h. Where the ground is uneven and there is no level surface for the bipod, the gunner can adjust the plain leg. The fuze is set manually to proximity, point detonate, or delay modes. ), FIRING TABLES FOR, CANNON, 155MM, HOWITZER, M185 ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, 109A1 HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, 109A1B HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A2 HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A3 HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A3B AND HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, 109A4 AND CANNON, 155MM, HOWITZER, M284 ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, 109A5 AND HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, 109A6 AND CANNON, 155MM, HOWITZER, M199 ON HOWITZER, MEDIUM, TOWED, 155MM, M198 AND CANNON, 155MM, HOWITZER, XM776 ON HOWITZER, MEDIUM, TOWED, 155MM, XM777 FIRING PROJECTILE, HE, M795 (S&I BY PROP SEE DETAILS, FOOTNOTES), FIRING TABLES FOR CANNON, 155MM HOWITZER, M284 ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A5, M109A6 AND M109A7 AND CANNON, 155MM HOWITZER, M284A2 CHROME ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A6 AND M109A7 AND CANNON, 155MM HOWITZER, M199 ON HOWITZER, MEDIUM, TOWED, 155MM, M198 AND CANNON, 155MM HOWITZER, M776 ON HOWITZER, MEDIUM, TOWED, 155MM, M777, M777A1 AND M777A2 AND CANNON, 155MM HOWITZER, M776 CHROME ON HOWITZER, MEDIUM, TOWED, 155MM, M777A2 FIRING PROJECTILE, SMOKE, WP, M1121 INCLUDES FIRING TABLES FOR PROPELLANTS: M119A2 (CHARGE 7R), M203A1 (CHARGE 8S), AND MODULAR ARTILLERY CHARGE SYSTEM (MACS) PROPELLANTS: M231 (CHARGES 1L AND 2L), M232 AND M232A1 (CHARGES 3H, 4H AND 5H) (S&I BY PROP SEE FOOTNOTES). The wrench (P/N 9349539) sets M772 MT and M768 time fuzes. c. After the gunner has announced, "Up," the squad leader should check the mortar to determine if the exercise was performed correctly. The assistant gunner cleans the bore and swabs it dry. It can be set from 3 to 55 seconds at half-second intervals. The ignition cartridge has a percussion primer and is assembled to the end of the fin assembly. It should be destroyed in accordance with standard procedures. 4-12. When targets are beyond such irregularities, a clearance of at least 30 meters should be allowed to ensure maximum effect over the target area. The following are authorized (Standard B) cartridges for the 81-mm mortar, M252: Each cartridge has fins around the tail to stabilize it in flight and to cause it to strike fuze-end first. The mortar also offered the promised increase in range as well, allowing fire teams to engage the enemy at distance. The lower clamp is shaped and bored on each side to house the buffer cylinders. An M18 fuze wrench is used to change settings. The M29 would become the standard American mortar in the upcoming Vietnam War. The squad leader indicates the direction of fire when mounting. The assistant gunner attempts to maintain the traversing mechanism on a horizontal plane. The gunner stands to the left side of the mortar where he can manipulate the sight, elevating handwheel, and traversing handwheel. Tabulated data. c. The first ammunition bearer checks the barrel and ensures that--. The American M1 81mm Mortar, like the upcoming M2 60mm Mortar, was based on a French design by Edgar William Brandt (1880-1960). b. Safety before firing is provided by a safety wire, which must be removed just before firing. (1) The barrel is clean and free from grease and oil both inside and out. It can provide all-weather, ground-based, close supporting, accurate, immediately See Chapter 3, paragraph 3-14 for a detailed discussion of malfunctions. The M821 HE cartridge (M252 only) is a British-made cartridge fitted with the US M734 multioption fuze. M64A1 Sightunit. It was even a tool used by airborne units, and was dropped in parachute bundles during Operations Neptune, Market Garden, and Varsity. Correct way to open an ammunition box. d. When the barrel reaches the horizontal position, and not before, the assistant gunner moves the thumb of each hand over the muzzle. b. To prepare for firing, the slot is aligned in the striker with SQ or delay using the M18 fuze wrench. The bipod provides front support for the barrel and carries the gears necessary to lay the mortar. All mortar cartridges are painted to prevent rust and to identify their type. He places the sight case and aiming posts to the left front of the mortar position. Propelling charges are covered or protected from dampness or heat. The terms cannon and barrel are used interchangeably in this chapter. The cartridge weighs about 9.4 pounds. Features: The M252 81mm Medium Extended Range Mortar is a crew-served, medium weight mortar which is highly accurate and provides