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Ammunition, Fuze and
Projectile Definitions

& Ammunition Identification

  • AA - Anti-Aircraft.
  • AAC - Anti-Aircraft Common.
  • AHEAD - Advanced Hit Efficiency And Destruction.
  • Amatol - An explosive mixture of ammonium nitrate and TNT.
  • Ammunition Identification
    Ammunition is identified by markings and color-coding on the items themselves, the containers, and the packing boxes. The markings and standard nomenclature of each item, together with the lot number, FSC, NSN, DODIC, and DODAC, completely identify each item and are used to maintain accountable records. This appendix gives a basic explanation of markings and color-coding. Because color-coding is a more ready means of identification, it is given greater emphasis here.
  • AP - Armor Piercing.  Projectile for use against heavily armored targets.  Very little explosive within the shell, as it must be almost solid in order to penetrate through armor plate.  The USN has designated all capped armor piercing projectiles as AP since the early 1900s.  See "APC" below.
  • APC or CAP - Armor Piercing Capped or (rarely used) Capped Armor Piercing.  Most AP shells have a cap fitted over the nose which is intended to exert a high initial force on the face of the armor.  In addition, a ballistic cap is usually fitted over the AP Cap to provide a more streamlined shape for better aerodynamic characteristics.  See "Cap" below.
  • APDS - Armor Piercing Discarding Sabot.
  • APFSDS - Armor Piercing Fin-Stabilized Discarding Sabot.
  • API, AP-I, APT or AP-T - Armor Piercing Projectiles that include a Tracer (Incendiary).
  • Arrow Shell - A fin-stabilized HE projectile.  In German, "Pfeilgeschoss."
  • Bag Ammunition - Ammunition in which silk or rayon bags are used to hold the propellant and the projectile is handled separately.  Propellant bags were manufactured from a special coarse silk known as "shallon" or "cartridge cloth."  This burned without leaving any smoldering residue in the barrel which would present a safety hazard when loading the subsequent round.  Rayon bags replaced silk ones in the USN after a serious propellant fire aboard USS South Dakota BB-57 in 1945 was traced to a spark generated when a bag was removed from its metallic container.
  • Ballistic Cap - Often called a "windshield," this is a covering on the nose of a projectile which is intended to provide a more streamlined shape for better aerodynamic - ballistic - characteristics.


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  • Ballistic Coefficient - Measure of the ability of a projectile to overcome air resistance.  Ballistic coefficient (BC) = SD / F, where SD is the sectional density of the projectile and F is a form factor for the shape of the projectile.  Sectional density is calculated from the mass (M) of the projectile divided by the square of its diameter.  The value of F decreases with as the pointedness of the projectile increases.  A projectile shaped like a sphere would have the highest F value while one in the shape of a long needle would have the lowest F value.
  • Ballistic Conditions - Conditions which affect the motion of a projectile in the bore and through the atmosphere, including muzzle velocity, weight of projectile, size and shape of projectile, rotation of the earth, density of the air, elasticity of the air and the wind.
  • Ballistic Curve - Actual path or trajectory of a projectile.
  • Ballistic Density - Computed constant air density that would have the same total effect on a projectile during its flight as the varying densities actually encountered.
  • Ballistic Efficiency - Ability of a projectile to overcome the resistance of the air.  Ballistic efficiency depends chiefly on the weight, diameter and shape of the projectile.
  • Ballistic Length or Head Length - The length of the projectile's nose.  See "crh" below.
  • Ballistic Limit - Velocity at which a given type of projectile will perforate a given thickness and type of armor plate at a specified obliquity.  Also see "Armor Penetration Definitions," in Miscellaneous Definitions.
  • Ballistics, Internal, Intermediate, External and Terminal - Internal Ballistics is the study of what the projectile does from the moment of firing up until it leaves the muzzle of the weapon.  Intermediate Ballistics is the study of the projectile between the time it exits the muzzle until it overtakes the muzzle shock waves and enters normal atmosphere.  External Ballistics is the study of what the projectile does as it travels from the end of the intermediate stage to the target.  Terminal Ballistics is the study of what the projectile does as it strikes the target.
  • Balloting - The bounding from side to side of a projectile in the bore of a gun.
  • Base - The after end of the projectile, usually described as that portion between the driving bands and the bottom of the projectile.
  • Base Bleed - This is a unit on the base of a projectile that generates a gas, something like a tracer.  What this does is fill in the vacuum that is created behind a rapidly moving projectile and thus greatly reduces the amount of drag acting on the projectile.  The gas also acts like a long tail, making the projectile more stable in flight.  The end result of these actions is an increase in range and accuracy.
  • Base Cover - A metal cover that is crimped, caulked or welded to the base of a projectile.  This cover prevents the propellant gasses from coming in contact with the explosive filler of the projectile through possible flaws in the metal of the base.
  • Base Plug - A removable seal in the base of a shell which holds in the explosive filler.
  • Belt, Ammunition - Multiple rounds of ammunition that are held together by a strip of fabric or metal.  Used most often for feeding ammunition to automatic weapons.  Ammunition belts may be disintegrating (linked), non-disintegrating or continuous loop.
  • Blind Shell - A shell containing no explosives or one having its fuzing disabled so that it does not explode.  Often used for proof tests against armor plate.
  • BL&P - Blind Loaded & Plugged.  Same as a Blind Shell.
  • Boat Tailing - Tapering that part of the projectile behind the driving band to reduce air resistance, especially at low velocities.  This type of design gives a projectile greater range but tends to increase wear on the gun barrel.  It was long thought that boat tailing caused greater dispersion in the impact pattern, but a study published in 1978 by the US Army's Ballistic Research Lab showed that the opposite was true.
  • Body - The cylindrical portion of the projectile between the bourrelet and the driving bands.  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.
  • Booster - An explosive of special character, usually of high strength and high detonating velocity, generally used in small quantities to improve the performance of another explosive, the latter constituting the major portion of the charge and made up of a less sensitive explosive.  Also see "Gaine."
  • Bourrelet - Finely machined band or ring of metal just behind the ogive of a projectile, designed to support the front portion of the projectile by riding the lands as the projectile travels through the bore of a gun.  Only the bourrelet and the driving bands of a projectile actually touch the rifling.  Some projectiles have a second bourrelet located between the base of the projectile and the driving bands.  This second bourrelet acts to reduce the tip-off angle by keeping the projectile body centered in the gun barrel after the forward bourrelet has exited the muzzle.
  • Brisance and Brisant - Brisance is the measure of how rapidly an explosive develops its maximum pressure.  A brisant explosive is one in which the maximum pressure is attained so rapidly that the effect is to shatter any material in contact with it and all surrounding material.
  • Bursting Charge - The explosive within a shell.  Known simply as "Burster."  Some of the more well-known:
  • Black Powder or Gunpowder - Used as the burster in most shells prior to the early years of the twentieth century.  A common procedure was to fill the shell cavity with gunpowder or to put the explosive into a loosely-restrained bag at the base of the projectile.  In this latter variation, when the projectile struck the target it was intended that the bag would be torn loose from its restraints and flung forward against the interior of the shell.  In either variation, these projectiles relied upon impact shock to set off the burster.  About as reliable as it sounds, hence the intensive search for better explosives, more reliable fuzing and the interest in the Zalinsky "Dynamite Gun" experiments.

