The mortar is within two turns of center of traverse. d. When the barrel reaches the horizontal position, and not before, the assistant gunner moves the thumb of each hand over the muzzle. Types of rounds, classification, and characteristics for the 81-mm mortar, M29A1 (Standard B for the 81-mm mortar, M252). The bipod provides front support for the barrel and carries the gears necessary to lay the mortar. (2) The barrel is locked to the baseplate, and the open end of the socket points in the direction of fire. SMALL DEFLECTION AND ELEVATION CHANGES. Fuzes are not disassembled. He moves the mortar until the vertical line of the sight is aligned approximately on the aiming post. *FREE* shipping on qualifying offers. The 60mm mortar section is located in the weapons platoon of the rifle company, is armed with three 60mm mortars, and is 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. 4-10. 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 . 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. It is assembled with the M772A1 MTSQ. c. Upon receiving the command REFER, REALIGN AIMING POST, two actions take place at the same time in the mortar squad. This ensures a maximum traversing and elevating capability after making the movement. The safety/packing clip should be removed when the cartridge is unpacked. It has a time setting of up to 25 seconds. These cartridges are used first in subsequent firing so that once-opened stocks can be kept to a minimum. Red phosphorus/white phosphorus is used for screening, producing casualties, creating incendiary effects, and signaling. When a misfire occurs, any member of the squad immediately announces, "Misfire." The contents of ammunition containers are shown by markings. (3) The M256-series fuze has an SQ/IMP function only. M3A1 Baseplate He makes large deflection shifts by shifting the bipod assembly and keeps the bubbles level during firing. The gunner is given a deflection change in a fire command between 20 and 60 mils inclusive. It arms within a maximum of 2.50 seconds. The gunner places the announced deflection on the sight (without disturbing the lay of the weapon) and looks through the sightunit. The propelling charge consists of an ignition cartridge and removable propellant increments. At this command, the squad proceeds as follows: a. Illuminating is used for battlefield illumination and signaling. b. The fuzes may be used for day or night operations. High angles of approach (near vertical) give the lowest burst heights. After the mortar is mounted, the gunner makes a thorough check. In charge was the platoon commander - normally a lieutenant. The aluminum tail assembly has six integral fins equally spaced around the rear, which stabilize the round in flight. He indicates the initial direction of fire by pointing in that direction and commands ACTION. DESCRIPTION. When cartridges have been prepared for firing, but are not used, all powder increments and safety wires are replaced. b. It contains white phosphorus that produces white smoke on contact with air. The enemy will use them. The body is made of aluminum and brass. The fuze threads and fuze well threads are inspected for damage. Proximity-fuzed short cartridges, which are duds, contain a complete explosive train and impact element. (6) The primer cartridge is checked for damage or dampness. The M252 system . The gunner stands to the left side of the mortar where he can manipulate the sight, elevating handwheel, and traversing handwheel. The cartridge must not be fired below charge 3. It should be destroyed in accordance with standard procedures. The components of the mortar consist of a cannon, mount, and baseplate. 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. He is also the squad driver. This cartridge is ballistically matched to the M374A2, M374A1, and M375 HE cartridges, and weighs about 9.12 pounds. High explosive--M821, M889, M374-series, and M362. XM1210. The mortar should be within two turns of center of traverse when the task is compete. (8) To help minimize the occurrence of short rounds and or duds, unpackaged ammunition that has been dropped should not be fired. It provides illumination for about 60 seconds with 600,000 candlepower illumination. 60MM M224A1. Other armies count on 81mm mortar families. The M252 is highly accurate up to ranges of 4500m to 5700m depending on the The assistant gunner places his right hand palm up (1 inch from the muzzle end) under the BAD and his left hand palm down (1 inch from the muzzle end) on top. The squad leader points to the exact spot where the mortar is to be mounted. Correctly applying and performing these duties enables the mortar section to perform as an effective fighting team. 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. However, at temperatures above 32 degrees Fahrenheit and at angles greater than 1068 mils, the flight time is sufficient to permit arming. When firing under the control of an FDC, he reports to the FDC that mask clearance cannot be obtained at a certain elevation. 