The bazooka is a man-portable anti-armor rocket launcher, made famous during World War II. It was one of the primary infantry anti-tank weapons used by the United States Armed Forces, and was based on the principle of the High explosive anti-tank (HEAT) shell. It was nicknamed "bazooka" from a vague resemblance to the musical instrument of the same name invented and used by Bob Burns. The M1A1, M9, and M9A1 rocket launchers saw widespread use throughout WWII.
The word "Bazooka" is often informally used to refer to any shoulder-launched missile weapon.
The development of the bazooka involved the development of two specific lines of technology: the rocket-powered (recoilless) weapon, and the shaped-charge warhead.
The Rocket-Powered Recoilless Weapon was the brainchild of Dr. Robert H. Goddard as a side project of his work on rocket propulsion. Goddard, during his tenure at Worcester Polytechnic Institute, Clark University, and at Mount Wilson Observatory, designed a tube-fired rocket for military use during World War I. He successfully demonstrated his rocket to the US Army Signal Corps at Aberdeen Proving Ground, Maryland, on November 6, 1918, but as the Armistice was signed only five days later, further development was discontinued. Goddard continued to be a part-time consultant to the US Government at Indian Head, Maryland, until 1923, but soon turned his focus to other projects involving rocket propulsion.
The development of the explosive shaped charge dates back to the work of American physicist Charles Edward Munroe, who did the first practical work on the subject in 1880. This work was augmented in the 1930s by Henry Mohaupt, a Swiss immigrant who worked on shaped-charge explosives design for the War Department (the predecessor of the Department of Defense).
Mohaupt developed a shaped-charge hand grenade for anti-tank use that was effective at defeating up to 60 mm (2.4 in) of armor, by far the best such weapon in the world at the time. The grenade was standardized as the M10. However, the M10 grenade weighed 3.5 lb (1.6 kg), was difficult to throw by hand, and too heavy to be launched as a rifle grenade. The only practical way to use the weapon was for an infantryman to place it directly on the tank, an unlikely scenario in most combat situations. A smaller, less powerful version of the M10, the M9, was then developed, which could be fired from a rifle. This resulted in the creation of a series of rifle grenade launchers, the M1 (Springfield M-1903), M2 (Enfield M-1917), and the M7 and M8 for the M1 Rifle. However, a truly capable anti-tank weapon had yet to be found, and following the lead of other countries at the time, the U.S. Army prepared to evaluate competing designs for a large and powerful anti-tank rifle.
In 1940, U.S. Army Lieutenant Edward G. Uhl, under the command of Colonel Leslie A. Skinner, suggested utilizing the M10 shaped-charge grenade as a warhead attached to a booster rocket, to be fired by an experimental rocket launcher he had recently developed. Development of the M1 prototype took place in Corcoran Hall at The George Washington University in Washington, D.C.. The M1 consisted of a sheet metal tube with a simple wooden stock, handgrips, and sights (replaced by metal in production models), into which the 60.07 mm-diameter (officially designated 'M6, 2.36-inch' to avoid confusion with rounds for the 60 mm mortar) rocket grenades were inserted at the rear. A two-cell dry battery in the wood shoulder rest provided a charge to ignite the rocket when the trigger was pulled. Although the weapon had some reliability and accuracy problems, Ordnance officials were greatly pleased with the penetrative effect of the new M1, which blew the turret off a tank during field trials. The weapon's M6 rocket warhead was capable of penetrating roughly 4 inches (100 mm) of armor plate. As a result, the War Department cancelled all plans for anti-tank rifles and in 1942 adopted the M1 rocket launcher and its M6 rocket as standard. The M1 rocket launcher was the first type to see combat use.
By late 1942, the Rocket Launcher, M1A1 was introduced. The forward handgrip was deleted, and the design simplified. The production M1A1 was 54 inches (1.37 m) long and weighed only 12.75 pounds (5.8 kg).
The ammunition for the original M1 launcher was the M6, which had a notorious reputation for unreliability. The M6 was improved and designated M6A1, and the new ammunition was issued with the improved M1A1 launcher.
The original M1A1 launcher was equipped with a simple hinged rear sight and fixed front sights, and used a launch tube without reinforcements. During the war, the M1A1 received a number of running modifications. The battery specification was changed to a larger, standard battery cell size, resulting in complaints of batteries getting stuck in the wood shoulder rest (the compartment was later reamed out to accommodate the larger cells). This was followed by a new aperture rear sight and a front rectangular "frame" sight positioned at the muzzle. The vertical sides of the frame sight were inscribed with graduations of 100, 200, and 300 yards. On later models, the iron sights were at first replaced by a plastic optical ring sight, which proved unsatisfactory in service, frequently turning opaque after a few days' exposure to sunlight. Later iron sights were hinged to fold against the tube when not in use, and were protected by a cover. The launcher also had an adjustable range scale that provided graduations from 50 to 700 yards (46 to 640 meters) in 50-yard (46 m) increments. An additional strap iron shoulder brace was fitted to the launcher, along with various types of blast deflectors.
In 1943, field reports of rockets sticking and prematurely detonating in M1A1 launch tubes were received by Army Ordnance at Ogden Arsenal and other production facilities. At the U.S. Army's Aberdeen Testing Grounds, various metal collars and wire wrapping were used on the sheet metal launch tube in an effort to reinforce it. However, reports of premature detonation continued until the development of bore slug test gauges to ensure that the rocket did not catch inside the launch tube.