  • Gun Cotton - See "Propellants" below.
  • Explosive D - USN burster made from Ammonium Picrate, a salt formed from picric acid.  Adopted prior to World War I, this explosive is very insensitive to shock, giving it a high margin of safety.  Used for both AP and HC (HE) projectiles.
  • Lyddite - British Picric Acid, trinitrophenol.  Prior to 1908, the British used gunpowder as the burster for both AP and Common shells, but after that date Lyddite came into use for HE projectiles.  In 1909, the Royal Navy began experimenting with APC using Lyddite as the burster and began introducing them into service the following year, even though testing had shown that this filling was more sensitive to shock than gunpowder and thus prone to explode prematurely before the shell had a chance to penetrate almost any thickness of armor plate.

  • Melanite - French picric acid, roughly equivalent to Lyddite.
  • Shellite - Adopted just after the end of World War I, this British burster was a less sensitive picric acid mixture, containing a mixture of 70% Lyddite and 30% of the much weaker, insensitive explosive dinitrophenol.
  • Shimose - Japanese picric acid, roughly equivalent to Lyddite.
  • TNA - Japanese tri-nitro-aniso, designated as Type 91 bakuyaku (Model 1931 Explosive).  This was a more stable burster than Shimose.
  • TNT - Tri-nitro-toulene.  Few, if any, nations used pure TNT.  Instead, this was usually mixed with a desensitizer, such as beeswax.  For example, German shells of World War II used a beeswax mixture with the concentration of beeswax decreasing from the head to the base of the cavity.

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  • Bursting Charge Power - The following approximations of explosive power may be used using TNT = 1.00 as a reference point.

  1. Before and during World War I
    • Black powder = 0.33 to 0.50
    • Guncotton = 0.50
    • Picric Acid (British Lyddite, French Melanite and Japanese Shimose) = about 1.05 to 1.10
  2. After World War I
    • German and Italian TNT = 1.00
    • British Shellite = 0.96
    • Japanese TNA = 1.05
    • USA Explosive D = 0.95
  3. Other Explosives (torpedo warheads, mines, depth charges)
    • Amatol (80/20) = 1.24
    • DD (Dinitronaphthalene/Dinitrophenol 60/40) = 0.82
    • PETN = 2.21
    • MDN (Melinite/Dinitronaphthalene 80/20) = 0.88
    • RDX = 1.94
    • Tetryl = 1.39
    • Torpex = 1.50
    • German SW types = about 1.07
    • Japanese Type 97 (TNT/hexanitrodiphenylamine 60/40) = about 1.07

Two rules of thumb:
1) The effect of the burster may be taken as being proportional to the square root of the weight of the bursting charge.
2) For the same basic shell design, the size of the bursting charge is proportional to the cube of the bore size.

