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Military


CHAPTER 10

AMMUNITION


10-1. REFERENCES

The combination of current and developmental ammunition with that being developed makes it essential that battery supervisors keep current on the latest changes. The following references will help them:

a. TM 9-1300-251-20, Table 3-2, gives detailed information on ammunition component inspection criteria. Chapter 3 explains how to correct any deficiencies noted. Appendix M indicates what maintenance the crew and ammunition sections are authorized to perform.

b. TM 43-0001-28 gives detailed characteristics of primers, projectiles, propellants, and fuzes. It includes combination and compatibility charts for all artillery weapons and ammunition components.

c. TM 9-1300-206 gives detailed information on complete precautions for handling artillery ammunition.

d. The operator's manual for the weapon system gives information on the ammunition authorized for use with that system.

e. Appendix M to this publication outlines characteristics of FA cannons, and Appendix N discusses interchangeability of ammunition for those weapons.

10-2. EXTERIOR COMPONENTS OF AN ARTILLERY PROJECTILE

Since the first projectile was manufactured, the demand for greater accuracy and greater range has influenced projectile design. Without specifically constructed shapes and exterior parts, there would be no standard ballistic characteristics for any group or type of projectiles. A lack of ballistic standardization would prevent the computation of firing tables. Modern projectiles are designed for maximum stability and minimum air resistance in flight. The exterior components of an artillery projectile are shown in Figure 10-1 and explained below.

a. Eyebolt Lifting Plugs and Fuze Well Plugs. A separate-loading projectile has an eyebolt lifting plug. Other types of projectiles have metal hex-head or plastic closing plugs. The plug is for lifting; to keep the fuze well clean, dry, and free of foreign matter; and to protect the fuze well threads. The plug is removed, and the appropriate fuze is inserted at the firing position. Some special-purpose semifixed projectiles are issued with the fuzes already assembled in the projectile.

b. Ogive. The ogive is the curved portion of a projectile between the fuze well and the bourrelet. It streamlines the forward portion of the projectile. The curve of the ogive usually is the arc of the circle, the center of which is located in a line perpendicular to the axis of the projectile and the radius of which is generally 6 to 11 calibers.

c. Bourrelet. The bourrelet is an accurately machined surface that is slightly larger than the body and located immediately to the rear of the ogive. It centers the forward part of the projectile in the tube and bears on the lands of the tube. When the projectile travels through the bore, only the bourrelet and the rotating band of the projectile bear on the lands of the tube.

d. Body. The body is the cylindrical portion of the projectile between the bourrelet and the rotating band. It is machined to a smaller diameter than the bourrelet to reduce the projectile surface in contact with the lands of the bore. The body contains most of the projectile filler.

e. Rotating Band. The rotating band is a cylindrical ring of comparatively soft metal that is pressed into a knurled, or roughened, groove near the base of the projectile. It mates with the forcing cone of the tube to eliminate gas wash (blow-by) and to provide forward obturation. The rotating band, in conjunction with the rifling of the tube, imparts spin to the moving projectile. A properly rammed separate-loading projectile is held in the tube at all angles of elevation by the wedging action of the rotating band against the forcing cone.

f. Obturating Band. On some projectiles, there is a nylon obturating band below the rotating band to help in forward obturation. Two examples of 155-mm projectiles with this type of a band are the illuminating round and the high-explosive rocket-assisted round.

g. Base. The base is that portion of the projectile below the rotating band or obturating band. The most common type is known as the boattail base. This type of base streamlines the base of the projectile, gives added stability in flight, and minimizes deceleration by reducing the vacuum-forming eddy currents in the wake of the projectile as it passes through the atmosphere.

h. Base Cover. The base cover is a metal cover that is crimped, caulked or welded to the base of the projectile. It prevents hot gases of the propelling charge from coming in contact with the explosive filler of the projectile through possible flaws in the metal of the base.

