These cartridges are used first in subsequent firing so that once-opened stocks can be kept to a minimum. VERY NICE condition! Mortar, 81mm M1 - Military Factory The air burst over average types of soil ranges from 1 to 6 meters, depending on the angle of approach. It is set using the bladed end of the M18 fuze wrench. The tabulated data of the 81-mm mortar, M252, are shown in Table 4-1. When the gunner is satisfied with his sight picture he announces, "Up.". Both legs are fitted with a disk-shaped foot with a spike beneath to prevent the mount from slipping. c. The first ammunition bearer ensures that each cartridge is clean, the safety pin is present, and the ignition cartridge is in good condition. If it gets wet or dirty, it must be wiped off at once. When set at delay, the fuze train causes a 0.05-second delay before functioning. When firing under the control of an FDC, he reports to the FDC that mask clearance cannot be obtained at a certain elevation. Fired . The 81-mm mortar, M252, is a smooth-bore, muzzle-loaded, high-angle-of-fire weapon. M64A1 Sightunit. 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. He uses the chain of command to assist him in effecting his command and supervising duties. 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 . Safety before firing is provided by a safety wire, which must be removed just before firing. He releases the securing strap, loosens the leg-locking handwheel, and lowers the plain leg until the locating catch engages in the recess. PDF Principles of Fire Support B2c0289xq Student Handout They use the M5 propelling charge that consists of eight cloth bags attached to the tail unit. g. The barrel clamps can be moved along the barrel to counter large changes in elevation. d. The ammunition is protected from mud, sand, dirt, and water. The bipod provides front support for the barrel and carries the gears necessary to lay the mortar. 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. b. Its range and explosive power is greater than the M224, yet it is still light enough to be man . The Mark 4 and 5 barrels were introduced during World War 2 and have a much increased range. 4-12. There is a selector on the lower shaft for non-delay or delay impact action. 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 lower clamp is shaped and bored on each side to house the buffer cylinders. The M301A3 cartridge has a cylindrical body that contains an illuminating candle and parachute assembly. The round has a burst height of 600 meters and provides illumination for about 60 seconds for an area of about 1,200 meters. The cartridge is painted light green and has red markings and one narrow yellow band. Mortar Weapon Systems - USAASC It is especially useful if the baseplate sinks deep into the ground during prolonged firing. 0.50, BROWNING, M2; FIRING CARTRIDGE, ARMOR-PIERCING-INCENDIARY, CAL. The leg-locking handwheel must then be tightened, ensuring the teeth are correctly meshed. The first ammunition bearer holds the barrel until the assistant gunner has removed the mount. The M29 would become the standard American mortar in the upcoming Vietnam War. From introduction up to halfway World War 2 the ML 3-inch had a poor range of up to 1.45 km. The contents of ammunition containers are shown by markings. c. The assistant gunner stands to the right of the mortar, facing the barrel and ready to load. .50 MACHINE GUN, M55 AND MACHINE GUN, CAL. Then he relocks the barrel clamp. While the assistant gunner supports the barrel, the gunner slackens the leg-locking handwheel, releases the locating catch, and positions the plain leg. It is designed to be fired in the indirect fire mode, cannot be fired handheld, and normally utilizes a FDC. The mortar squad consists of five men (Figure 4-1). SMALL DEFLECTION AND ELEVATION CHANGES. They function normally in light rain; however, heavy rain, sleet, or snow can cause an increase in the number of early bursts. Training practice is used only for training. The 81mm mortar rounds use Red Phosphorus as the smoke generating agent. An ammunition lot number is assigned to each ammunition lot, which is marked on each cartridge and packing container. Agreed that mortars should generally be used close to the frontline. The 81-mm mortar, M252, is a smooth-bore, muzzle-loaded, high-angle-of-fire weapon. Training practice--M879, M880, M68, and sabot. Ammunition is typed according to use (Table 4-2). The gunner is given an administrative command to lay the mortar on a deflection of 2860 or 2740 mils. (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. 