  • Cap - Hardened steel nose piece of an APC projectile.  Introduced by Russia and America in 1894 and adopted by the British Royal Navy in 1903.  See illustrations on this page.  The cap serves the following purposes:

    1) It is shaped so as to increase the biting angle; that is, the angle at which the projectile will penetrate rather than ricocheting.
    2) It spreads the shock of impact over the periphery of the nose instead of allowing the initial contact to batter the nose tip.
    3) It pre-stresses the armor plate upon impact before the cap shatters away.  This means that the shell body sees a weakened plate.
  • Cannelure - Means a ring-like groove or a groove encircling a cylinder.  These have the following uses in ammunition and weapons:

    1) On projectiles used in fixed ammunition:  The groove provides a means of securely crimping the cartridge case to the projectile.
    2) On armor-piercing bullets:  The groove is used to lock the jacket of an armor-piercing bullet to the core.
    3) In the rotating band of a projectile:  The groove lessens the resistance from the rifling as the projectile travels down the gun barrel.
    4) Around the base of a cartridge case:  The groove is where the extractor takes hold to eject the spent case.
    5) In the construction of British large-caliber, wire-wound weapons:  Cannelured rings were used to prevent "steel choke" problems.
  • Cartridge - For rifles and pistols, this is usually defined as being the term for a complete round of ammunition, including the projectile, cartridge case, propellant and primer.  For larger caliber weapons, especially those using separate ammunition, this term is usually applied to only the metallic propellant container.  See next definition.
  • Cartridge Case, Powder Case, Propellant Case or Casing - A metallic container for holding powder charges and usually includes a primer element.  This type of propellant container allows higher rates of fire and is less likely to catch fire in case of damage from a shell hit.  It is also less likely to suffer a flareback type of disaster caused by the smoldering remnants from the previous powder charge.  However, for larger caliber guns, it does require more complicated and heavier handling equipment than does bag ammunition.  Germany used a variation of this for their larger guns, where the propellant was divided in to two sections, a fore charge in a bag and a main charge in a cartridge case.  Also see "Fixed" and "Semi-Fixed."

  • Cartridge Case Size - Cartridge cases are usually designated by the diameter of the projectile they fire and by the overall length of the casing.  Letter suffixes indicate the type of casing.  For example, the famous Oerlikon 20 mm of World War II used 20 x 110RB casings.  This meant that the cartridge cases were for 20 mm projectiles, had an overall length of 110 mm and had a Rebated Rim.  It should be realized that this is an imprecise method of identifying casings, as it neglects body diameter and shape.  Most cartridge cases are of one of the following types:

  • Belted - Cartridge cases having a belt of metal above the extraction groove approximately the same diameter as the rim.  Denoted by the suffix B after the diameter and length values.
  • Rimless - Cartridge cases having an extraction groove with the base of the cartridge case being no wider than the rest of the cartridge case body.  This type of cartridge case does not have a suffix following the diameter and length values.
  • Rimmed - Cartridge cases having a rim at the base wider than the rest of the cartridge case and not having an extraction groove.  Denoted by the suffix R.
  • Semi-Rimmed - Cartridge cases that have a rim that is wider than the body of the casing with an extraction groove just above the rim.  Denoted by the suffix SR.
  • Rebated Rim - Cartridge cases whose bottom rim is smaller in diameter than the body of the cartridge case.  There is an extraction groove between the rim and the rest of the cartridge case body.  Denoted by the suffix RB.
  • Cartridge Case, Bottle-Necked - A cartridge case whose main body diameter is significantly larger than that of the projectile and has a short "neck" section which holds the projectile.  This design may be used with any of the above cartridge case types.  A bottle-neck cartridge case holds more propellant for a given length than will a non-bottle neck cartridge case.

  • Cartridge Case, Tapered - A cartridge case whose body diameter increases from the neck to the rim.  This type of cartridge case ejects easier from the firing chamber than does a "straight" walled cartridge case, as any backwards motion releases the entire cartridge case body from the walls of the firing chamber.  Most military ammunition manufactured today has at least some degree of taper.

  • Case Ammunition - Ammunition using a cartridge case to hold the propellant.  See "Fixed" and "Semi-Fixed" below.
  • Case Plug or Mouth Plug - The sealing device in the mouth of a cartridge case used for separate (semi-fixed) ammunition.  This may be of cork, plastic or cardboard.  The USN originally used a brass mouth cup to seal cartridge cases, but after one "boomeranged" back on board the transport SS Mongolia and killed two nurses in May 1917, cardboard ones were substituted.
  • CCAMS - Course-Corrected Anti-Missile Shell.

  • Charge or Powder Charge - The amount of propellant used in firing a weapon.