10-3. PROJECTILE PAINTING AND MARKING

The main reason for painting a projectile is to prevent rust. However, painting is also used to identify the various types of ammunition.

a. Identification. The basic colors used for many years were olive drab (OD) for high-explosive rounds, gray for chemical rounds, blue for practice rounds, and black for drill rounds. A system of contrasting color markings or bands in addition to the basic color has also been used to identify the particular type of high explosive or chemical used as a filler. Color coding of recently produced projectiles is somewhat different. For example, illuminating and smoke rounds are no longer painted gray, the basic color for chemical shells. Illuminating rounds are now painted basically white or olive drab, and the smoke rounds are painted green. The basic color for dummy ammunition has been changed to bronze.

b. Weight. Variations in weight are inherent in the manufacture of projectiles. Since a high degree of accuracy is required in artillery firing, one must compare the data stenciled on the projectile (Figure 10-2) with the data provided in the firing tables to obtain the proper ballistic corrections. The weight zone marking symbols for projectiles are shown in Table 10-1.

c. Ammunition Lot Number. When ammunition is manufactured, an ammunition lot number is assigned in accordance with pertinent specifications. This lot number is an essential part of the ammunition marking. When the size of the item permits, this lot number is stamped or marked on the item itself and on all packing containers. The lot number is required for all records, including reports on the ammunition condition and functioning and on any accidents in which the ammunition is involved. To ensure uniform functioning, all the components in any one lot are manufactured under conditions as nearly identical as practicable. When semifixed ammunition is fired, successive rounds should be of the same lot number so that maximum accuracy is obtained. When separate-loading ammunition is fired, successive rounds should consist of projectiles of the same lot number, propelling charges of the same lot number, fuzes of the same lot number, and primers of the same lot number.

d. National Stock Numbers and Department of Defense Ammunition Code. National stock numbers (for example, NSN 1320-00-529-7331) have replaced the old Federal stock numbers (FSNs), the old ammunition identification codes (AIC), and ordnance stock numbers. Each item of supply has a different national stock number. The first four digits of a national stock number are always the Federal supply classification (FSC) to which the item belongs. The next two digits identify the country of origin. Continental United States, for example, uses 00 and 01. Some of the other NATO countries use their assigned digits, such as 12 for Germany, 15 for Italy, and 21 for Canada to mention just a few. The next seven digits constitute the national item identification number (NHN). The dash between the third and fourth digits of the NIIN serves to reduce errors in transmitting. Each item has a different NIIN. A Department of Defense identification code (DODIC) is added as a suffix to the national stock number; for example, 1320-00-529-7331 (D544). The Department of Defense ammunition code (DODAC) is made up of eight characters--the four-character FSC code number and the DODIC. For example, 1320-D544, a typical DODAC, consists of FSC class 1320 and DODIC D544, which identifies a 155-mm HE projectile M107, and the NSN 1320-00-529-7331 indicates that the projectiles are packed eight per wooden pallet. The same DODIC suffixed to more than one NSN indicates items that are interchangeable. (See Appendix N.)

10-4. CARE AND HANDLING OF AMMUNITION

a. If ammunition is to function properly, it must be handled properly. Some of the basic principles of proper handling are listed below:

(1) Never tumble, drag, throw, or drop individual projectiles or boxes of projectiles.

(2) Do not allow smoking, open flames, or other fire hazards around ammunition storage areas.

(3) Inspect each round before it is loaded for firing. Dirty ammunition can damage the weapon, cause the breech not to close, or affect the accuracy of the round.

(4) Keep the ammunition dry and cool.

(5) Never make unauthorized alterations or mix components of one lot with another.

(6) If a round has been rammed and then must be extracted, return it to the battalion ammunition section. The rotating band or the fuze may be damaged and should not be fired.

(7) Leave the eyebolt lifting plug or closing plug screwed into the fuze well until the round is to be fuzed.

b. Care and handling of projectiles, fuzes, propelling charges, flash reducers, primers, and cartridge cases are discussed in paragraphs 10-5 through 10-10.

10-5. PROJECTILES

a. Projectiles must be inspected to ensure the following conditions:

(1) There is no leakage of the contents.

(2) The projectile is correctly assembled.

