Mortars are indirect-fire weapon systems. 9301 Chapek Road., Bldg.1458 The firing pin must be replaced and the bore swabbed. Examples are: d. The ammunition is protected from mud, sand, dirt, and water. They are assembled with either an M524-series, M526-series, or M567 fuze. The cartridge must not be fired below charge 3. The cartridge can be fitted with the M524-series, M526-series, M567, or M532 fuzes. It can provide all-weather, ground-based, close supporting, accurate, immediately The M375A3 cartridge is ballistically similar to the M374A3 (HE) cartridge. c. After the gunner has announced, "Up," the squad leader should check the mortar to determine if the exercise was performed correctly. In addition to supervising the emplacement, laying, and firing of the mortar, he supervises all other squad activities. (2) The barrel is locked to the baseplate, and the open end of the socket points in the direction of fire. If the situation allows for a longer waiting period, the dud can be considered safe for handling after 40 hours. With standard mortar, the maximum effective range is close to 4,000 metres; with a long-range system, this increases to nearly 4,500 metres. Weights (pounds) System (including basic issue items) Barrel (with blast attenuator device) Mount M3A1 Baseplate d. Climatic Effects. Theme by TechDoc. b. The American M1 81mm Mortar, like the upcoming M2 60mm Mortar, was based on a French design by Edgar William Brandt (1880-1960). It contains white phosphorus that produces white smoke on contact with air. 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. Attached to the arm is the cross-leveling mechanism, which is attached to the clamp assembly at its upper end. They contain about 2.10 pounds of composition B explosive. The explosive elements in primers and fuzes are sensitive to shock and high temperature. 4-4. SQUAD AND SECTION ORGANIZATION AND DUTIES, Each member of the infantry mortar squad has principle duties and responsibilities. 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. The gunner removes the sight and places it in the case with 3200 deflection and 0800 elevation indexed. 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. Cartridges assembled with the M532 fuze must be fired above charge 0. The mortar should be within two turns of center of traverse when the task is compete. The BAD is removed only by qualified maintenance personnel. The fuze body is graduated from 0 to 25 seconds in 1-second intervals; 5-second intervals are indicated by bosses. Table 4-3. 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. The cartridge is dropped down the barrel, fin-end first. a. Before-firing checks include the following: (1) Ammunition should be free of moisture, rust, and dirt. The principal factors affecting height of burst are the angle of approach to the target and the reflectivity of the target terrain. If it is necessary to leave the ammunition uncovered, it should be raised on dunnage at least 6 inches above the ground. At this command, the squad proceeds as follows: a. He must not stand directly behind the mortar. Short cartridges can be expected when firing below charge 4. It is fitted with a safety wire and pin that are removed immediately before firing. (4) The M567 fuze is an impact fuze that has a SQ/IMP or D function. MC Medical Guide; Client-side mods; TFAR 1.x for players; When set at delay, the fuze train causes a 0.05-second delay before functioning. Do not burn increments in piles but spread them in a train 1 to 2 inches deep, 4 to 6 inches wide, and as long as necessary. d. The gunner rough levels the cross-level bubble by making the bubble bounce from one side to the other. The adjustment ring has six raised ribs for use in conjunction with fuze setter, M25, and a setting indicator rib (marked SET) about half the height and width of the other six ribs. At extreme temperatures (below -40 degrees Fahrenheit and above 125 degrees Fahrenheit), it is not unusual to experience an increase in malfunctions proportionate to the severity of conditions. It uses the M219 propelling charge and weighs about 9.1 pounds. The tabulated data of the 81-mm mortar, M252, are shown in Table 4-1. The M1 became the standard American . Range Minimum to maximum 83 to 5,608 meters Rate of Fire . The M252 system . He knocks down the near aiming post and proceeds to the far aiming post. The increments are individually wrapped with waterproof bags that are not removed. 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. Proximity (VT). It is set using the bladed end of the M18 fuze wrench. When the fuze of the misfired round reaches the BAD, the assistant gunner stops the round with his thumbs (he does not touch the fuze) and carefully removes it from the barrel. c. The elevating shaft is contained in the elevating leg; to the left of the elevating leg is the elevating handwheel. The air burst over average types of soil ranges from 1 to 6 meters, depending on the angle of approach. The powder increments, mainly, should not be exposed to direct sunlight. End this starting train with not less than 1 meter of inert material (dry grass, leaves, or newspapers). 