At the muzzle end is a cone-shaped blast attenuator device (BAD) that is fitted to reduce noise. (e) If the mask is not regular throughout the sector of fire, the gunner determines the minimum mask clearance as described above. (1) Marking on container. 81mm 120mm 60mm . d. The M374A2, M374A1, and M374 HE cartridges are painted olive drab with yellow markings and are constructed from pearlitic malleable cast iron. FT 81-AI-3 Firing Tables Mortar, 81mm: M28A1 and M29 Mortar 81mm Self propelled M125A1 and M125 Carrier, 81mm Mortar Tracked XM755 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. 0.50, M8 (REPRINTED W/BASIC INCL C1-2) (S&I BY PROP SEE DETAILS, FOOTNOTES), FIRING TABLES FOR MACHINE GUN, CALIBER .50: BROWNING, M2 (HEAVY BARREL, TURRET TYPE) ON MOUNT, MACHINE GUN, TRAILER MOUNTED: MULTIPLE CALIBER .50 MACHINE GUN, M55 FIRING CARTRIDGE, CALIBER .50: API, M8 (S&I BY PROP SEE DETAILS, FOOTNOTES), FIRING TABLES FOR MACHINE GUN, CALIBER .50: FICED, M85 TANK, COMBAT, FULL TRACKED: 105MM GUN, M60 SERIES FIRING CARTRIDGE, CALIBER .50: API, M8 CARTRIDGE, CALIBER .50: API-T M20 CARTRIDGE, CALIBER .50: BALL, M33 CARTRIDGE, CALIBER .50: TRACER, M17 (S&I BY PROP SEE DETAILS, FOOTNOTES), MACHINE GUN, CAL. (2) The breech plug is screwed tightly to the barrel. If the barrel is cool enough to handle, the crew removes the round as described below. a. After the mortar is mounted, the gunner makes a thorough check. A locked padlock He rotates the socket so that the open end is pointing in the direction of fire. If, upon removal of the safety wire, a buzzing sound in the fuze is heard, the round should not be used. 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. PDF Principles of Fire Support B2c2437 Student Handout M252 81mm Medium Extended Range Mortar - Specifications Tabulated data. As soon as the sight data are announced, the gunner places it on the sight. The baseplate (Figure 4-5) is of one-piece construction, and supports and aligns the mortar for firing. When firing under the control of an FDC, he reports to the FDC that mask clearance cannot be obtained at a certain elevation. After the bands are broken and the box opened, the rounds should be removed by allowing them to roll out along the lid of the box (Figure 4-8). It uses the M205 propelling charge, consisting of four horseshoe-shaped increments fitted around the tail. The powder increments, mainly, should not be exposed to direct sunlight. He levels all bubbles. Indirect Fire M224A1 60 MM LWCMS Mortar The 60mm mortar, M224A1 Lightweight Company Mortar System (LWCMS), is a smoothbore, muzzle loaded, high angle of fire weapon. 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. (3) The securing strap is correctly located, securing the barrel clamps and buffers to the plain leg. a. Cartridges are shipped with a complete propelling charge, an ignition cartridge, and primer. (2) The fin and fuze assembly must be checked for tightness and damage. If water is not available, the gunner must stand clear of the mortar until the barrel is cool. [1] [2] Many countries use or used an 81 mm mortar in their armed forces. d. The first ammunition bearer stands to the right rear of the mortar. b. FT 81-AI-3 Firing Tables Mortar, 81mm: M28A1 and M29 Mortar 81mm Self propelled M125A1 and M125 Carrier, 81mm Mortar Tracked XM755 [US Army.] The gunner is given a deflection change in a fire command between 20 and 60 mils inclusive. It is assembled with the M772A1 MTSQ. M64A1 Sightunit. The 81mm mortar is a portable, mobile, medium mortar at the infantry's disposal. He releases the securing strap, loosens the leg-locking handwheel, and lowers the plain leg until the locating catch engages in the recess. (The handle of the wrench is turned counterclockwise.) MC Medical Guide; Client-side mods; TFAR 1.x for players; This section discusses the characteristics and nomenclature of each component (Figure 4-2). The contents of ammunition containers are shown by markings. c. The elevating shaft is contained in the elevating leg; to the left of the elevating leg is the elevating handwheel. Fort Belvoir, VA 22060 b. b. This section discusses the. The fuze threads and fuze well threads are inspected for damage. He tightens the leg-locking handwheel (ensuring the teeth are correctly meshed) and fastens the securing strap over the arm and around the buffers. 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. If the barrel is hot, the gunner may then apply water to the outside of the barrel until it is cool. The M751 fuze is the only dummy fuze used with the 81-mm mortar. Then he relocks the barrel clamp. An official website of the United States government. The fuze has a safety wire that must be removed before firing. However, since explosives are affected by moisture and high temperature, they must be protected. The following safety checks must be enforced before firing the mortar. It can be set from 3 to 55 seconds at half-second intervals. In any case, the gunner must ensure that the cartridge does not strike an obstacle. 