It can be set from 3 to 55 seconds at half-second intervals. 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. It uses the M205 propelling charge, consisting of four horseshoe-shaped increments fitted around the tail. Training practice is used only for training. (5) Four inches of elevation shaft are exposed, and the shaft is not bent. The M252 medium mortar offers a compromise between the light and heavy mortars. He is also the squad driver. He stands to the rear of the baseplate and supports the barrel until the bipod is fitted. M3A1 Baseplate 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. .50: BROWNING, M2 (HEAVY BARREL, TURRET TYPE) ON MOUNT, MACHINE GUN, TRAILER MTD: MULTIPLE CAL. LARGE DEFLECTION AND ELEVATION CHANGES. 60mm, 81mm, and 120mmMortar Increments. He tightens the leg-locking handwheel (ensuring the teeth are correctly meshed) and fastens the securing strap over the arm and around the buffers. He exposes 4 inches (100 millimeters) of elevation shaft and folds the handle. The M751 is fitted with a smoke charge that operates on impact. If he is not within 20 mils, the gunner and assistant gunner must make another large shift before moving on. The mortar also offered the promised increase in range as well, allowing fire teams to engage the enemy at distance. There must not be a visible gap between the fuze and cartridge body. c. Upon receiving the command REFER, REALIGN AIMING POST, two actions take place at the same time in the mortar squad. a. Point-Detonating. . b. The M819 cartridge (M252 only) has a cylindrical body and contains red phosphorus that produces white smoke on contact with air. Examples are: c. The elevating shaft is contained in the elevating leg; to the left of the elevating leg is the elevating handwheel. Burst Height. Prev - Mk6 Mortar range table for charge 0 Next - Mk6 Mortar range table for charge 2 . The cartridge is painted light green with black markings and one narrow brown band. (2) The M524-series fuze has two function settings: superquick/impact (SQ/IMP) and delay. The second page includes a chart with range and deflection (presumably for the same kind of shells), as well as notes which give additional instructions. The fuze is not intended to function at charge 0. The first table is a chart that shows range and elevation for firing particular mortar shells. 120MM Mortar System. The terms cannon and barrel are used interchangeably in this chapter. The propelling charge consists of an ignition cartridge and removable propellant increments. a. Before-firing checks include the following: (1) Ammunition should be free of moisture, rust, and dirt. He maintains the ammunition for firing and provides local security for the mortar position. The floating firing pin located within the primer has approximately 1/16 of an inch to move around. Secure .mil websites use HTTPS 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. Dropping may cause the propellant charges to ignite, causing bodily injuries. 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. .50 MACHINE GUN, M3; FIRING CARTRIDGE, CAL. The fuze arms and functions normally when fired at any angle of elevation between 0800 and 1406 mils at charges 1 through 9. The cartridge uses the M218 propelling charge, which consists of four horseshoe-shaped increments fitted around the tail. f. Ammunition should be stored under cover. b. The same procedure for aligning the far aiming post is used to align the near aiming post. 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. While the assistant gunner supports the barrel, the gunner slackens the leg-locking handwheel, releases the locating catch, and positions the plain leg. The fuze has a safety wire that must be removed before firing. It provides illumination for about 60 seconds with 600,000 candlepower illumination. 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. Complete cartridges are always handled with care. The propellant increments are ignited, which produce rapidly expanding gases that force the cartridge from the barrel. General Dynamics Ordnance and Tactical Systems is the leading manufacturer of propellants for 60mm, 81mm and 120mm Mortar Systems. 4-11. 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. Safety before firing is provided by a safety wire, which must be removed just before firing. An official website of the United States government. ), 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. It is designed to be fired in the indirect fire mode, cannot be fired handheld, and normally utilizes a FDC. [1] [2] Many countries use or used an 81 mm mortar in their armed forces. Tabulated data. WP cartridges are stored with the fuze end up. Table 4-3. b. M327 mortar is an extended range mortar system operated by Marine Corps Artillery Units. It has two types: type 1 resembles the M734 fuze, and type 2 resembles the M935 fuze. If the primer is not dented, the round may be used again. The 81mm weapons platoon consisted of the headquarters platoon and four mortar squads. MFCS Mounted. Swifty 3 from scratch; Swifty 3 split-repo setup; Swifty Troubleshooting; Mods. It has no safety pins or wires to reduce preparation time. HE Guided Mortar is in development. Red phosphorus cartridges (M252 only) are stored the same as HE cartridges. 4-4. These fuzes use a clockwork mechanism to delay functioning for a specific time. The M853 and M301A3 illuminating ammunition are described herein. System (including basic issue items) It is light enough to be portable when broken down into. It uses the M772 mechanical time fuze and weighs about 10.6 pounds. b. The increments are individually wrapped with waterproof bags that are not removed. (4) The M567 fuze is an impact fuze that has a SQ/IMP or D function. 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. Each round is stenciled with the ammunition lot number, type of round, type of filler, and caliber. If the situation allows for a longer waiting period, the dud can be considered safe for handling after 40 hours. Short cartridges can be expected when firing below charge 4. Target terrain, such as ice and dry sand, gives lowest burst heights, whereas water and wet ground give highest burst heights. (4) The leg-locking handwheel is hand tight. Ammunition Lot Number. The gunner removes the sight and places it in the case with 3200 deflection and 0800 elevation indexed. 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. He places his thumbs alongside the forefingers, being careful to keep both hands away from the muzzle. The squad leader notifies the FDC of the minimum mask clearance elevation. 