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| Japanese Explosive Ordnance – Army Ammunition – Navy Ammunition |
| Chapter 4 – Section 3 |
| ARMY MORTARS |
| 70-mm High-Explosove-Antiaircraft Barrage Mortar |
| Weight complete round: 5.19 pounds. |
| Weight main charge (H.E. cylinders): 12.84 grams. |
| Explosive components: |
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Main charge: RDX. |
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Booster: Lead azide. |
| Over-all length of shell: 11.38 inches. |
| Maximum diameter of shell: 2.76 inches (70 mm). |
| Length of canisters: 6.5 inches. |
| Diameter of canisters: 0.75 inch. |
| Length of H.E. cylinders: 3.12 inches. |
| Diameter of H.E. cylinders: 0.69 inches. |
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Color: Shell, black over-all with a 5/8 inch red band at nose. Conisters, zinc coated (grey). |
| H.E. cylinders: Black over-all with a 3/16 inch ed band at forward end. |
| Weapon in which used: 70-mm A.A. barrage mortar. |
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Description: This mortar shell consists of an outer shell containing seven canisters in each of which is an H.E. cylinder and parachute. A turned steel base is welded to the outer shell, and provision is made for reception of a delay train holder, a shell propellant container, and an end cover. The delay train leads to a black-powder charge which ejects the canisters from the shell. The end cover is fitted over the propellant container and is sealed against moisture and held in position by adhesive type. A wooden plug in a pressed steel cap closes the forward end of the shell. |
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The canisters contain a wooden plug in the base bored to receive a delay element and a small black powder charge to eject the H.E. cylinder from the container. The steel H.E. cylinders are closed at the base and threaded at the forward end to receive a plug into which is screwed a friction cap. The explosive content is in three blocks, each wrapped in a waterproof paper carton. |
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Parachutes are attached to the outer shell, nose cap, and each of the seven canisters and H.E. cylinders. The length of the parachute cords varies from 19 inches (canisters) to 66 inches (cylinders). The H.E. cylinder parachute lines are attached to a friction cord which passes through the friction cap. Thus, this shell, when fired, puts sixteen separate objects suspended by parachutes in the way of low-flying aircraft, seven of which will explode if hit. |
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Operation: The delay train to the first ejection charge is ignitted by the shell propellant charge, and the first charge in turn ignites the delay trains to the second ejection char-ges in each of the canisters. The parachute attached to the nose cap, outer shell, and canisters all open when the canisters are ejected and the H.E. cylinder parachutes open when they are ejected from the canisters. A plane hitting the parachute cord of any of the H.E. cylinders would cause the friction wire to be pulled through the friction cap ini-tiating the explosive train. |
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Figure 302 – 70-mm High-Explosive Antiaircraft Barrage Mortar. |
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