81mm smoothbore mortar Barrel length 1.28 m Muzzle velocity 225 m/s Elevation +45 to +85 Traverse 18 Fire control Sights C2 indirect fire sight with illumination Firepower Rate of fire 20 rpm maximum 15 rpm normal 1 to 12 rpm sustained Range 5.650 m maximum 100 m minimum Media 81mm L16A2 A spring-loaded locating catch is behind the elevating gear housing, which locates the plain leg in its supporting position for level ground. Red phosphorus/white phosphorus--M819 and M375-series. The M375A3 cartridge is ballistically similar to the M374A3 (HE) cartridge. The mortar is within two turns of center of traverse. Figure 4-4. 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. 81mm Roll Controlled Guided Mortar (RCGM) - General Dynamics Ordnance The gunner then kicks the barrel several times with his heel in an attempt to dislodge the round. d. The gunner removes the sight from its case, mounts it on the mortar, and sets a deflection of 3200 mils and an elevation of 1100 mils. To prepare for firing, the slot is aligned in the striker with SQ or delay using the M18 fuze wrench. c. After the gunner has announced, "Up," the squad leader should check the mortar to determine if the exercise was performed correctly. TM - Technical Manuals (Range 9) TM - Technical Manuals (Range 10) TM - Technical Manuals (Range 11-4) TM - Technical Manuals (Range 11-5) . They are assembled with either an M524-series, M526-series, or M567 fuze. 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 cartridges are returned to their original containers. Agreed that mortars should generally be used close to the frontline. The ignition cartridge (with primer) is fitted into the base of the fin shaft. Their firing positions and principal duties are as follows: a. Additional information is included on an ammunition data card inside each container. a. He ensures that the firing pin recess is facing upwards. It is used for records such as reports on condition, malfunctions, and accidents. The fuze should already be fitted to the cartridge. The gunner unlocks the barrel clamp and rotates the barrel, unlocking the breech plug from the rotating socket of the baseplate. The M1 became the standard American . PDF 81-mm MORTAR, M252 - GlobalSecurity.org Close approach to crests, trees, towers, large buildings, parked aircraft, mechanized equipment, and similar irregularities causes functioning at heights greater than average level. Both the 60mm and 120mm mortar rounds use White Phosphorus. a. Before-firing checks include the following: (1) Ammunition should be free of moisture, rust, and dirt. He makes large deflection shifts by shifting the bipod assembly and keeps the bubbles level during firing. Trenches are dug to prevent water from flowing under the pile. 81-mm MORTAR, M252 The 81-mm mortar, M252, delivers timely, accurate fires to meet the . That is generally how I use mortars. He is also the squad driver. He places firing data on the sight and lays the mortar for deflection and elevation. MFCS Dismounted. 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. Range Minimum to maximum 83 to 5,608 meters Rate of Fire . b. The M374A2 and M374A1 cartridges are fitted with the M90A1 propelling charge. b. b. Figure 4-7. One-quarter turn on the adjusting nut equals one turn of the traversing handwheel. [Firing and Deflection Conversion Tables] - The Portal to Texas History The M751 is fitted with a smoke charge that operates on impact. The company level vehicles also carry a vehicle-mounted 120mm mortar, which is augmented by the 60mm M224 mortar for dismounted use. The 81-mm mortar, M252, is a smooth-bore, muzzle-loaded, high-angle-of-fire weapon. HE Guided Mortar is in development. If the round does not fire, the gunner tests the barrel for heat. This is the inert PD fuze type "IR-81" used by the Italians for their 81mm mortar rounds during WWII. The firing pin must be replaced and the bore swabbed. The fuze wrench, M18, assembles the fuze to the cartridge, and the bladed tip on the end sets PD-type fuzes. When the gunner is satisfied with his sight picture he announces, "Up.". The wrench (P/N 9349539) sets M772 MT and M768 time fuzes. (3) The M84A1 fuze is a single-purpose, tungsten-ring, mechanical-time fuze used with the 81-mm M301A3 illumination cartridge. The cartridge is dropped down the barrel, fin-end first. 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. LHMBC. The striker has been modified to be able to use German and Italian patterns of 81mm mortar . The M734 multioption fuze is the only one used with the 81-mm mortar. Disposal Precautions. The traversing screw assembly is fitted to the clamp assembly, which is pivoted in the center on an arm attached to the elevating leg. M821/M889 81mm HE Mortar Cartridges - GlobalSecurity.org If it is necessary to leave the ammunition uncovered, it should be raised on dunnage at least 6 inches above the ground. This is accomplished by depressing the barrel until the top of the mask is clear. on Amazon.com. 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. The same procedure for aligning the far aiming post is used to align the near aiming post. Designed by Thingsym. The body is made of aluminum and brass. He positions the lower barrel clamp against the lower stop band on the barrel and secures the upper barrel clamp. The propellant train (except the training cartridge) consists of an ignition cartridge and propellant charges. 