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. These propellants are flash-suppressed and clean burning resulting in minimum residue, flash and blast overpressure. (703) 614-3727, Office of the Chief Information Officer There is a selector on the lower shaft for non-delay or delay impact action. c. The assistant gunner stands to the right of the mortar, facing the barrel and ready to load. The fuze is nicely marked and is dated 1940. Those cartridges assembled with the M524 (A1, A2, A3, or A4) fuze are for use by the US Marine Corps and US Navy only. . If not, he may still fire at the desired range by selecting a charge zone having a higher elevation. b. He places firing data on the sight and lays the mortar for deflection and elevation. These fuzes use a clockwork mechanism to delay functioning for a specific time. Table 4-2. These cartridges are used first in subsequent firing so that once-opened stocks can be kept to a minimum. 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. They function normally in light rain; however, heavy rain, sleet, or snow can cause an increase in the number of early bursts. 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. An 81 mm mortar is a medium-weight mortar. To dismount the mortar, the squad leader commands, OUT OF ACTION. When a misfire occurs, any member of the squad immediately announces, "Misfire." Additional information is included on an ammunition data card inside each container. The first ammunition bearer puts both hands on the cooling fins under the barrel and slowly lifts the barrel until it is horizontal. Long Range PGK. 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. He maintains the ammunition for firing and provides local security for the mortar position. The M821/M889 are 81mm HE Mortar Cartridges. The fuze arms and functions normally when fired at any angle of elevation between 0800 and 1406 mils at charges 1 through 9. c. The M375A2, M375A1, and M375 cartridges may also be used. It weighs about 9.05 pounds. It has no safety pins or wires to reduce preparation time. 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. DESCRIPTION. 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 . See Chapter 3, paragraph 3-14 for a detailed discussion of malfunctions. Close approach to crests, trees, towers, large buildings, parked aircraft, mechanized equipment, and similar irregularities causes functioning at heights greater than average level. The barrel is then rotated a quarter turn to unlock it from the socket, and it is placed in an area designated by the squad leader. At the muzzle end is a cone-shaped blast attenuator device (BAD) that is fitted to reduce noise. (2) The fin and fuze assembly must be checked for tightness and damage. The pile is covered with a double thickness of tarpaulin. (7) When opening an ammunition box, the ammunition bearer ensures the box is horizontal to the ground, not nose- or fin-end up. 4-11. Secure .mil websites use HTTPS Then he relocks the barrel clamp. The superior flow characteristics of these BALL POWDER . I have included my order history, detailed photos, as well as my personal opinion on International Military Antiques, IMA -USA www.ima-usa.com 81mm Display Mortar that they have for sale. 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 vertical cross line of the sight is on the left edge of the aiming point. Table 4-1. The fuze consists of a brass head, body assembly, and expelling charge. Several types of HE ammunition are used in the 81-mm mortar, M252. The M252 81 mm medium weight mortar is a British-designed 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. The fuze is screwed into the cartridge body, and it is seated and secured using an M18 wrench. In charge was the platoon commander - normally a lieutenant. (4) The bipod locking latch is locked, securing the barrel clamps. Light tree foliage and light vegetation affect the height of burst only slightly, but dense tree foliage and dense vegetation increase the height of burst. a. Point-Detonating. It uses the M205 propelling charge, consisting of four horseshoe-shaped increments fitted around the tail. The cartridge is painted light green and has red markings and one narrow yellow band. Disposal Precautions. It should be destroyed in accordance with standard procedures. CANNON . 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. This is the inert PD fuze type "IR-81" used by the Italians for their 81mm mortar rounds during WWII. b. If the round fires, the mortar is re-laid on the aiming point and firing is continued. If not, the cartridge is placed on its side, and the closing plug is removed using an M18 fuze wrench. It has a time setting of up to 50 seconds. 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. He exposes 4 inches (100 millimeters) of elevation shaft and folds the handle. 