(3) The rotating band is in proper condition. If the rotating band is stained or discolored, that minor deficiency can be removed with fine sandpaper or steel wool. Projectiles with rotating bands which have minor dents or cuts can be fired. However, if dents or cuts go through the band, the round should be rejected by the using unit. The grommets must be secured and tight to prevent nicks and scarring of the rotating band or obturation band.

b. Most HE projectiles issued for use with proximity VT fazes are standard projectiles with deep fuze cavities to accommodate the longer VT fuze. Each of these projectiles is issued with a removable supplementary charge so that the projectile may be used with an impact, a mechanical time or a long intrusion (VT) fuze. The supplementary charge is removed only when the projectile is used with a long intrusion VT fuze. It must be in place when the projectile is used with a mechanical time fuze, impact fuze, or short intrusion VT fuze.

CAUTION
Do not try to remove the supplementary charge by any means other than the lifting loop. If the charge cannot be removed by the lifting loop, the round may be disposed of or fired with an impact or an MTSQ fuze. The deep cavity may be lined with a paper tube and bottom cup, which help support the high-explosive filler. This lining should not be removed at any time.

c. Because of their contents, toxic chemical and the WP shells require special handling and storage.

(1) Chemical rounds.

(a) When toxic chemicals are being fired, all personnel in the area should wear protective masks and anyone handling the shell should wear gloves.

(b) An ample supply of decontaminating agents should be available in case they are needed.

(c) If possible, these shells should be stored away from other types of ammunition and downwind of the battery area.

(2) White phosphorus. WP rounds (except for the M825 and M825A1) should be stored upright on their base at all times. The filler of these rounds will melt at a temperature of 111.4F. As a result, the filler shifts and the ballistic characteristics of the rounds change. The WP shell should be in an area free of any combustible materials and away from other ammunition if possible. (This also applies to the M825 projectiles.)

10-6. FUZES

a. The specific fuzes available for each weapon are discussed in the technical manual for the weapon.

b. Fuzes are sensitive to shock and must be handled with care.

c. Before fuzing a round, inspect the threads of the fuze and fuze well for cleanliness and serviceability.

d. The fuze should be screwed into the fuze well slowly until flush with the nose of the projectile. Using the M16 or M18 fuze wrench (as appropriate), back the fuze up one-quarter turn, then snap the fuze wrench back to secure the fuze.

e. After tightening the fuze, ensure that there is no gap between the nose of the projectile and the fuze. If a gap exists, remove the fuze from the projectile and segregate both from the ammunition. Premature detonation may occur if a fuze is not properly seated.

f. A projectile fuzed with a time fuze should not be lifted with a hand around the fuze. A slip of the hand might change the fuze setting.

g. Normally, fuzes containing superquick elements should not be used during rainstorms or hailstorms. They may detonate if struck by rain or hail. However, a new rain insensitive fuze, M739A1, has been developed and is available to be fired through storms with reduced possibility of premature functioning.

Note: Units must be aware of the ammunition restrictions that apply to their caliber of weapons. Restrictions are in the technical manual for the weapon.

h. To prevent the accidental functioning of the point-detonating elements of fuzes M564 and M548, the fuzes must not be dropped, rolled, or struck under any circumstances. Special care must be taken to ensure that a fuzed round does not strike the breech of a weapon during loading.

i. Any mechanical time fuze that is set and not fired must be reset to SAFE; and the safety wires (if applicable) must be replaced before the fuze is repacked in the original carton.

Note: Never fire a projectile without a fuze or with a fuze that is not authorized for that projectile.

10-7. PROPELLING CHARGES

a. Procedures for preparing and verifying propelling charges are published in respective weapon technical manuals. These procedures are safe, simple, and easy to train.

CAUTION
When firing multiple-round missions, the possibility of firing an incorrect charge is greater than when firing single-round missions because of increased tempo and because sections are rarely allowed to fire multiple-round missions during training. Procedures in the weapon technical manual always must be used.

b. Propelling charges, or powder, like other components of ammunition, must be kept cool and dry. Powder containers must be closed tight to keep moisture out.

c. Propellant bags must be firm, clean, and well laced or tied; and the increments must be inserted in the proper sequence.

d. Propellant must be inspected before the charge is prepared. The following are examples of things to check:

  • Missing increments, extra increments and/or incorrect sequencing (order) of increments.
  • Increment bags. Bags must not be damaged to the extent that black powder or propellant spills out.
  • Rotting (chemical odor).
  • The red igniter pad on the base of the base charge (155-mm propelling charges).

e. Do not fire unused powder increments. They should be removed to some storage area (commonly called a powder pit) preferably 30 to 40 feet from the nearest weapon, until they can be burned or otherwise disposed of. The procedures for burning powder are discussed below:

(1) For safety, select a burning site at least 200 feet from grass and loose debris as well as personnel and equipment.

