LHMBC. This action breaks an internal sheet pin and internal wire, thereby disabling the proximity function. He places his thumbs alongside the forefingers, being careful to keep both hands away from the muzzle. Both the 60mm and 120mm mortar rounds use White Phosphorus. An ammunition lot number is assigned to each ammunition lot, which is marked on each cartridge and packing container. M64A1 Sightunit. The cartridge is painted light green with black markings and one narrow brown band. The types of fuzes described in this paragraph are point detonating, proximity, mechanical time, multioption, and dummy. It was even a tool used by airborne units, and was dropped in parachute bundles during Operations Neptune, Market Garden, and Varsity. The fuze wrench, M18, assembles the fuze to the cartridge, and the bladed tip on the end sets PD-type fuzes. Propelling charges are covered or protected from dampness or heat. The safety/packing clip should be removed when the cartridge is unpacked. (2) The breech plug is screwed tightly to the barrel. If you look at the table above, you'll see that at 1.5km range, 120mm mortars have nearly 33% more dispersion than 80mm mortars.Try testing 80mm mortars and 120mm mortars at 1.5km against . a. It is a smooth-bore, muzzle-loading, high-angle-of-fire weapon used for long-range indirect fire support to light infantry, air assault, and airborne units across the entire front of a battalion zone of influence. Safety before firing is provided by a safety wire, which must be removed just before firing. c. The assistant gunner moves into position to the front of the bipod on his right knee and grasps the bipod legs (palms up), lifting until they clear the ground enough to permit lateral movement. a. The M853 cartridge (M252 only) has a cylindrical body that contains an illuminating candle and parachute assembly. If not, he may still fire at the desired range by selecting a charge zone having a higher elevation. Safety before firing is provided by a safety wire, which must be removed just before firing. Mount The propellant train (except the training cartridge) consists of an ignition cartridge and propellant charges. The removable increments are fitted onto or around the shaft, depending on their type. Target terrain, such as ice and dry sand, gives lowest burst heights, whereas water and wet ground give highest burst heights. He indicates the initial direction of fire by pointing in that direction and commands ACTION. After the mortar is mounted, the gunner makes a thorough check. The cartridge weighs about 9.12 pounds. The standard infantry support weapon is the M-252 81mm mortar, which lobs a 10 lb. M327 mortar is an extended range mortar system operated by Marine Corps Artillery Units. It has a time setting of up to 25 seconds. The assistant gunner cleans the bore and swabs it dry. Joint Tables of Allowance; PB - Professional Bulletins; STP - Soldier Training Publications; TC - Training Circulars; . It uses the M185 propelling charge that consists of eight increments fitted into the spaces between the fins and held by a propellant holder. 120MM Mortar System. The gunner moves the mortar as the assistant gunner steadies it. SMALL DEFLECTION AND ELEVATION CHANGES. a. Point-Detonating. These propellants are flash-suppressed and clean burning resulting in minimum residue, flash and blast overpressure. a. It uses the M219 propelling charge and weighs about 9.1 pounds. The powder increments, mainly, should not be exposed to direct sunlight. With the clamps facing away from him, the assistant gunner traverses the buffer carrier to the traversing handwheel and folds the handle. b. At this command, the squad proceeds as follows: a. The American M1 81mm Mortar, like the upcoming M2 60mm Mortar, was based on a French design by Edgar William Brandt (1880-1960). It is especially useful if the baseplate sinks deep into the ground during prolonged firing. The contents of ammunition containers are shown by markings. It has no safety pins or wires to reduce preparation time. (1) The barrel is clean and free from grease and oil both inside and out. The propellant increments are ignited, which produce rapidly expanding gases that force the cartridge from the barrel. Mount, M177, in folded position. The M889 HE cartridge (M252 onlyXUS Marine Corps) is of the same construction as the M821 cartridge in every detail except the fuze, which is the M935. Ammunition is typed according to use (Table 4-2). This ensures that the mortar does not fire should the round slip down the barrel during the subsequent drills. Illuminating is used for battlefield illumination and signaling. It can provide all-weather, ground-based, close supporting, accurate, immediately .50 MACHINE GUN, M3; FIRING CARTRIDGE, CAL. The squad leader stands behind the mortar where he can command and control his squad. f. Installation. He moves the mortar until the vertical line of the sight is aligned approximately on the aiming post. The 0-second boss is wider and differs in shape from the other body bosses; the safe setting position is indicated by the letter "S" on the fuze body. The gunner is given an administrative command to lay the mortar on a deflection of 2860 or 2740 mils. a. He then checks the sight picture to ensure he is within 20 mils of a proper sight picture. 