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. The safety/packing clip should be removed when the cartridge is unpacked. e. The squad leader picks up the aiming posts and sight. Normally, it can be moved by hand, although this may be difficult to do if the mortar is moved through a large arc. The removable increments are fitted onto or around the shaft, depending on their type. (2) The fin and fuze assembly must be checked for tightness and damage. (3) The M84A1 fuze is a single-purpose, tungsten-ring, mechanical-time fuze used with the 81-mm M301A3 illumination cartridge. e. The assistant gunner passes the round to the first ammunition bearer who inspects it for the cause of the misfire. M224A1 60 MM LWCMS Mortar The 60mm mortar, M224A1 Lightweight Company Mortar System (LWCMS), is a smoothbore, muzzle loaded, high angle of fire weapon. (1) The rotating socket is free to move in a complete circle. They are painted light green with red markings and one narrow yellow band. More uniform firing is obtained if ammunition is kept at the same temperature. Fort Belvoir, VA 22060 (703) 614-3727, Office of the Chief Information Officer The assistant gunner attempts to maintain the traversing mechanism on a horizontal plane. Disposal Precautions. The mount consists of elevating and traversing mechanisms and a bipod (Figure 4-4). Mount, M177, in folded position. Ammunition is made and packed to withstand all conditions ordinarily encountered in the field. 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 mortar is mounted, the gunner makes a thorough check. This section discusses the characteristics and nomenclature of each component (Figure 4-2). d. The ammunition is protected from mud, sand, dirt, and water. Correct way to open an ammunition box. The components of the mortar consist of a canon, sight, mount, and baseplate. The leg-locking handwheel must then be tightened, ensuring the teeth are correctly meshed. The sight bracket is attached to the buffer carrier, which is fitted to the traversing screw assembly. REFERRING OF THE SIGHT AND REALIGNMENT OF AIMING POSTS USING M64 SIGHT. (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. The squad leader indicates the direction of fire when mounting. A safety latch located at the side of the recess is used to secure the ball. Any target that requires that elevation, or a lower one, cannot be engaged from that position. (1) The M935 fuze has two function settings: impact and delay. They should not be approached for 5 minutes or disturbed for at least 30 minutes after firing. In any case, the gunner must ensure that the cartridge does not strike an obstacle. 1:4 For the 81MM Mortar System: X NSN (LIN): 1015-01-441-3113 : STAFF SECTION, CLEANING, ARTILLERY 1:4: 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 . The fuze should already be fitted to the cartridge. It is fitted with a standard pull wire and safety pin that are removed immediately before firing. The M375 cartridge uses the M90 propelling charge while the M375A2 and M375A1 cartridges use the M90A1 propelling charge. At the command, MARCH ORDER, the squad places the mortar, equipment, and ammunition in the squad vehicle and trailer. a. A securing strap is attached to the plain leg for securing the bipod in the folded position. Figure 4-7. It has a time setting of up to 25 seconds. The gunner is given a deflection change in a fire command between 20 and 60 mils inclusive. REFER DEFLECTION TWO EIGHT SEVEN FIVE (2875), REALIGN AIMING POSTS. d. When the barrel reaches the horizontal position, and not before, the assistant gunner moves the thumb of each hand over the muzzle. It is used for records such as reports on condition, malfunctions, and accidents. The fuze body is graduated from 0 to 50 seconds in 2-second intervals; 10-second intervals are indicated by bosses. The cannon has a crew-removable breech plug and firing pin. This action breaks an internal sheet pin and internal wire, thereby disabling the proximity function. Correctly applying and performing these duties enables the mortar section to perform as an effective fighting team. Both the 60mm and 120mm mortar rounds use White Phosphorus. 0.50, BROWNING, M2; FIRING CARTRIDGE, ARMOR-PIERCING-INCENDIARY, CAL. No tools are needed to set the fuze, and the setting can be changed several times without damaging the fuze. (6) The primer cartridge is checked for damage or dampness. In charge was the platoon commander - normally a lieutenant. ) or https:// means youve safely connected to the .gov website. SMALL DEFLECTION AND ELEVATION CHANGES. He must not stand directly behind the mortar. 107 Army Pentagon b. high-explosive bomb at a range of about three miles. 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. All mortar cartridges are painted to prevent rust and to identify their type. If the fuze does not function as set, it automatically functions at the next lower setting. The tabulated data of the 81-mm mortar, M252, are shown in Table 4-1. The bipod provides front support for the barrel and carries the gears necessary to lay the mortar. Proximity-fuzed short cartridges, which are duds, contain a complete explosive train and impact element. Fuzes are not disassembled. The cartridge is dropped down the barrel, fin-end first. The fuze body is graduated from 0 to 25 seconds in 1-second intervals; 5-second intervals are indicated by bosses. (c) The gunner determines mask and overhead clearance by sighting along the barrel with his eye near the breech plug. A lock ( The M532 fuze is a radio doppler fuze that has a proximity (PROX) or SQ/IMP function. 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). (4) Extra increments are removed if the cartridge is to be fired with less than full charge. 81-mm MORTAR, M252 The 81-mm mortar, M252, delivers timely, accurate fires to meet the . (1) The barrel is clean and free from grease and oil both inside and out. .30 BROWNING, M1917 AND M1917A1; GUN, MACHINE, CAL. The 60mm mortar section is located in the weapons platoon of the rifle company, is armed with three 60mm mortars, and is Both the M90 and M90A1 propellants are in nine wax-tested, cotton cloth, bag increments assembled to the tail unit. During training, the gunner may use the driving stake from the aiming post case. When cartridges have been prepared for firing, but are not used, all powder increments and safety wires are replaced. Their firing positions and principal duties are as follows: a. When a misfire occurs, any member of the squad immediately announces, "Misfire."