(2) Determine the direction of the wind.

(3) Place charge increments in a single layer row not more than 12 inches wide.

(4) Arrange the row so that the powder will burn into the wind (Figure 10-3).

(5) Lay a train of combustible material about 15 feet long, perpendicular to, and at the downwind end of the row of charge increments. Light this train at the end farthest from the increments (Figure 10-3).

f. Burning powder creates a very large flash and a lot of smoke. In a tactical environment, the platoon leader must ensure that burning powder does not compromise the camouflage and concealment effort.

10-8. FLASH REDUCERS

a. For some propellants, separate flash reducers containing black powder and potassium sulfate must be used to reduce flash at night. The flash reducers speed up the combustion of unburned propellant gases, which helps prevent excessive muzzle blast.

b. Flash reducers absorb moisture readily, so they must be kept dry. Keep them off of damp ground and sealed in their containers until needed for use.

c. Destroy flash reducers as shown in Figure 10-3. Flash reducers the highly flammable. It is critical that they be disposed of properly to prevent injury.

d. The M119A2 charge 7 red bag propellent for 155 mm is manufactured with flash reducers attached. Do not remove these from the propelling charge.

10-9. PRIMERS

a. Primers are sensitive to both shock and moisture. Primers for separate-loading ammunition should be kept away from the propellant bags and left in their sealed containers until needed.

Note: Older series propellants may contain the MK4A2 primer. This primer is not authorized to be fired with any howitzer currently in use. Ensure that these primers are not fired and are turned in to the ammunition section.

b. Primers for semifixed ammunition are attached to the base of the cartridge case. The best way to protect them is to leave them covered with a fiber container cap until needed.

c. Before use, inspect all primers for signs of corrosion. If a seal has been broken, it is very likely that the primer has been affected by moisture and should be turned in.

10-10. CARTRIDGE CASES

a. The cartridge case of semifixed ammunition should be checked for corrosion. Light brown staining is normal oxidation; but black, green, yellow, or white stains mean heavy corrosion, which must be cleaned off as soon as possible (see Figure 10-4).

b. Cartridges must be checked for cracks, bulges, and burs.

c. The primer must be flush with the base of the cartridge. If it sticks out too far, it is dangerous. If it sits in too far, the round will not fire. (See Figure 10-5).

10-11. SEGREGATION OF AMMUNITION LOTS

a. Different lots of propellant burn at different rates and give different effects in the target area. For this reason, the registration corrections derived from one lot do not necessarily apply to another lot. Ammunition must be segregated by lot.

b. The FDC designates the lot of ammunition to be fired for each mission (or it is standardized). Therefore, the lot designator should be prominently displayed for each stack of ammunition.

c. Whether stored in the field, on vehicles, or at an ammunition supply point (ASP), different lots of ammunition must be conspicuously marked.

10-12. FIELD STORAGE OF AMMUNITION

a. The four greatest hazards to ammunition in the battery area are weather, enemy fire, improper handling, and careless smokers. Regardless of the method of storage, these hazards must be considered. Specific storage techniques are discussed later, but here are some general considerations:

(1) Stack ammunition by type, lot number, and weight zone (Figure 10-6).

(2) If ammunition is being stored on the ground, use good strong dunnage at least 6 inches high under each stack (Figure 10-7).

(3) Keep the ammunition dry and out of direct sunlight by storing it in a vehicle or covering it with a tarpaulin. Be sure adequate ventilation is provided (Figure 10-8).