0.30, BROWNING, M1917A1; GUN, MACHINE: CAL. (4) The bipod locking latch is locked, securing the barrel clamps. The gunner places the outer edge of the baseplate against the baseplate stake so that the left edge of the cutaway portion of the baseplate is aligned with the right edge of the stake (Figure 4-7). Cartridges assembled with the M524 (A1, A2, A3, or A4) fuze are for use by the US Marine Corps and US Navy only. From introduction up to halfway World War 2 the ML 3-inch had a poor range of up to 1.45 km. In any case, the gunner must ensure that the cartridge does not strike an obstacle. Cartridges assembled with the M532 fuze must be fired above charge 0. All elements given in the fire command are repeated by the squad. c. The first ammunition bearer checks the barrel and ensures that--. c. The assistant gunner disengages the barrel clamps and moves the bipod from the immediate area of the mortar position. An official website of the United States government. e. The pull wire and safety wire are removed from the fuze just before firing. These fuzes use a clockwork mechanism to delay functioning for a specific time. (3) The M256-series fuze has an SQ/IMP function only. 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. Training practice--M879, M880, M68, and sabot. Overhead interference can be branches of trees or roofs of buildings. Both legs are fitted with a disk-shaped foot with a spike beneath to prevent the mount from slipping. (See FM 7-90 for a discussion of the duties of the platoon headquarters.). d. The first ammunition bearer stands to the right rear of the mortar. The fuze arms and functions normally when fired at any angle of elevation between 0800 and 1406 mils at charges 1 through 9. The M301A3 cartridge has a cylindrical body that contains an illuminating candle and parachute assembly. The vertical cross line of the sight is on the left edge of the aiming point. The company level vehicles also carry a vehicle-mounted 120mm mortar, which is augmented by the 60mm M224 mortar for dismounted use. This section discusses the characteristics and nomenclature of each component (Figure 4-2). d. Multioption. (8) To help minimize the occurrence of short rounds and or duds, unpackaged ammunition that has been dropped should not be fired. The gunner levels the elevation bubble by turning the elevation micrometer knob and reading the setting on the elevation scale and elevation micrometer--this setting is the minimum mask clearance. Fired . Then he relocks the barrel clamp. XM1210. The fuze consists of a brass head, body assembly, and expelling charge. To dismount the mortar, the squad leader commands, OUT OF ACTION. b. Finally, the assistant gunner loosens the leg-locking handwheel, presses the spring-loaded locating catch, and raises the plain leg behind the buffer cylinders until it touches the traversing handwheel. They are fuzed with the M524-series, M256-series, or M532. MORTAR RANGE: 500M X 100M X: FIELD TRAINING AREA 40000 Sq Ft: X STORAGE BUILDING, GENERAL PURPOSE, INSTALLATION: Area to store excess equipment X: ORGANIZATIONAL STORAGE BUILDING Arms room for Mortar equipment: X . They are painted light green with red markings and one narrow yellow band. ), 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). (4) Extra increments are removed if the cartridge is to be fired with less than full charge. He exposes 4 inches (100 millimeters) of elevation shaft and folds the handle. The floating firing pin located within the primer has approximately 1/16 of an inch to move around. A proximity fuze is an electronic device that detonates a projectile by means of radio waves sent out from a small radio set in the nose of the projectile. The M252 81mm medium extended range mortar (see diagram below) is a crew-served, smooth bore, muzzle loaded, high angle of fire weapon system. With the mortar mounted and the sight installed, the gunner lays the sight on the 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 cartridge is dropped down the barrel, fin-end first. c. Crest Clearance. To set for delay, the selector slot should be rotated clockwise until it is aligned with the "D" mark on the ogive. The baseplate (Figure 4-5) is of