for a greater range (4,500 meters to 5,650 meters) and lethality than the previous 81mm mortar. Proximity fuzes withstand normal handling without danger of detonation or damage when in their original packing containers or when assembled to projectiles in their packing containers. Bear in mind that these are my personal opinions, experiences, and . He performs other duties as the squad leader directs. Share sensitive information only on official, secure websites. The upper clamp is fitted with a locking arrangement that consists of a curved handle and a spring-loaded locking rod, which is ball-shaped at its lower end. The squad leader picks up the sight case and the two aiming posts, and moves to the exact position where the mortar is to be mounted. It uses the M185 propelling charge that consists of eight increments fitted into the spaces between the fins and held by a propellant holder. If the situation allows for a longer waiting period, the dud can be considered safe for handling after 40 hours. The RSTA squadron only receives the 120mm mounted mortar, there is no augmentation dismounted maneuvers. Table 4-1. Dropping may cause the propellant charges to ignite, causing bodily injuries. The components of the mortar consist of a cannon, mount, and baseplate. The baseplate (Figure 4-5) is of one-piece construction, and supports and aligns the mortar for firing. The first ammunition bearer puts both hands on the cooling fins under the barrel and slowly lifts the barrel until it is horizontal. d. The M374A2, M374A1, and M374 HE cartridges are painted olive drab with yellow markings and are constructed from pearlitic malleable cast iron. If not, he may still fire at the desired range by selecting a charge zone having a higher elevation. Those cartridges assembled with the M524 (A1, A2, A3, or A4) fuze are for use by the US Marine Corps and US Navy only. A securing strap is attached to the plain leg for securing the bipod in the folded position. f. Installation. The M853 and M301A3 illuminating ammunition are described herein. M120/M121 120 mm Mortar. It can be fitted with either the M567, M524, or M532-series fuzes. The barrel clamp, which consists of an upper and lower clamp, is situated at the top. M3A1 Baseplate It has two types: type 1 resembles the M734 fuze, and type 2 resembles the M935 fuze. Proximity (VT). The aluminum tail assembly has six integral fins equally spaced around the rear, which stabilize the round in flight. The powder increments, mainly, should not be exposed to direct sunlight. The body is made of aluminum and brass. CANNON . The gunner is given a deflection change between 5 and 25 mils, either increasing or decreasing from the last stated deflection, and the command to refer and realign aiming posts. The M1 became the standard American . These cartridges are used first in subsequent firing so that once-opened stocks can be kept to a minimum. The sight is laid on two aiming posts (placed out 50 and 100 meters from the mortar) on a referred deflection of 2800 mils and an elevation of 1100 mils. The fuze should already be fitted to the cartridge. There is a selector on the lower shaft for non-delay or delay impact action. The assistant gunner checks the bipod and ensures that--. The 81-mm mortar, M252, is a smooth-bore, muzzle-loaded, high-angle-of-fire weapon. More uniform firing is obtained if ammunition is kept at the same temperature. .50: BROWNING, M2 (HEAVY BARREL, TURRET TYPE) ON MOUNT, MACHINE GUN, TRAILER MTD: MULTIPLE CAL. Mount Target terrain, such as ice and dry sand, gives lowest burst heights, whereas water and wet ground give highest burst heights. He tightens the leg-locking handwheel (ensuring the teeth are correctly meshed) and fastens the securing strap over the arm and around the buffers. For those of you in the market for a Dummy/Display 81mm mortar, I hope this article can answer a few of your questions before you order. The cartridge is painted light green with black markings and one narrow brown band. c. The moisture-resistant seal of the container is broken when the ammunition is to be used. Fuzes are not disassembled. a. Before-firing checks include the following: (1) Ammunition should be free of moisture, rust, and dirt. After the rounds have been removed, they should always be handled with two hands to prevent accidental dropping. Then it is removed from the bipod and laid horizontally on the ground at the dud pit until it can be turned over to ordnance personnel. 