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. He exposes 1 inch (25 millimeters) of cross-level shaft and folds the handle. The cartridge uses the M205 propelling charge and is assembled with the M567 or M524-series fuze. 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. If the line of sight clears the mask, it is safe to fire. Additionally, they carry the 81mm M252 mortar that can only be used in a dismounted capacity. b. M252 mortar - Wikipedia b. 4-4. It is light enough to be portable when broken down into. b. c. The moisture-resistant seal of the container is broken when the ammunition is to be used. End this starting train with not less than 1 meter of inert material (dry grass, leaves, or newspapers). This ensures that the mortar does not fire should the round slip down the barrel during the subsequent drills. 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. General Dynamics Ordnance and Tactical Systems is the leading manufacturer of propellants for 60mm, 81mm and 120mm Mortar Systems. Attached to the arm is the cross-leveling mechanism, which is attached to the clamp assembly at its upper end. He opens the cross-level handwheel, traversing handwheel, and barrel clamp. Training practice--M879, M880, M68, and sabot. (8) To help minimize the occurrence of short rounds and or duds, unpackaged ammunition that has been dropped should not be fired. The M252 system . It has a time setting of up to 50 seconds. (3) The circlip is correctly located, securing the rotating socket to the baseplate. a. 90th IDPG IMA 81mm Mortar Review MFCS Mounted. The assistant gunner attempts to maintain the traversing mechanism on a horizontal plane. (1) The rotating socket is free to move in a complete circle. The ammunition that can be fired by the 81-mm mortar, M252, is identified and described herein. However, at temperatures above 32 degrees Fahrenheit and at angles greater than 1068 mils, the flight time is sufficient to permit arming. WP cartridges are stored with the fuze end up. (5) Four inches of elevation shaft are exposed, and the shaft is not bent. The American M1 81mm Mortar, like the upcoming M2 60mm Mortar, was based on a French design by Edgar William Brandt (1880-1960). (a) Since the mortar is normally mounted in defilade, there could be a mask such as a hill, tree, building, or rise in the ground. d. When the barrel reaches the horizontal position, and not before, the assistant gunner moves the thumb of each hand over the muzzle. The gunner should expose 6 inches (150 millimeters) of elevation shaft and center the buffer carrier. The M252 medium mortar offers a compromise between the light and heavy mortars. The assistant gunner exposes 8 inches (200 millimeters) of elevation shaft, leaving the elevation handwheel unfolded. (6) The primer cartridge is checked for damage or dampness. Dropping may cause the propellant charges to ignite, causing bodily injuries. It engages the 1 3/4-inch flats on the setting ring or the fuze head. (4) The bipod locking latch is locked, securing the barrel clamps. The principal factors affecting height of burst are the angle of approach to the target and the reflectivity of the target terrain. 60MM M224A1. b. (2) Burn all dead grass or brush within 30 meters around the burning place. He moves the mortar until the vertical line of the sight is aligned approximately on the aiming post. The cartridge uses the M218 propelling charge, which consists of four horseshoe-shaped increments fitted around the tail. While the assistant gunner supports the barrel, the gunner slackens the leg-locking handwheel, releases the locating catch, and positions the plain leg. Lock Ammunition is made and packed to withstand all conditions ordinarily encountered in the field. 107 Army Pentagon 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. 81mm ML 3-inch | Weaponsystems.net In the U.S. Army and U.S. Marine Corps, it is normally deployed in the mortar platoon of an infantry battalion. c. The M374A3 HE cartridge is constructed from pearlitic malleable cast iron and contains about 2.10 pounds of composition B explosive. The M819 cartridge (M252 only) has a cylindrical body and contains red phosphorus that produces white smoke on contact with air. PDF Principles of Fire Support B2c0289xq Student Handout Excess increments should not accumulate near the mortar positions but are removed to a designated place of burning and destroyed. The components of the mortar consist of a cannon, mount, and baseplate. He performs other duties as the squad leader directs. To dismount the mortar, the squad leader commands, OUT OF ACTION. He lays for deflection, taking the proper sight picture. Those cartridges assembled with the M524 (A1, A2, A3, or A4) fuze are for use by the US Marine Corps and US Navy only. 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. If the mortar section is to operate quickly and effectively in accomplishing its mission, mortar squad members must be proficient in individually assigned duties. The floating firing pin located within the primer has approximately 1/16 of an inch to move around. Illuminating is used for battlefield illumination and signaling. The M821/M889 are 81mm HE Mortar Cartridges. If he is not within 20 mils, the gunner and assistant gunner must make another large shift before moving on. It weighs about 9.05 pounds. Types of rounds, classification, and characteristics for the 81-mm mortar, M252. 