  • Common - Common projectiles were originally shells - which literally means a hollow container - filled with black powder and used for attacking lightly armored or unarmored vessels.  By the 1930s, this term was used by a few navies to describe any non-armor piercing shell.  By that time, the bursters were less sensitive explosives, such as TNT.  In the USN, Common projectiles of the 1920-1950 period did not have caps or hoods and were designed to penetrate approximately one-third of their caliber of armor.  See "Special Common" below.

    • CLGP - Cannon-Launched, Guided Projectile.  Long-range ballistic projectiles using terminal laser guidance developed during the 1970s for the USN's 5"/54 Mark 42 and 8"/55 Mark 71 guns.
    • CNF - Common, nose fuze.  British projectile designation.
    • CPBC - Common Pointed Ballistic Cap.  British designation for shells of 6" (15.2 cm) and larger for use against medium thicknesses of armor.  After 1946 this designation was changed to SAPBC - Semi-Armor Piercing Ballistic Cap.
    • CPC - Common Pointed Capped.  British designation for shells of 6" (15.2 cm) and larger for use against lightly armored targets.  Little armor penetration capability but large bursting charge.
    • crh - Caliber Radius Head.  The pointed head of a projectile is described in terms of its ballistic length and the radius of the curvature of its nose.  Larger numbers mean a more streamlined profile.  Properly, crh is shown as a dual number such as 3/4crh, with the first number indicating the ballistic length and the second number indicating the radius of the curvature, but it is often abbreviated to a single number such as 4crh.  In the sketch at the right, the dotted line between Points A and B is the "shoulder" which is the start point of the nose and the distance between these points is the caliber of the projectile.  In this sketch, the radius of the curvature is from Point A to Point E and is four times the caliber of the projectile.  The vertical distance between Points C and D is the ballistic length and is the most important factor in the design of a shell for stability in flight.  In this sketch, the ballistic length is 4, as Point E is on the same plane as Points A and B.  From these numbers, this projectile would properly be described as 4/4crh but this would normally be abbreviated to just 4crh.  Shells of this general shape are described as being "ogival headed" and have superior ballistic performance.  As can easily be imagined, a 6crh shell is more pointed and streamlined than is a 4crh shell.  When crh is described as 5/10crh it means that the radius is 10 calibers long but the ballistic length is that of a 5crh shell.  When a projectile is described as 5/crh it means that it has a ballistic length of 5 and its nose shape is conical (infinite radius), not ogival.  Most UN projectiles had secant ogive ballistic nose shapes which were somewhat more conical than a simple tangent ogive (smooth merging joint with cylindrical lower-body side) and gave them a distinct "shoulder" where the nose met the cylindrical side of the lower body).  This shape has slightly reduced air friction compared to a tangent ogive nose of the same length above the cylindrical body.  For further information, see the essay Calculating crh on the Technical Board.

  • Dark Tracer and Dark Ignition Tracer - Tracers that do not ignite until the projectile is 100 to 400 yards (90 to 370 m) from the muzzle.  The USN developed these tracers late during World War II for their 20 mm and 40 mm automatic weapons.  These late igniting tracers eliminated the blinding effect on gunners at night and made the origin of tracer fire harder to determine.

  • DART - Driven Ammunition Reduced Time of flight.  Sub-caliber guided projectile with canard control, intended to improve the performance of the OTO-Melara 76/62 gun in the antimissile role.  Uses a radio-frequency beam rider guidance system which utilizes the firing ship's tracking radar.

  • DBX - Depth Bomb Explosive.  USN solid explosive developed during World War II to replace Torpex and used mainly for depth charges.  It is a mixture of TNT, cyclonite, ammonium nitrate and aluminum.

  • Density Factor - The weight of a projectile measured in pounds divided by the cube of its caliber measured in inches.  For example, the USN 16" (40.64 cm) AP Mark 8 weighed 2,700 lbs. (1,224.7 kg).  The density factor of this projectile is thus 2,700 / 163 = 0.659.

  • Detonator - An explosive device used to set off a larger explosive, such as a blasting cap used to set off TNT.

  • Distance Piece - This is usually a rectangular cardboard piece folded into a triangular shape and placed into the cartridge case between the wad and the case closure plug or projectile.  The distance piece is used to hold the propellant firmly in place when the amount of propellant does not completely fill the cartridge case.  Distance pieces are generally used in fixed and semi-fixed ammunition for 40 mm and larger projectiles.

  • DPICM - Dual Purpose Improved Conventional Munition.  A submunition carried as payload in projectiles such as the USN 5" (12.7 cm) Cargo Round.  "Dual Purpose" refers to the munition having both anti-personnel and anti-armor capabilities.