107 Army Pentagon (2) The M524-series fuze has two function settings: superquick/impact (SQ/IMP) and delay. Their firing positions and principal duties are as follows: a. Following the arm-and-hand signals of the gunner (who is looking through the sight unit), he moves the far aiming post so that the gunner obtains an aligned sight picture. Standard A ammunition for the M29A1 mortar is Standard B for the M252 mortar (, Light green Yellow band with red markings. Mortar Weapon Systems - USAASC The M821A2/821A1/889A1 consists of the following major components: M935 Point Detonating Fuze or M734/734A1 Multi-Option Fuze. 81 mm HE mortar projectiles generally contain anywhere between 400 g and 680 g of HE and have a maximum range of approximately 6,500 m. 82 mm HE mortar projectiles generally contain anywhere between 392 g and 680 g of HE and have maximum ranges of between 3,000 - 5,500 m. b. They are fuzed with the M524-series, M256-series, or M532. d. The squad leader supervises the squad drill and is responsible for supervising the laying out of the equipment as shown in Figure 4-6. The obturating ring ensures equal muzzle velocities in hot or cold barrels by keeping all the gases in the barrel until the cartridge has fired. If the mortar section is to operate quickly and effectively in accomplishing its mission, mortar squad members must be proficient in individually assigned duties. Despite its weight though, the 81mm mortar was an important part of the Table of Organization and Equipment of U.S. Army and U.S. Marine Corps maneuver battalions throughout World War II. a. The mortar is within two turns of center of traverse. The pile is covered with a double thickness of tarpaulin. Additional information is included on an ammunition data card inside each container. If he is not within 20 mils, the gunner and assistant gunner must make another large shift before moving on. Close approach to crests, trees, towers, large buildings, parked aircraft, mechanized equipment, and similar irregularities causes functioning at heights greater than average level. FM 23-90 Chptr 4 81-mm Mortar, M252 - GlobalSecurity.org It arms within a maximum of 2.50 seconds. Illuminating is used for battlefield illumination and signaling. (2) The M84 fuze is a single-purpose, powder-train, mechanical-time fuze used with the 81-mm M301A1 and M301A2 illuminating cartridges. Each cartridge weighs about 10 pounds and is provided with the M223 propelling charge, consisting of four horseshoe-shaped increments fitted around the tail. The mortar is then re-laid on the aiming posts using the traversing crank. PDF Principles of Fire Support B2c0289xq Student Handout The mount consists of elevating and traversing mechanisms and a bipod (Figure 4-4). 120MM Mortar System. News. The Mark 4 and 5 barrels were introduced during World War 2 and have a much increased range. If the round fires, the mortar is re-laid on the aiming point and firing is continued. At the muzzle end is a cone-shaped blast attenuator device (BAD) that is fitted to reduce noise. The fuze arms and functions normally when fired at any angle of elevation between 0800 and 1406 mils at charges 1 through 9. If required, the gunner/assistant gunner lowers the barrel so that the breech plug engages with the open end of the socket, and he uses the barrel as a lever to move the socket. 81MM SYSTEM | Hirtenberger Defense Systems If the primer of the ignition cartridge is dented, the first ammunition bearer attempts to replace the safety wire and places the round in a marked, safe location for disposal by ordnance personnel. b. The squad leader points to the exact spot where the mortar is to be mounted. The squad leader stands behind the mortar where he can command and control his squad. The contents of ammunition containers are shown by markings. It contains white phosphorus that produces white smoke on contact with air. The removable increments are fitted onto or around the shaft, depending on their type. e. Dummy. The second ammunition bearer retrieves the aiming posts. High explosive is used for both fragmentation and blast effect against personnel and light-skinned vehicles. b. c. Mechanical Time. 1:4 For the 81MM Mortar System: X NSN (LIN): 1015-01-441-3113 : STAFF SECTION, CLEANING, ARTILLERY 1:4: c. The assistant gunner lifts the bipod and stands it on its elevating leg so that the elevating handwheel is to the rear and the plain leg is to the front. REFERRING OF THE SIGHT AND REALIGNMENT OF AIMING POSTS USING M64 SIGHT. The fuze wrench, M18, assembles the fuze to the cartridge, and the bladed tip on the end sets PD-type fuzes. He maintains the ammunition for firing and provides local security for the mortar position. d. Multioption. The cartridge uses the M205 propelling charge and is assembled with the M567 or M524-series fuze. The gunner moves the mortar as the assistant gunner steadies it. e. The squad leader picks up the aiming posts and sight. .50 MACHINE GUN, M3; FIRING CARTRIDGE, CAL.

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