 1,600 feet per second.
•Elevation: 20°.
•Depression: 5°.
•Traverse: 20°.
•Weight of projectiles: HE, 12 pounds 9 ounces; Smoke, 13 pounds 9 ounces; AP (with ballistic cap), 13 pounds 9 ounces; AP (hollow charge), not known.
•Estimated penetration of AP: 55-mm (2.16 inches) with ballistic cap at 60° at 400 yards.
h. Russian 76.2-mm Gun
It is reliably reported that the Russian 76.2-mm field gun is being used in Libya by the Germans for antitank purposes. Published photographs of this weapon indicate that it is a practical high velocity weapon.
USE OF ENEMY EQUIPMENT
a. General
In the fast moving situation in the desert, where the tide of battle changes quickly, considerable effort has been made to use captured enemy materiel in boomerang fashion. There have been many instances of captured enemy guns being manned by their captors.
The four-gun 75-mm battery captured in Omar Nuovo was manned by the regimental headquarters personnel of one regiment and the lost infantrymen of another division. They fired over a 1,000 rounds back at the Italians and took part in the bombardment of Libyan Omar.
Extensive use was made of captured machine guns, antiaircraft weapons, artillery, tanks, and motor vehicles captured from time to time throughout the operations in Syria. Considerable use was made of captured weapons in the British defense of Tobruk.
b. Use of Captured Italian Weapons
The British have captured large amounts of enemy matériel, particularly Italian. The use of all these captured field artillery weapons has been limited by a lack of spare parts, the recoil systems, both spring and hydro-pneumatic, having suffered particularly. The carriages of the 100-mm and 149-mm howitzers are old models, and the best performance from these weapons can be expected only when they are mounted on modern carriages. None of these weapons is considered suitable for mobile operations in the desert, but they are satisfactory under static conditions. Although some of the Italian weapons have not proved satisfactory enough to be used by the British, some have been used with interchangeable British ammunition and parts and others with Italian ammunition.
AMMUNITION
A direct hit at close ranges from a 105-mm gun or a 25-pounder has usually knocked out the tank or the crew, regardless of the point of impact. High-explosive shells are always useful against personnel in the open and in light shelters. Flashless powder is highly desirable, especially for medium and heavy artillery, which are the favorite targets of dive bombers, strafing fire, and enemy batteries. Weapons have been difficult to detect at a distance when using this type of propellant. The use of separate-loading ammunition places any weapon at a disadvantage during action against armored vehicles.
The Germans give much attention to the effect of the tropical sun on their munitions and weapons. All ammunition other than small arms ammunition is especially packed for the Tropics. All munition cases are so marked. Normal charges for tropical use are calculated at an average temperature of 77° Fahrenheit.
Caissons have been found to be one of the best means of stowing ammunition, because they both protect the ammunition and make it readily available and mobile.
Protection is needed because of the vulnerability of shells and fuzes piled on the ground. The explosion of stacked ammunition set afire by an aircraft cannon wiped out in one instance two Bofors crews. It is true that stacked ammunition can be dug in for protection against shell fire and air attack. However, the mobile operations of the desert give little time for digging protective pits for ammunition—in fact, there is hardly ever sufficient time to dig slit trenches for personnel. Protection at the guns cannot be given by trucks, because they are too conspicuous and vulnerable to be allowed to remain at gun positions as ammunition carriers. Dumped ammunition can seldom if ever be saved in the sudden moves of armored action. Caissons are the British solution to all these difficulties.
The British use artillery trailers between the 25-pounder gun and its prime mover. Two trailers are also coupled behind a prime mover to form the ammunition section. Each trailer can carry 32 rounds of 25-pounder ammunition and fuzes, plus some extra space for a small amount of supplies. These loaded trailers are dropped near the gun positions and give some protection against air attack and shelling, serving the same purpose as horse artillery caissons.
SECTION III. TACTICS
INTRODUCTION
This section on the tactical employment of artillery in the North African campaigns is influenced by two considerations:
a. The Task-Force Principle.
The development of the task-force principle underlines the importance of the coordinated tactical action of all arms. Therefore, while the main focus here is on artillery action, this will always be referred to the general operations in which artillery plays its part.
b. Special Conditions of Desert Warfare.
The terrain and climate of this theater have imposed certain limitations and set certain problems, some of which involve or affect the use of artillery.
RECONNAISSANCE
a. General
Both large and small units operate over wide desert expanses. The lack of cover necessitates great dispersion, which in turn requires each unit to provide its own close-in defense—a situation emphasizing the need of reconnaissance.
Constant use is made of both ground and air reconnaissance units. Even the side which is weaker in air strength carries on air reconnaissance. Forward ground reconnaissance is usually executed by armored cars. Frequently German armored car patrols are supported by tanks, in a ratio of one tank to two armored cars, to provide sufficient fire power to overcome hostile patrols and outposts and thus extend the depth of observation. Once contact is gained by the Germans with an armored force, it is kept under observation even though the German armored units may have withdrawn. As a result, German armored units have been able to avoid battle when conditions were not favorable, to make night attacks against bivouacs, and even to surround hostile bivouacs during the night with antitank weapons and destroy the armored vehicles from close range in the morning.
b. Methods of Observation
Although the desert is not completely flat, suitable
vantage points for observation posts are never very high. This lack of height, together with the heat waves rising from the hot sand and rocks, sometimes reduces visibility in the desert. Mid-day is the least satisfactory period for observing fire.
Both sides endeavor to gain what high ground does exist in the desert. It has been noted that the German infantry in Libya, as elsewhere, have launched attacks for the purpose of obtaining observation posts for their artillery. In one instance such an attack was made to gain ground only 3 feet higher than the surrounding terrain.13 Similarly, German artillery officers have been known to ride on top of tanks in order to gain height for observation.
In both German and British armored divisions the artillery has its own armored vehicles for observation posts. However, even artillery with unarmored troops utilizes methods similar to those of the armored divisions. Forward observers are well out in front with those covering forces, armored cars, or carriers which are deployed for reconnaissance and outpost duty. Often these mobile OP's must be with the armored-car screen, and they are then in an armored car or scout car. Many British officers have spoken highly of the U.S. M-3 Scout Car for this work. Its chief advantage is that it accommodates the entire OP party, whereas the armored car has room for only three persons. Armored cars or scout cars are assigned to and maintained by artillery units. Enough cars must be provided so that all radio sets allotted to a battalion can be mounted in such vehicles; these can then be used by forward observers. The advisability of providing more than a few such cars has been quickly realized, because they wear out soon and have a high casualty rate. Unless the OP is the same type of vehicle as that used by the supported troops, the enemy will concentrate its fire power on the OP vehicle.
German Artillery in Combat Page 12