  • Drag - The effect of air resistance on a projectile.  Drag (D) = f(V/A) * K * � * P * Di2 * V2, where f(V/A) is a coefficient related to the ratio of the velocity of the projectile to the velocity of sound in the medium through which it travels.  Sound through air at 68�F (20�C) at sea level travels at 1,128.6 fps (344 mps).  K is a constant for the shape of the projectile.  � is a constant for yaw (deviation from linear flight).  P is the density of the medium, Di is the diameter (caliber) of the projectile, and V the velocity.  The degree to which a projectile is slowed by drag is called retardation (r) given by the formula:  r = D / M, where M is the mass of the projectile.  Drag is also influenced by the spin of the projectile.  The faster the spin, the less likely a projectile will "yaw" or turn sideways and tumble.  However, if the projectile spins too fast, it will not "turn over" at the top of its trajectory (apogee) and so will not strike the target nose-first.

  • Driving Band - A raised ring of soft metal encircling a projectile.  Also known as "rotating band."  These are made of copper, brass or soft steel.  USN driving bands on large caliber projectiles consisted of 97.5% copper and 2.5% nickel.  There may be more than one band on each projectile.  The bands engage the rifling in the gun barrel, causing the projectile to spin as it travels through the barrel.  They also provide a tight seal so that the propellant gases do not escape past the projectile as it travels down the barrel.  An "augmented driving band" or "augmented rotating band" is a slightly thicker strip of metal used when the rifling in the gun barrel has been worn down.  See "Rifling" above.

  • Eccentricity - Distance from the geometric center line of a projectile to the center of gravity of the


  • ERGM - Extended Range Guided Munition.  Effectively missiles fired from a gun barrel, these special projectiles are currently under development for the US Navy for the 5"/62 Mark 45 Mod 4 and 155 mm AGS gun systems.

  • F or FF - Form Factor.  A value used for ballistic calculations.  See "Ballistic Coefficient" above.

  • FAP - Frangible Armor Piercing.  FAP is usually a projectile with a tungsten alloy core which breaks up into multiple fragments when it strikes a hard surface.  The FAP projectile combines armor penetration, blast effects and incendiary action, all from an inert projectile that has no more logistical safety problems than a training round.

  • FAPDS - Fragmented Armor Piercing Discarding Sabot.

  • Fixed Ammunition - Ammunition in which the cartridge case is attached to the projectile, similar to a pistol bullet.  This type is usually limited to smaller weapons as the weight becomes prohibitive for hand-worked guns as the caliber increases past about 4 inches (10.2 cm).  On my datapages for guns firing this type of ammunition, the value given for "Weight of Complete Round" refers to the total of the individual weights of the projectile, cartridge case, propellant and igniter all added together.  The weight of the projectile itself is given separately if available.  Also see "Bag" above and "Semi-fixed/Separate" below.


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  • Flechette - A small fin-stabilized projectile.  Usually used in large numbers inside of a single carrier projectile.
  • Fuze - An overview of fuzes used since the 1900s.

    • Boresafe Fuze - Type of fuze having an interrupter in the explosive train that prevents the fuze from functioning until after the projectile has cleared the muzzle of the weapon.  A "non-boresafe fuze" does not have this feature.

    • Base Fuze - Fuze located at the bottom end or base of the shell.  This is the most common location for AP and SAP projectiles as it avoids weakening the nose of the shell and protects the fuze from damage as the projectile passes through armor.  Some HE/HC shells have both nose and base fuzes as this increases the chances of the shell detonating under differing conditions.

    • Contact Fuze - A fuze initiated only after it impacts the target.  There are two general types of contact fuzes, "delay" and "super quick" both further defined below.

    • CCF - Course Correcting Fuze.  A smart fuze that uses aerodynamic fins together with GPS in order to steer an otherwise ordinary ballistic projectile.

    • Delay Fuze - A contact fuze that detonates the projectile only after it has impacted and penetrated some distance into the target.  A "short delay" means that the fuze initiates detonation within a few thousandths (0.00X) of a second after impact.  For naval guns, short delays are generally used for HE/HC rounds while longer delays are used for AP rounds.  Some delay fuzes have a ring or dial which allows adjustment of the delay time.  For AP projectiles, it is desirable to have the shell detonate only after it has penetrated past the armor plating, thus letting it get into the "vitals" of the target ship's interior.  For most AP rounds of the twentieth century, this delay was usually about 0.030 to 0.070 seconds, roughly equivalent to 35 to 80 feet (10 to 30 m) of travel.  In addition, some thickness of armor plate was needed to initiate the fuze action.  For example, the USN required that for hits of 0 degrees obliquity that the AP fuze would not activate unless the armor plate was at least 1 inch (2.54 cm) thick.

    • Nose Fuze - Fuze is located at the top point of the shell.  This is the most common location for HC and HE shells as the fuzes can be set to allow little or no time delay and thus detonate the bursting charge immediately upon impact.  Many nose fuzes have "auxiliary detonating" fuzes behind them.  These provide a heavier shock which actually detonates the bursting charge.  Auxiliary fuzes also act as a safety feature by preventing the projectiles from exploding should the nose fuze be accidentally actuated prior to the arming of the auxiliary detonating fuze.