(4) Provide ammunition, if off-loaded, as much protection from enemy indirect fires as time and available materials allow. If sandbags are used for protection, keep the walls at least 6 inches from the stacks and the roof at least 18 inches from the stacks to ensure proper ventilation.

b. Particular attention must be paid to ammunition temperature. Most ammunition components can be stored at temperatures as low as -80 F for periods of not more than 3 days and as high as +160 F for periods of not more than 4 hours per day. An increase in malfunctions may be experienced with some VT fuzes when the temperature is below 0 or above 120 F. Powder temperature affects the muzzle velocity of a fired round and is a matter of frequent concern to the FDC. At least two howitzer sections should be designated to keep track of the powder temperature. A powder thermometer is inserted into the top powder increment in the canister, and care must be taken to ensure the thermometer does not touch metal.

Note: Cannon sections must be careful not to fire the powder thermometer.

c. Only enough ammunition to meet current needs should be prepared for firing.

10-13. STORAGE AND TRANSPORTATION TECHNIQUES

a. In SP units, the M992 combat ammunition tracked vehicle is the companion vehicle to the howitzer. It serves as an area from which to service the weapon as well as a storage area for ammunition. This vehicle should be positioned with its howitzer and replenished in the battery area by the ammunition section. Ammunition should be left in pallets until needed for use.

Note: Be sure pallets are adequately cribbed and secured to prevent them from shifting during movement.

b. To increase the ammunition-carrying capability of cannon batteries, additional M332 ammunition trailers are authorized in the TOE. Although mobility may be degraded somewhat, an M332 trailer should be pulled by each of the ammunition vehicles currently shown in various TOEs. These are the M992 and the 2½-and 5-ton trucks. These 1½-ton trailers can--

  • Increase organic hauling capability,
  • Facilitate resupply and backhaul operations, and
  • Permit ammunition component segregation (to reduce the battery's vulnerability to counterfire).

c. In towed units, the prime mover, loaded with ammunition, should be positioned near the howitzer. Ammunition should be left loaded until it is prepared for firing. Other ammunition is stored on the battery ammunition section vehicles, or at a battery ammunition dump. The establishment of a battery ammunition dump is a matter of command decision, because it seriously impairs the mobility of the battery.

d. Appendix E provides the load plan for the M925 5-ton truck for M198 units.

e. The M992A1 CATV has specific storage locations for ammunition components depicted in its operator manual (TM 9-2350-267-10).

f. The artillery uses the 11 ton heavy expanded-mobility tactical truck (HEMTT), heavy expanded-mobility ammunition trailer (HEMATT), and the palletized load system (PLS) for transporting large quantities of ammunition.

10-14. ACCIDENTS

Generally, firing accidents are serious, so all supervisory personnel should know the immediate action to be taken.

a. If the ammunition or equipment presents further danger, move all personnel out of the area.

b. Do not change any settings on, or modify the position of, the weapon in any way until an investigation has been completed.

c. Record the lot number of the ammunition involved in the accident or malfunction, and report it to the battalion ammunition officer. If there is good reason to suspect a particular lot of ammunition, its use should be suspended.

d. If it is suspected that the propellant was ignited with no recoil of the tube, misfire procedures must follow. Perhaps no projectile was loaded and the propellant is still burning.

10-15. MISFIRE PROCEDURES

Misfires do occur. When they do, there are certain actions that must be taken within specific time limits. For that reason, personnel must be thoroughly familiar with the misfire procedures for their weapon system. These procedures are in AR 75-1 and weapons technical manual for the appropriate weapons.

10-16. TRAINING

a. Traditionally, ammunition training has been a weak area. Cannoneers seldom practice setting time fuzes or cutting propellant charges until the battery goes to the field to conduct live firing. There are several training extension course (TEC) lessons on ammunition to enhance individual training. Also, your Training and Audiovisual Support Centers (TASCs) have a wide selection of ammunition training materials.

b. Collective training is enhanced by using training rounds, which are available through the local TASC. New training rounds are constantly introduced into the training aids inventory. These rounds are designed to train the entire howitzer crew--from loading ammunition to setting fuzes, cutting charges, loading, and firing. Keep an up-to-date TASC catalog, and take advantage of these devices.

10-17. AMMUNITION PLANNING GUIDE

Tables 10-2 through 10-4, give information on ammunition available for various FA weapons. (Figure 10-9 provides a list of acronyms and abbreviations for Tables 10-2 through 10-4.)




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