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. (5) Do not leave unused increments unburned in combat operational areas. Several types of RP/WP ammunition are described herein. From introduction up to halfway World War 2 the ML 3-inch had a poor range of up to 1.45 km. (1) The M935 fuze has two function settings: impact and delay. They contain about 2.10 pounds of composition B explosive. All PD fuzes are superquick--detonate on impact. The squad leader indicates the direction of fire when mounting. (703) 614-3727, Office of the Chief Information Officer At the same time, the first ammunition bearer moves out on the double to realign the aiming posts. The 81mm weapons platoon consisted of the headquarters platoon and four mortar squads. When cartridges have been prepared for firing, but are not used, all powder increments and safety wires are replaced. Correct way to open an ammunition box. To make the shift, the gunner places the fingers of his right hand in the muzzle and his left hand on the left leg. b. They are painted light green with red markings and one narrow yellow band. After the 30-minute waiting period, the dud is still dangerous but can be approached and removed carefully or destroyed in place by qualified disposal personnel. This cartridge is ballistically matched to the M374A2, M374A1, and M375 HE cartridges, and weighs about 9.12 pounds. This ensures a maximum traversing and elevating capability after making the movement. The gunner removes the sight and places it in the case with 3200 deflection and 0800 elevation indexed. At this command, the squad proceeds as follows: a. 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. PDF Tabular Firing Tables - United States Army (See FM 7-90 for a discussion of the duties of the platoon headquarters.). f. If the above procedure fails to remove the misfire, the barrel must be kept horizontal. The fuze is not intended to function at charge 0. Washington DC 20310-0107, ADRP - Army Doctrine References Publications, ATTP - Army Tactics, Techniques, and Procedures, FY Publication Status Report (CAC required for access), Publishing Resources (CAC required for access), PC/PCO/FMO/EPCO Directory (CAC required for access), usarmy.pentagon.hqda-apd.mbx.customer-service@army.mil, GUN, MACHINE, CAL. 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 . An 81 mm mortar is a medium-weight mortar. Its range and explosive power is greater than the M224, yet it is still light enough to be man . The gunner stands to the left side of the mortar where he can manipulate the sight, elevating handwheel, and traversing handwheel. The removable increments are fitted onto or around the shaft, depending on their type. 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. 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. (1) The M772A1 fuze is a MTSQ. This round may be stored in a horizontal position. These fuzes use a clockwork mechanism to delay functioning for a specific time. Mount, M177, in folded position. The gunner checks the baseplate and ensures that--. He has the duty of preparing the ammunition and passing it to the assistant gunner. 120mm IHE grenade DM91. b. Propelling charges are covered or protected from dampness or heat. He places the sight case and aiming posts to the left front of the mortar position. Identification. (c) The gunner determines mask and overhead clearance by sighting along the barrel with his eye near the breech plug. The M252 81mm medium extended range mortar (see diagram below) is a crew-served, smooth bore, muzzle loaded, high angle of fire weapon system. PDF IMLC EQUIPMENT SUPPLY LIST - United States Army Short cartridges can be expected when firing below charge 4. c. Authorized Cartridges. Safety before firing is provided by a safety wire, which must be removed just before firing. (4) The M567 fuze is an impact fuze that has a SQ/IMP or D function. Theme by TechDoc. It is constructed from ductile cast iron and contains about 1.5 pounds of cyclonite (RDX)/trinitrotoluene (TNT) composition explosive. If not, he may still fire at the desired range by selecting a charge zone having a higher elevation. Army Publishing Directorate There is a selector on the lower shaft for non-delay or delay impact action. c. The assistant gunner disengages the barrel clamps and moves the bipod from the immediate area of the mortar position. 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. The barrel clamps are then closed. b. As soon as the sight data are announced, the gunner places it on the sight, lays the mortar for elevation, and traverses onto the aiming post by turning the traversing handwheel and adjusting nut in the same direction. 120MM Mortar System. U.S. Mortars of World War II - World War Media c. The assistant gunner stands to the right of the mortar, facing the barrel and ready to load. The squad leader stands behind the mortar where he can command and control his squad.
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