    • Proximity Fuze - Fuze containing a simple radar that can detect the nearness (proximity) of a target.  Also called "influence fuze."  First used in World War II on USN 5 in (12.7 cm) AA shells which were called "VT Fuzed" where VT stood for "Variable Time" (it appears to be a myth that "VT" was a reference to "Section T," the BuOrd development team for proximity fuzes).  These fuzes are also widely used for anti-personnel rounds for land artillery as they eliminate the need to accurately set a time fuze to explode the projectile at a fixed distance above the target.  During World War II, the US Army called these "posit" or "pozit" fuzes.  This term meant that the proximity fuze allowed the shell to detonate at the most effective height or "position" above the ground.  Since World War II, fuzes small enough to fit onto 40 mm AA rounds have been developed.  The modern British versions of proximity fuzes are called TTB - Target Triggered Burst.

    • Super Quick Fuze or Instantaneous Fuze - A contact fuze designed to detonate the projectile before it has penetrated any distance into the target.  Super quick fuzes are commonly used on anti-aircraft rounds that are designed to shred the outer airframe.

    • Time Fuze - Fuze has an adjustable mechanism - usually an incremented dial or "ring" or, in more modern fuzes, an electronic timer - which is used to set a delay time.  Commonly used for AA projectiles, smoke and illumination rounds, this type of fuze is used to set the time between when the shell is fired and when it detonates.

  • Fuze Setter
    1) A machine located on or near the gun platform that is used to set time fuzes, usually for AA projectiles.
    2) A gun crewman whose job it is to either operate the Fuze Setter machine or, by using a wrench or similar tool, to manually set projectile time fuzes.

  • Fuze Setting in the Hoist - Hoist fuze setting was first successfully accomplished by the USN with its 5"/38 (12.7 cm) when coupled with the Mark 37 GFCS.  In this system, the projectiles were inserted nose down into a cup on an endless chain hoist that led from the handling room directly below the mount up to the gun breeches.  As the projectile traveled up the hoist, a pawl in the cup, driven by the GFCS, would engage a lug on the projectile's time fuze ring.  The cup rotated the pawl so as to set the time fuze.  The time fuze setting was automatically and continually adjusted during the hoist as the firing solution changed.  Loaders were trained to wait until the last possible moment before removing a projectile and placing it on the loading tray so as to get the best possible time adjustment.

  • Fuze Setting at the Muzzle - Muzzle fuze setting is normally done by induction.  The fuze setter itself consists of a ring around the muzzle that generates a weak pulsed-electromagnetic field.  As the fuze passes through the ring, it senses this data signal and sets itself accordingly.

  • Gaine (Booster) - An explosive container detonated by the fuze and which in turn detonates the bursting charge.

  • Grain
    1) A measure of weight used in the UK and USA for small propellant charges and for the weight of small caliber bullets.  1 pound = 7,000 grains.  1 gram = 15.432 grains.
    2) An individual particle of propellant.  A degressive or regressive grain is one whose total burning surface area decreases as it burns.  Propellant grains formed in balls, cords, pellets and thin sheets burn degressively.  Degressive grains are generally used in weapons having a short barrel length.  A neutral burning grain is one whose total burning surface remains approximately constant as it burns.  Single perforated grains and star perforations are examples of neutral burning grains.  Technically, grains formed in thick sheets or strips burn degressively, but the change in burning area is so small that they may be considered to be neutral burning.  A progressive grain is one whose total burning surface increases since it burns from both the inside and the outside at the same time.  Grains with multiple perforations and those in rosette shapes burn progressively.

  • Greenboy - Improved British AP projectile developed late in World War I.  The ballistic cap for these projectiles was painted green to distinguish them from older models, hence the nickname.  Following the failure of British AP projectiles to detonate properly during the 1915 Battle of Jutland (Skagerrak), the Royal Navy began an intensive effort to produce better versions.  These were introduced into service starting in 1918 and had a new delay-action base fuze patterned after the ones used on German 28 cm Psgr. APC projectiles.  Greenboys had better armor penetration abilities compared to the older models, thanks to an improved body and the new "Hadfield" hardened AP cap.

  • Grommet - Projectile cover used to protect the rotating band of projectiles during handling.  The grommet is removed before the projectile is fired.

  • HC - High Capacity.  A USN designation for projectiles intended for use against lightly armored targets.  Contains a relatively large amount of explosive as compared to an armor piercing or common projectile.  Burster was between 7.0% to 12.6% of total projectile weight.