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. This document (FT 81 B3, abridged) consists of two pages, each with a separate table. The gunner should expose 6 inches (150 millimeters) of elevation shaft and center the buffer carrier. a. Cartridges are shipped with a complete propelling charge, an ignition cartridge, and primer. The gunner is given a deflection and elevation change in a fire command causing the gunner to shift the mortar between 200 and 300 mils for deflection and between 100 and 200 for elevation. The M751 is fitted with a smoke charge that operates on impact. . (2) The breech plug is screwed tightly to the barrel. Powered by Hugo. The components of the mortar consist of a cannon, mount, and baseplate. They are fuzed with the M524-series, M256-series, or M532. Training practice is used only for training. e. The M362A1 and M362 HE cartridges are of steel forge construction and contain about 2.10 pounds of composition B explosive. (1) The rotating socket is free to move in a complete circle. The squad leader notifies the FDC of the minimum mask clearance elevation. The gunner is given a deflection change in a fire command between 20 and 60 mils inclusive. (1) The M772A1 fuze is a MTSQ. It is designed to be fired in the indirect fire mode, cannot be fired handheld, and normally utilizes a FDC. The table on the right describes the three most common setups. More uniform firing is obtained if ammunition is kept at the same temperature. 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. The M853 cartridge (M252 only) has a cylindrical body that contains an illuminating candle and parachute assembly. Each squad member should be able to perform all the following premount checks: a. The same procedure for aligning the far aiming post is used to align the near aiming post. (4) The blast attentuator device is secured correctly. The cartridges are painted olive drab with yellow markings. VERY NICE condition! 60MM M224A1. Both legs are fitted with a disk-shaped foot with a spike beneath to prevent the mount from slipping. They should not be approached for 5 minutes or disturbed for at least 30 minutes after firing. The cartridge weighs about 9.12 pounds. (4) Extra increments are removed if the cartridge is to be fired with less than full charge. c. Mechanical Time. The mortar is within two turns of center of traverse. The fuze contains a delayed arming feature that ensures the fuze remains unarmed and detonator safe for a minimum of 1.25 seconds of flight. It is light enough to be portable when broken down into. Tabulated data. To convert the fuze from PROX to SQ/IMP, the top of the fuze must be rotated 120 degrees (one-third turn) in either direction. a. 60mm, 81mm, and 120mmMortar Increments. The gunner stands to the left side of the mortar where he can manipulate the sight, elevating handwheel, and traversing handwheel. ), 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). After the rounds have been removed, they should always be handled with two hands to prevent accidental dropping. At the same time, the first ammunition bearer moves out on the double to realign the aiming posts. He places his thumbs alongside the forefingers, being careful to keep both hands away from the muzzle. Short cartridges can be expected when firing below charge 4. The elevation change announced must be less than 90 mils and more than 35 mils. All PD fuzes are superquick--detonate on impact. b. The fuze consists of a brass head, body assembly, and expelling charge. The assistant gunner cleans the bore and swabs it dry. The 81-mm mortar, M252, is a smooth-bore, muzzle-loaded, high-angle-of-fire weapon. (2) The ribs and braces have no breaks, cracks, or dents. The cartridge is painted light green with black markings and one narrow brown band. (2) Color code. The M252 81 mm medium weight mortar is a British designed 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. g. The barrel clamps can be moved along the barrel to counter large changes in elevation. The M301A3 cartridge has a cylindrical body that contains an illuminating candle and parachute assembly. An ammunition lot number is assigned to each ammunition lot, which is marked on each cartridge and packing container. CANNON, 155MM HOWITZER, M185 ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A1 HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A1B HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A2 HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A3 HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A3B HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A4 AND 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, HE, M795 PROJECTILE, HE, M795 IM PROJECTILE, HE, M1122 PROJECTILE, IR ILLUMINATING, M1123 PROJECTILE, ILLUMINATING, M1124 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 DETAILS, FOOTNOTES) . While the assistant gunner supports the barrel, the gunner slackens the leg-locking handwheel, releases the locating catch, and positions the plain leg. c. The M374A3 HE cartridge is constructed from pearlitic malleable cast iron and contains about 2.10 pounds of composition B explosive. News. ) or https:// means youve safely connected to the .gov website. a. He is also the squad driver. This round must be stored in a vertical position. b. He exposes 1 inch (25 millimeters) of cross-level shaft and folds the handle. b. f. If the above procedure fails to remove the misfire, the barrel must be kept horizontal. Target terrain, such as ice and dry sand, gives lowest burst heights, whereas water and wet ground give highest burst heights. Referring and realigning aiming posts ensure that all mortars are set on the same data.