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. When a large number of cartridges are needed for a mission, they may be removed from the containers and prepared. An official website of the United States government. The aluminum tail assembly has six integral fins equally spaced around the rear, which stabilize the round in flight. Cartridges assembled with the M532 fuze must be fired above charge 0. a. They are fuzed with the M524-series, M256-series, or M532. 81mm ML 3-inch | Weaponsystems.net c. After the gunner has announced, "Up," the squad leader should check the mortar to determine if the exercise was performed correctly. If the round does not fire, the gunner tests the barrel for heat. a. Point-Detonating. (1) Marking on container. He makes large deflection shifts by shifting the bipod assembly and keeps the bubbles level during firing. 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. 81mm Roll Controlled Guided Mortar (RCGM) - General Dynamics Ordnance The cartridges are painted olive drab with yellow markings. An air cavity can form on one side of a cartridge to unbalance it, causing instability in flight. 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 entire squad stays with the mortar. The propelling charges are assembled around the fin assembly shaft. Proximity-fuzed short cartridges, which are duds, contain a complete explosive train and impact element. REFERRING OF THE SIGHT AND REALIGNMENT OF AIMING POSTS USING M64 SIGHT. FT 81-AI-3 Firing Tables Mortar, 81mm: M28A1 and M29 Mortar 81mm Self (1) The barrel is clean and free from grease and oil both inside and out. When a misfire occurs, any member of the squad immediately announces, "Misfire." As soon as the sight data are announced, the gunner places it on the sight. Normally, it can be moved by hand, although this may be difficult to do if the mortar is moved through a large arc. At the command, MARCH ORDER, the squad places the mortar, equipment, and ammunition in the squad vehicle and trailer. It uses the M205 propelling charge, consisting of four horseshoe-shaped increments fitted around the tail. The fuze setter, M25, sets M84-series time fuzes. Table 4-1. Correct way to open an ammunition box. 81mm 120mm 60mm . 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. Red phosphorus rounds can be fired from the M29/M29A1 at a reduced charge (maximum charge = charge 2). Figure 4-8. The platoon leader commands the platoon and supervises the training of the elements. (2) The barrel is locked to the baseplate, and the open end of the socket points in the direction of fire. The principal factors affecting height of burst are the angle of approach to the target and the reflectivity of the target terrain. e. Dummy. The table on the right describes the three most common setups. He opens the cross-level handwheel, traversing handwheel, and barrel clamp. The vertical cross line of the sight is on the left edge of the aiming point. High angles of approach (near vertical) give the lowest burst heights. The cartridge uses the M218 propelling charge, which consists of four horseshoe-shaped increments fitted around the tail. 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. This is the inert PD fuze type "IR-81" used by the Italians for their 81mm mortar rounds during WWII. Red phosphorus/white phosphorus is used for screening, producing casualties, creating incendiary effects, and signaling. ) or https:// means youve safely connected to the .gov website. General Dynamics Ordnance and Tactical Systems is the leading manufacturer of propellants for 60mm, 81mm and 120mm Mortar Systems. a. Before-firing checks include the following: (1) Ammunition should be free of moisture, rust, and dirt. Overhead interference can be branches of trees or roofs of buildings. 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. a. These propellants are flash-suppressed and clean burning resulting in minimum residue, flash and blast overpressure. b. This action breaks an internal sheet pin and internal wire, thereby disabling the proximity function. The mortar is within two turns of center of traverse. This cartridge is ballistically matched to the M374A2, M374A1, and M375 HE cartridges, and weighs about 9.12 pounds. The striker has been modified to be able to use German and Italian patterns of 81mm mortar . They should not be approached for 5 minutes or disturbed for at least 30 minutes after firing. 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. The components of the mortar consist of a cannon, mount, and baseplate. 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 . M821/M889 81mm HE Mortar Cartridges - GlobalSecurity.org