Inch Chemical Mortar

Department of the Army. Transfer of the Responsibilities for the 4.2-inch Chemical Mortar and Related Equipment to the Ordnance Department. Washington, DC HQ, DA 9 Feb 1948. Memorandum. 

Bottom photos of ordnance typically found in old munitions ranges Left top to bottom 3.5-inch rocket 2.5-inch bazooka. Right top to bottom 81-mm illumination mortar 3-inch Stokes chemical mortar 60-mm high explosive mortar. 

In this particular instance Major Wilson was probably right. But, in retrospect, this incident and the supply operations which it represents assume more significance than the immediate problems imply, for this operation marks the bifurcation of the chemical supply system. Henceforth, one element of the chemical supply system was oriented, despite doctrine to the contrary, to an impetus from the front. This element of the system was primarily devoted to meeting the demands and special requirements of the combat forces, especially for new equipment, such as the lightweight mechanical smoke generator, or equipment used in new missions, such as the 4.2-inch chemical mortar. ... 

As the combat period approached, Colonel Unmacht and his stafiF turned their attention from numerous projects in gas warfare defense and decontamination to the nontoxic chemical weapons and munitions. Their work on the flame thrower tank, and later on stabilized flame thrower fuels, was the outstanding overseas development work of the worldwide CWS. Unmacht was a strong proponent of the use of the 4.2-inch chemical mortar with high-explosive shell, and the development, testing, and combat supply of a landing craft mortar mounting for Pacific amphibious operations represented one of his achievements in the field of combat support. The mortar gun boat development was also a noteworthy example of Army-Navy co-operation. 

The CWS stored some ammunition, smoke agents, and toxic agents, about eleven tons of FS smoke, 3,000 HC smoke pots, and nearly 500 tons of bulk toxics almost evenly divided between persistent and non-persistent gases. The departmental ordnance officers stored some toxic and smoke-filled ammunition. The departmental CWS carefully hoarded 32 4.2-inch chemical mortars, aware that the whole Army had only 44. ... 

On lo July 1943 American, British, and Canadian forces landed on the southern and eastern coasts of Sicily, and in the ensuing 3 8-day campaign the 4.2-inch chemical mortar met its first test in combat. This CWS weapon, still untried in battle nineteen months after the entry of the United States into the war, by 1945 was to become an important part of the Army s arsenal. 

The 4.2-inch mortar was the culmination of attempts to improve the 4-inch British Stokes Brandt (SB) mortar. With American-made SB mortars and with shell and propellants purchased from the British after World War I, the CWS sought to obtain increased range, accuracy, and mobility. By 1924, experiments under the direction of Capt. Lewis M. McBride (later colonel) produced the rifled 4.2-inch chemical mortar with a range of over 2,000 yards, and by the end of World War II this distance had been doubled. ... 

Chemical Mortars, 4-inch and 4.2-inch, in Summary of Activities of the Mechanical Division, Edge wood Arsenal, 1920-1928 (hereafter cited as ATR 1S9) Proj 8a 29 May 33, p. 63. 

Inch Chemical Mortar Crew in Action during the Italian campaign. 

Inch Mortar in World War II, pt. II, The Italian Campaign, p. 53 This is a detailed study of chemical mortar operations in Italy. 

Fighting in Italy was as bitter and the enemy defenses as stubborn as any experienced by American forces in World War II. The mountainous Italian terrain, with its abundance of defiladed positions inaccessible to artillery fire, placed a heavy demand on high trajectory weapons, particularly the 4.2-inch mortar. In addition, 4.2-inch mortar units were indispensable to Ranger and Commando units which lacked organic heavy weapons. Most infantry commanders were at first unaware of the potential of the 4.2-inch mortar, but once they had seen the weapon in action they were usually anxious for mortar support. In Italy the chemical mortar truly came of age. 

The initial combat employment of chemical mortar units in the war against Japan took place in September 1943 during the fight for New Georgia in the South Pacific Area. It must be re-emphasized that the CWS did not receive authorization for the high explosive mission for 4.2-inch mortars until 19 March 1943, nearly seven months... 

Field artillery officers were impressed by the amount of effective fire produced by a chemical mortar company as compared to that of an artillery unit. Maj. John D. Tolman, who commanded the 8zd Chemical Mortar Battalion from 26 April until the close of the Luzon Campaign, disclosed that infantry commanders felt they could not "properly accomplish [their] mission [without] 4.2-inch mortar sup-... 

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