1:4 For the 81MM Mortar System: X NSN (LIN): 1015-01-441-3113 : STAFF SECTION, CLEANING, ARTILLERY 1:4: Powered by Hugo. The assistant gunner cleans the bore and swabs it dry. 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. The striker has been modified to be able to use German and Italian patterns of 81mm mortar . The mortar squad consists of five men (Figure 4-1). 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. In the U.S. Army and U.S. Marine Corps, it is normally deployed in the mortar platoon of an infantry battalion. Both the M90 and M90A1 propellants are in nine wax-tested, cotton cloth, bag increments assembled to the tail unit. Excess increments should not accumulate near the mortar positions but are removed to a designated place of burning and destroyed. If the primer is not dented, the round may be used again. . He levels all bubbles. (1) The M935 fuze has two function settings: impact and delay. It is constructed from ductile cast iron and contains about 1.5 pounds of cyclonite (RDX)/trinitrotoluene (TNT) composition explosive. The 81mm Mortar - The David of Modern Warfare | SOFREP The components of the mortar consist of a cannon, mount, and baseplate. (703) 614-3727, Office of the Chief Information Officer 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. (2) The breech plug is screwed tightly to the barrel. 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. (1) The barrel is clean and free from grease and oil both inside and out. 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. If it gets wet or dirty, it must be wiped off at once. The squad leader indicates the direction of fire when mounting. 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. When the baseplate is in position, the first ammunition bearer lowers the breech plug into the rotating socket and rotates the barrel a quarter of a turn to lock it. 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. FIRING TABLE FOR 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; AND HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A3B; AND CANNON, 155MM HOWITZER, M284 ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A5 AND HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A6 AND CANNON, 155MM HOWITZER, M199 ON HOWITZER, MEDIUM, TOWED, 155MM, M198 FIRING PROJECTILE, GUIDED, M712 (COPPERHEAD) WITH SHAPED TRAJECTORIES (S&I BY PROP SEE DETAILS, FOOTNOTES), PROVISIONAL AIMING DATA FOR CANNON, 155MM, HOWITZER, M185 ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, 109A1 HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, 109A1B HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A2 AND HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A3 HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A3B AND HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A4 AND CANNON, 155MM HOWITZER, M284 ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A5 AND HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A6 AND CANNON, 155MM HOWITZER, M199 ON HOWITZER, MEDIUM, TOWED, 155MM, M198 AND CANNON, 155MM HOWITZER, M776 ON HOWITZER, MEDIUM, TOWED, 155MM, M777A1 FIRING PROJECTILE, BASE-BURN, M864 AND M864A1 (S&I BY PROP SEE DETAILS, FOOTNOTES), PRELIMINARY AIMING DATA FOR CANNON, 155MM HOWITZER, M284 ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A6 AND CANNON, 155MM HOWITZER, M776 ON HOWITZER, MEDIUM, TOWED, 155MM, M777A2 FIRING PROJECTILE, HE, XM982 (S&I BY PROP SEE DETAILS, FOOTNOTES), PROVISIONAL AIMING DATA FOR CANNON, 155MM HOWITZER, M284 ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A6 AND CANNON, 155MM HOWITZER, M776 ON HOWITZER, MEDIUM, TOWED, 155MM, M777A2 FIRING PROJECTILE, HE, XM982 (S&I BY PROP SEE DETAILS, FOOTNOTES), PROVISIONAL AIMING DATA FOR CANNON, 155MM HOWITZER, M284 ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A6 AND CANNON, 155MM HOWITZER, M776 ON HOWITZER, MEDIUM, TOWED, 155MM, M777A2 FIRING PROJECTILE, HE, M982 (S&I BY PROP SEE DETAILS, FOOTNOTES), CANNON, 165-MM GUN, M135 ON COMBAT ENGINEER VEHICLE, FULL TRACKED, M728; FIRING CARTRIDGE, 165-MM, HEP, M123A1 AND 165-MM, TP-T, XM623 (S&I BY PROP SEE DETAILS, FOOTNOTES), CANNON, 175-MM GUN, M113 AND M113A1 ON GUN, FIELD ARTILLERY, SELF-PROPELLED: 175-MM, M107; FIRING PROJECTILE, HE, M437A2 AND M437A1 (S&I BY PROP SEE DETAILS, FOOTNOTES), RAPID FIRE TABLES FOR CALCULATION OF THE EXECUTIVE OFFICERS (XOS) MINIMUM QUADRANT ELEVATION WITH CANNON, 105MM HOWITZER, M20A1 ON HOWITZER, LIGHT, TOWED, 105MM, M119A1; HOWITZER, LIGHT, TOWED, 105MM, M119A2; HOWITZER, LIGHT, TOWED, 105MM, M119A3 FIRING WITH PROPELLING CHARGES, M67 AND M200 (S&I BY PROP SEE DETAILS, FOOTNOTES), RAPID FIRE TABLES FOR CALCULATION OF THE EXECUTIVE OFFICER S (XO S) MINIMUM QUADRANT ELEVATION WITH CANNON, 155MM