  • HE - High Explosive or High Effect.  Same as HC.
  • Head Length - The length of the projectile's nose.  Same as "Ballistic Length."  See "crh" above.
  • HEI or HE-I - HE projectiles that include an Incendiary.
  • HE-I-SD - Self-destructing incendiary HE projectile.
  • HE-CVT - HE with a Controlled Variable Time (proximity) fuze.
  • HE-IR - HE with an infrared fuze.  These rounds use a passive IR fuze that operates only on the infrared spectrum detected in the exhaust gasses of jet and hot missile targets.  These fuzes are harder to jam than radar-type proximity fuzes.
  • HE-MOM - HE Multirole OTO Munitions.  OTO-Melara ammunition with proximity fuzing and tungsten cubes surrounding the bursting charge.
  • HE-PF-OM - HE Pre-Fragmented OTO Munition.
  • HE-PD - HE with a Point Detonating (contact) fuze.
  • HE/SD - Self-destructing HE projectile.
  • HET or HE-T - HE shell with a tracer.
  • HE-T/SD - Self-destructing HE-T shell.
  • HETF - British high explosive projectile with time fuze.
  • HE-VT - High Explosive with a Variable Time (proximity) fuze.
  • HMX - Cyclotetramethyenetetranitramine.  A white crystalline powder used as a high energy oxidizer in propellants and explosives.

  • Hood - Thin cap used on USN Special Common projectiles to attach the windshield to the projectile body.

  • Hygroscopic - Literally means "water seeking" and is used to describe a material that readily absorbs water (usually from the atmosphere).

  • Igniter or Igniter Patch - Bag ammunition charges have a small patch at one or both ends containing black powder (gunpowder).  This is used to set off the main propellant charge.  See "primer" below.

  • ILLUM or Illuminating - Commonly called "Star Shells," these projectiles are usually filled with magnesium and are used at night to light up (illuminate) the target.  Many use a parachute in order to slow their descent.

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  • ILLUM-MT - Illumination round with a Mechanical Time fuze.
  • K Shells - British term for projectiles using dye bags.  See "Splash Colors" below.
  • Lead Foil - A piece of lead foil is sometimes inserted at the top of the propellant in a cartridge case.  The lead foil aids in scouring away residue left from the driving bands or unburnt propellant.

  • Lifting Plug - Threaded eyebolt which fits into the fuze cavity (nose or base), permitting heavy shells to be handled by means of a winch.

  • Link - The part of an ammunition belt which joins the individual rounds together.  Usually, one link holds one round.  "Disintegrating Link" means that the links holding each individual round to the next round separate from each other and from the cartridge as each round is fired.

  • LRBA - Long Range Bombardment Ammunition.  USN munition developed as part of the "Gunfighter" program of the late 1960s.  These were unguided 5" (12.7 cm) projectiles enclosed in a sabot and fired from 8" (20.3 cm) gun barrels.  These sub-caliber projectiles had a maximum range of about 72,000 yards (66,000 m) and were successfully used against Viet Cong targets at 70,000 yards (64,000 m).

  • LRLAP - Long Range Land Attack Projectiles.  These are being developed as part of the AGS program.

  • Meplat - The flat or blunt area at the tip of a projectile.  Usually specified by its diameter.

  • MPDS - Missile Piercing Discarding Sabot.

  • MT - Mechanical Time.  Designation for Time Fuzes used by the US Navy.  See "Ring or Time Fuze" below.

  • NACO - Navy Cool.  A cooler-burning propellant currently in use by the US Navy.

  • NCT - Nitrocellulose Tubular.

  • Nitrated Cotton - A short-fibered cotton bleached and purified to the point where it is 90% pure cellulose.  This material forms the basis for nitrocellulose used in propellants.  See "Propellants" below.

  • Nose Plug - The Lifting Plug (see above) used for nose-fuzed projectiles.

  • Nutation - The aerodynamic, gyroscopic and inertial forces acting on a spinning projectile are in constant flux as it travels through the air.  As the various forces readjust themselves, the nose of the projectile describes a small arc around the axis of travel.  This motion is called "nutation" from the Greek word for "nodding," which is a good description of what the projectile actually does.

  • Obturator - In projectiles, this is a band, usually made of nylon, below the driving bands.  The band helps prevent propellant gasses from escaping past the projectile as it travels up the gun barrel.  Commonly described as the "Forward Obturator" or "Forward Located Slip Obturator" to distinguish it from the breech obturator.

  • Ogive - The curved area making up the nose of a projectile.  Usually defined as extending rearwards from the tip of the projectile's nose to the main cylindrical portion or bearing surface.  From an ordnance manual: "Often a convex solid of revolution generated by an arc of a circle whose center lies on the side of the axis of revolution opposite to the arc."  Whew, glad I found that out!  In layman's terms, the head of the projectile is usually bullet-shaped.  See "crh" above.

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  • Oxidizer - Reactive compound which gains electrons during an oxidation-reduction chemical reaction.  In propellants, this is the ingredient that provides oxygen for the burning process.