The original M6 and M6A1 rockets used in the M1 and M1A1 launchers had a pointed nose, which was found to cause deflection from the target at low impact angles. In late 1943, another 2.36-in rocket type was adopted, the M6A3, for use with the newly standardized M9 rocket launcher. The M6A3 was 19.4 inches (49.28 cm) long, and weighed 3.38 lb (1.53 kg). It had a blunted nose to improve target effect at low angles, and a new circular fin assembly to improve flight stability. The M6A3 was capable of penetrating five inches (125 mm) of armor plate.
Battery problems in the early bazookas eventually resulted in replacement of the battery-powered ignition system with a magneto operated through the trigger. A trigger safety was incorporated into the design that isolated the magneto, preventing misfires that could occur when the trigger was released and the stored charge prematurely fired the rocket. The final major change was the division of the launch tube into two discrete sections, with bayonet-joint attachments. This was done to make the weapon more convenient to carry, particularly for use by airborne forces. The final two-piece launcher was standardized as the M9A1. However, the long list of incorporated modifications increased the launcher's tube length to 61 inches (1.55 m), with an overall empty weight of 14.3 lb (6.5 kg). From its original conception as a relatively light, handy, and disposable weapon, the final M9A1 launcher had become a heavy, clumsy, and relatively complex piece of equipment.
In October 1944, after receiving reports of inadequate combat effect of the M1A1 and M9 launchers and their M6A1 rockets, and after examining captured examples of the German 8.8 cm RPzB 43 and RPzB 54 Panzerschreck, the U.S. Ordnance Corps began development on a new, more powerful anti-tank rocket launcher, the 3.5-inch M20. However, the weapon's design was not completed until after the end of the war.
Supplied with the highly unreliable M6 rocket, the M1 did not play a significant role in combat in the North African fighting. A US general visiting the Tunisian front in 1943 after the close of combat operations could not find any soldiers who could report that the weapon had actually stopped an enemy tank. Further issue of the bazooka was suspended in May 1943.
During the Allied invasion of Sicily, small numbers of the M1A1 bazooka (using an improved rocket, the M6A1) were used in combat by US forces. The M1A1 accounted for four medium German tanks and a heavy Tiger I, the latter knocked out by a fortunate hit through the driver's vision slot. A major disadvantage to the bazooka was the large backblast and smoke trail, which gave away the position of the shooter. Moreover, the bazooka fire team often had to expose their bodies in order to obtain a clear field of fire against an armored target. Casualties among bazooka team members were extremely high during the war, and assignment to such duty in the face of German counterfire was typically regarded by other platoon members as not only highly dangerous, but nearly suicidal.
In late 1942, numbers of early-production American M1 bazookas were captured by German troops from Russian forces who had been given quantities of the bazooka under Lend-Lease. The Germans promptly copied the weapon, and increased the diameter of its warhead to 8.8 mm. In German service, the bazooka was popularly known as the Panzerschreck. The German weapon, with its larger, more powerful warhead, had significantly greater armor penetration; ironically, calls for a larger-diameter warhead had also been raised by some ordnance officers during U.S. trials of the M1, but were rejected. After participating in an armor penetration test involving a German Panther tank using both the RPzB 54 Panzerschreck and the US M9 bazooka, Corporal Donald E. Lewis of the U.S. Army informed his superiors that the Panzerschreck was "far superior to the American bazooka...I was so favorably impressed [by the Panzershreck] I was ready to take after the Krauts with their own weapon.
Despite the introduction of the M9 bazooka with its more powerful rocket - the M6A3 - in late 1943, reports of the weapon's effectiveness against enemy armor decreased alarmingly in the latter stages of World War II, as new German tanks with thicker and better-designed cast armor plate were introduced. This development forced bazooka operators to target less well-protected areas of the vehicle, such as the tracks, bogey wheels, or rear engine compartment. In a letter dated May 20, 1944, Gen. George S. Patton stated to a colleague that "the purpose of the bazooka is not to hunt tanks offensively, but to be used as a last resort in keeping tanks from overrunning infantry. To insure this, the range should be held to around 30 yards. In the Pacific campaign, as in North Africa, the original bazookas sent to combat often had reliability issues. The battery-operated firing circuit was easily damaged during rough handling, and the rocket motors often failed because of high temperatures and exposure to moisture, salt air, or humidity. With the introduction of the M1A1 and its more reliable rocket ammunition, the bazooka was effective against some fixed Japanese infantry emplacements such as small concrete bunkers and pill boxes. Against coconut and sand emplacements, the weapon was not always effective, as these softer structures proved too resilient, often absorbing the warhead's impact sufficiently to prevent detonation of the explosive charge. Later in the Pacific war, most infantry and marine units often used the M2 flamethrower to overcome such obstacles. In the few instances in the Pacific where the bazooka was used against tanks and armored vehicles, the rocket's warhead easily penetrated the thin armor plate used by the Japanese, destroying the vehicle.
Overall, the M1A1, M9, and M9A1 rocket launchers were viewed as useful and effective weapons during World War II, though they had been primarily employed against enemy emplacements and fixed fortifications, not as anti-tank weapons. General Dwight Eisenhower later described it as one of the four "Tools of Victory"(together with the atom bomb, jeep and the C-47 Skytrain transport aircraft) one of the four weapons which won World War II for the allies.
During the initial stages of the Korean War, reports again surfaced over the ineffectiveness of the 2.36-in M9 and M9A1 against enemy armor. In one notable incident, infantry blocking forces of the U.S. Army's Task Force Smith were overrun by 33 North Korean T-34 tanks despite repeatedly firing 2.36-in rockets into the rear engine compartments of the vehicles. Supplies of 3.5-in M20 launchers with M28A2 HEAT rocket ammunition were hurriedly airlifted from the United States to South Korea, where they proved very effective against the T-34 and other Soviet heavy tanks.