HOWITZER, M284 ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A5/A6 AND CANNON, 155MM HOWITZER, M199 ON HOWITZER, MEDIUM, TOWED, 155MM, M198 AND CANNON, 155MM HOWITZER, M776 ON HOWITZER, MEDIUM, TOWED, 155MM, M777A1/A2 FIRING WITH PROPELLING CHARGES, M231, M232, AND M232A1 (S&I BY PROP SEE DETAILS, FOOTNOTES), RAPID FIRE TABLES FOR CALCULATION OF THE EXECUTIVE OFFICERS (XOS) MINIMUM QUADRANT ELEVATION WITH CANNON, 155MM HOWITZER, M284 ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A5; HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A6; AND HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A7, AND CANNON, 155MM HOWITZER, M776 ON HOWITZER, MEDIUM, TOWED, 155MM, M777A1 AND HOWITZER, MEDIUM, TOWED, 155MM, M777A2 FIRING WITH PROPELLING CHARGES, M231, M232, AND M232A1 (S&I BY PROPONENT, SEE DETAILS, FOOTNOTES), ADDENDUM TO FTR LANCE-B-1 FOR WARHEAD SECTION, GUIDED MISSILE, HE: M251 (U) (S&I BY PROP SEE DETAILS, FOOTNOTES), Search Army publications and forms by Number, Title, or Record Detail. MC Medical Guide; Client-side mods; TFAR 1.x for players; M821/M889 81mm HE Mortar Cartridges - GlobalSecurity.org The gunner unlocks the barrel clamp and rotates the barrel, unlocking the breech plug from the rotating socket of the baseplate. The standard infantry support weapon is the M-252 81mm mortar, which lobs a 10 lb. Ammunition is typed according to use (Table 4-2). The round has a burst height of 600 meters and provides illumination for about 60 seconds for an area of about 1,200 meters. He places the sight case and aiming posts to the left front of the mortar position. A safety latch located at the side of the recess is used to secure the ball. To set for delay, the selector slot should be rotated clockwise until it is aligned with the "D" mark on the ogive. . At the muzzle end is a cone-shaped blast attenuator device (BAD) that is fitted to reduce noise. The M301A3 cartridge has a cylindrical body that contains an illuminating candle and parachute assembly. FT 81-AI-3 Firing Tables Mortar, 81mm: M28A1 and M29 Mortar 81mm Self propelled M125A1 and M125 Carrier, 81mm Mortar Tracked XM755 ), FIRING TABLES FOR 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 AND HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A4 AND CANNON, 155MM HOWITZER, M284 ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A5 AND HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A6 AND CANNON, 155MM HOWITZER, M199 ON HOWITZER, MEDIUM, TOWED, 155MM, M198 AND CANNON, 155MM HOWITZER, M776 ON HOWITZER, MEDIUM, TOWED, 155MM, M777A1 FIRING PROJECTILE, HE, M483A1 (S&I BY PROP SEE DETAILS, FOOTNOTES), 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, M776 ON HOWITZER, MEDIUM, TOWED, 155MM, M777A1 FIRING PROJECTILE, HERA, M549 PROJECTILE, HERA, M549A1 (S&I BY PROP SEE DETAILS, FOOTNOTES), FIRING TABLES FOR 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, HERA, M549 AND PROJECTILE, HERA, M549A1 (S&I BY PROPONENT, SEE DEAILS, FOOTNOTES. The components of the mortar consist of a cannon, mount, and baseplate. Fort Belvoir, VA 22060 FM 23-90 Chptr 4 81-mm Mortar, M252 - GlobalSecurity.org (1) The rotating socket is free to move in a complete circle. b. MFCS Dismounted. U.S. Mortars of World War II - World War Media c. The first ammunition bearer ensures that each cartridge is clean, the safety pin is present, and the ignition cartridge is in good condition. 81MM M252A1. If water is not available, the gunner must stand clear of the mortar until the barrel is cool. These fuzes use a clockwork mechanism to delay functioning for a specific time. The mortar is then re-laid on the aiming posts using the traversing crank. c. The M374A3 HE cartridge is constructed from pearlitic malleable cast iron and contains about 2.10 pounds of composition B explosive. c. The gunner grasps both ends of the traverse screw assembly and supports the mortar during the subsequent drill. These are NDI items . .50 MACHINE GUN, M3; FIRING CARTRIDGE, CAL. The M1 was a derivative of the French mle 27/31 system (itself an improved form of the Stokes Trench Mortar of World War 1 fame) and slightly altered to suit American needs. 81 mm mortar - Wikipedia Ammunition Lot Number. It weighs about 9.05 pounds. c. The elevating shaft is contained in the elevating leg; to the left of the elevating leg is the elevating handwheel. (b) In selecting the exact mortar position, the leader looks quickly for mask clearance and overhead interference. .30, BROWNING, M1919A4 AND M2 (HEAVY BARREL), .30, M2 (REPRINTED W/BASIC INCL C1) (S&I BY PROP SEE DETAILS, FOOTNOTES), GUN, MACHINE: CAL. d. The gunner recovers the baseplate to the area designated by the squad leader. (3) Markings on rounds. e. Care, Handling, and Preservation. Disposal Precautions. PDF 81-mm MORTAR, M252 - GlobalSecurity.org One-quarter turn on the adjusting nut equals one turn of the traversing handwheel. The