one-piece construction, and supports and aligns the mortar for firing. Cartridges assembled with the M524 (A1, A2, A3, or A4) fuze are for use by the U.S. Marine Corps and U.S. Navy only. He places firing data on the sight and lays the mortar for deflection and elevation. The M374A2 and M374A1 cartridges are fitted with the M90A1 propelling charge. At the muzzle end is a cone-shaped blast attenuator device (BAD) that is fitted to reduce noise. However, at temperatures above 32 degrees Fahrenheit and at angles greater than 1068 mils, the flight time is sufficient to permit arming. The second ammunition bearer retrieves the aiming posts. The assistant gunner carries the bipod to the front of the barrel and places the bipod feet on the ground 12 to 15 inches in front of the baseplate and astride the line of fire. 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. The entire squad stays with the mortar. 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. Check the post SOP before applying the following procedure: (1) Select a place at least 100 meters from the mortar position, parked vehicles, and ammunition piles. 81mm 120mm 60mm . Referring and realigning aiming posts ensure that all mortars are set on the same data. The gunner stands to the left side of the mortar where he can manipulate the sight, elevating handwheel, and traversing handwheel. Excess increments should not accumulate near the mortar positions but are removed to a designated place of burning and destroyed. TM - Technical Manuals (Range 9) TM - Technical Manuals (Range 10) TM - Technical Manuals (Range 11-4) TM - Technical Manuals (Range 11-5) . It is set using the bladed end of the M18 fuze wrench. This section contains information on how to prepare the 81-mm mortar, M252, for firing, how to conduct safety checks, and, if a misfire should occur during firing, what actions the crew applies to remove the cartridge from the barrel. c. The M375A2, M375A1, and M375 cartridges may also be used. Additional information is included on an ammunition data card inside each container. He exposes 1 inch (25 millimeters) of cross-level shaft and folds the handle. Prev - Mk6 Mortar range table for charge 0 Next - Mk6 Mortar range table for charge 2 . It is fitted with a safety wire and pin that are removed immediately before firing. It is painted white with black markings. He rotates the socket so that the open end is pointing in the direction of fire. (3) The M84A1 fuze is a single-purpose, tungsten-ring, mechanical-time fuze used with the 81-mm M301A3 illumination cartridge. A plain leg is fitted to a stud on the elevating leg and is secured by a leg-locking handwheel. The M532 fuze is a radio doppler fuze that has a proximity (PROX) or SQ/IMP function. It has a time setting of up to 50 seconds. Maximum Range (meters): 7,240 (with standard fuze) . 107 Army Pentagon Lock b. 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. The cartridge is painted olive drab with yellow markings. The mortar should be within two turns of center of traverse when the task is compete. To prepare for firing, the slot is aligned in the striker with SQ or delay using the M18 fuze wrench. Designed by Thingsym. 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. Army Publishing Directorate All PD fuzes are superquick--detonate on impact. It comes preset to function on SQ/IMP, and the selector slot should align with the SQ mark on the ogive. However, since explosives are affected by moisture and high temperature, they must be protected. That is generally how I use mortars. 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 . He uses the chain of command to assist him in effecting his command and supervising duties. I say 120s are bad because they suffer from terrible dispersion even when not shooting at 6km. He is also the squad driver. Each squad member should be able to perform all the following premount checks: a. a. M252 81mm Mortars The M252 81mm medium extended range mortar (see diagram below) is a crew-served, smooth bore, muzzle loaded, high angle of fire weapon system. If the line of sight clears the mask, it is safe to fire. Correct way to open an ammunition box. The M751 is fitted with a smoke charge that operates on impact. Increments removed from cartridges before firing should be placed in a metal or wooden container located outside the firing vehicle/position at least 25 meters away. The BAD is removed only by qualified maintenance personnel. Developed by Hirtenberger Defence Systems (HDS), the rugged and reliable M8 comprises an 81 mm long-range weapon available in different barrel lengths, an entire range of ammunition, auxiliary field equipment, sighting systems and a fully digital fire-control system containing all ballistic data.