term "danger close" is included in the call for fire when there are friendly troops or positions within a prescribed distance of the target, specifically 600 meters for artillery or mortars . Mount, M177, in folded position. [Firing and Deflection Conversion Tables] - The Portal to Texas History Since phosphorus liquefies at about 100 degrees Fahrenheit, the ammunition is protected against an uneven rehardening of the filler. It is painted white with black markings. (5) With the exception of a few unused increments (within the same ammunition lot number) as replacements for defective increments, excess powder should be removed from the mortar position. Table 4-3. Identification. PDF Introduction to Crew Served Weapons B3m4078 Student Handout LHMBC. The M821A2/821A1/889A1 consists of the following major components: M935 Point Detonating Fuze or M734/734A1 Multi-Option Fuze. The M853 and M301A3 illuminating ammunition are described herein. He exposes 1 inch (25 millimeters) of cross-level shaft and folds the handle. It is used for records such as reports on condition, malfunctions, and accidents. The assistant gunner checks the bipod and ensures that--. 81mm, 82 mm & 120 mm Medium and Heavy Mortars - GICHD Indirect Fire Official websites use .mil The equipment is placed out the same as for the gunner's examination (Chapter 9). b. 81mm L16 | Weaponsystems.net If the barrel is hot, the gunner may then apply water to the outside of the barrel until it is cool. 9301 Chapek Road., Bldg.1458 Dropping may cause the propellant charges to ignite, causing bodily injuries. Each round is stenciled with the ammunition lot number, type of round, type of filler, and caliber. The M532 fuze is a radio doppler fuze that has a proximity (PROX) or SQ/IMP function. To prepare for firing, the slot is aligned in the striker with SQ or delay using the M18 fuze wrench. a. Fuze, PD, for 81mm mortar rounds, Italy, WWII, inert PDF Principles of Fire Support B2c2437 Student Handout The fuze arms and functions normally when fired at any angle of elevation between 0800 and 1406 mils at charges 1 through 9. on Amazon.com. 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. a. 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 . c. Crest Clearance. Each squad member should be able to perform all the following premount checks: a. The Mark 4 and 5 barrels were introduced during World War 2 and have a much increased range. 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. They use the M5 propelling charge that consists of eight cloth bags attached to the tail unit. On its right side, the clamp is recessed to receive the ball end of the locking rod. At the same time, the first ammunition bearer moves out on the double to realign the aiming posts. M224A1 60 MM LWCMS Mortar The 60mm mortar, M224A1 Lightweight Company Mortar System (LWCMS), is a smoothbore, muzzle loaded, high angle of fire weapon. When set at delay, the fuze train causes a 0.05-second delay before functioning. There is a selector on the lower shaft for non-delay or delay impact action. The fuze wrench, M18, assembles the fuze to the cartridge, and the bladed tip on the end sets PD-type fuzes. System (including basic issue items) Both the 60mm and 120mm mortar rounds use White Phosphorus. . Theme by TechDoc. This is the inert PD fuze type "IR-81" used by the Italians for their 81mm mortar rounds during WWII. End this starting train with not less than 1 meter of inert material (dry grass, leaves, or newspapers). Share sensitive information only on official, secure websites. 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) . It has four function settings: PRX (proximity) causes the cartridge to explode between 3 and 13 feet above the ground; NSB (near-surface burst) causes the cartridge to explode up to 3 feet above the ground; IM (impact) causes the cartridge to explode on contact; and DLY (delay) incorporates a 0.05-second delay in the fuze train before exploding the cartridge. This section discusses the. The following safety checks must be enforced before firing the mortar. The pile is covered with a double thickness of tarpaulin. M252 81mm Medium Extended Range Mortar - Specifications The M252 medium mortar offers a compromise between the light and heavy mortars. 0.50, BROWNING, M2; FIRING CARTRIDGE, ARMOR-PIERCING-INCENDIARY, CAL. However, since explosives are affected by moisture and high temperature, they must be protected. (4) The M567 fuze is an impact fuze that has a SQ/IMP or D function. 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. Range Minimum to maximum 83 to 5,608 meters Rate of Fire . 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. 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. Joint Tables of Allowance; PB - Professional Bulletins; STP - Soldier Training Publications; TC - Training Circulars; . 0.30, BROWNING, M1917A1; GUN, MACHINE: CAL.