  • Palliser Projectile - Iron armor piercing shells of the mid to late 19th century which were hardened by casting the projectiles point downwards and forming the heads in an iron mold.  This process rapidly chilled the hot metal of the nose and made it intensely hard.  The remainder of the projectile mold was formed of sand, allowing the metal of the shell body to cool more slowly, making it tough but not brittle.  These shells were powder-filled, but did not use a fuze.  Instead, they relied upon the shock of striking the target to set off the burster.  These shells were effective against wrought iron armor, but shattered against steel armor.  Named after the inventor, Sir William Palliser.

  • PBX - Plastic Bonded Explosive.  A mixture of cyclonite, HMX, PETN and a plastic binder.  Has high mechanical strength, excellent chemical stability and is shock resistant.

  • PETN - Pentaerythritol tetranitrate.  Shock-sensitive material used in explosives, blasting caps and in some mono-propellants.

  • PFHE - Proximity Fuzed High Explosive.
  • Posit or Pozit Fuze - See "Fuzes" above.
  • Powder Bags - See Bag Ammunition, above.
  • Powder Grain - An individual unit of propellant.  Commonly used in the form of strips, cords (strings), hollow tubes (single perforation) or multi-perforated cylinders.  Cord grains have steadily decreasing burning surfaces.  Single perforated grains and strips have a practically constant burning surface.  Multi-perforated cylindrical grains have an increasing burning surface, since combustion proceeds from the outer diameter inward and from the perforations outward.  A propellant grain with a decreasing burning surface will tend to generate less propellant gas as it burns while a propellant grain with an increasing burning surface will tend to generate more propellant gas as it burns.

  • Pre-fragmented - A projectile, usually AA or anti-personel, that has been sectioned so as to break up into uniformly-sized pieces when the round detonates.

  • Primer - A device used to provide a flame for the purpose of setting fire to a propellant charge.  Also called an "igniter."  Primers are divided into two types, depending upon the type of ammunition used by the gun:  1) Case and 2) Lock.  Case primers, as their name implies, are used for guns firing case ammunition.  These are small containers of an explosive such as mercury fulminate that are installed into the base of the cartridge case.  Lock primers are used for bag guns and are inserted by hand into the firing lock of the gun.  Primers are also divided into three classes, depending upon the method of firing:  1) Percussion, 2) Electric and 3) Combination.  Percussion primers are fired by the mechanical impact of a firing pin.  Electric primers are fired by passing a current through a resistance element surrounded by an initiating mixture.  Combination primers may be fired by either of these methods, which allows for a mechanical backup if the electrical supply system to the gun fails.

  • Prismatic Powder - In 1860 General Thomas Jackson Rodman of the United States Army, realizing the advantages to be gained by increasing the propellant burn time, proposed the use of large grains of very dense black powder for this purpose.  As a result of his research, he also proposed that perforated grains be used in order that the burning surface of each grain might be increased as combustion proceeded.  The use of these grains gave a means of better regulating the ballistic action of black powders, and thus reduced undesirable items such as fluctuations in muzzle velocity.  Different grain forms were tried, such as spherohexagonal and various prismatic shapes, including the hexagonal prism with a single perforation.  The latter form was widely used in larger guns.  The use of such grains was the first notable advance in securing a powder which would burn progressively, that is, with increasing evolution of gases and heat.

  • Propellants - An overview of some of the more common propellants used by naval guns since the 1880s.

  • Single-Base, Double-Base and Composite Base Propellants - Propellants are classified into three types; single-base, double-base and composite.  Single base propellants are primarilly gelatinized nitrocellulose that do not contain an explosive ingredient such as nitroglycerin.  Double-base propellants are mainly compositions that are predominately nitrocellulose and nitroglycerin.  Composite propellants are compositions that contain mixtures of fuel and inorganic oxidants but do not contain a significant amount of nitrocellulose or nitroglycerin.  There are also combinations of composite and double-base propellants.

  • Ballistite - This is a double-base propellant for rockets.  It is composed of nitrocellulose and nitroglycerin, blended together with diphenylamine, which acts as a stabilizer.  This mixture burns with a considerable amount of flash and smoke, and generates a great volume of gas.  Ballistite burns progressively, but at a rate dependent upon the composition and physical characteristics of the propellant grain, the temperature of the propellant prior to ignition and the gas pressure obtained during combustion.

  • Black Powder - Commonly known as "gunpowder," this was obsolete by the 1880s and rarely used after 1900 by the major powers as a propellant.  It did continue to be used for igniter patches on bag ammunition.  Black powder is a mixture of potassium nitrate or sodium nitrate, charcoal and sulfur.  It is hydroscopic and subject to rapid deterioration when exposed to moisture.  It is also one of the most dangerous explosives to handle because of the ease with which it is ignited by heat, friction or spark.  Black powder as a gun propellant has several disadvantages:  (1) it leaves a large amount of residue, (2) it produces large quantities of smoke, (3) it causes rapid erosion of the gun bore and (4) its velocity of reaction is too rapid, giving an abrupt hammer blow to the projectile and then rapidly decreasing energy.  This last reason is why gunpowder guns had short barrel lengths.  Muzzle velocity was generally less than 1,600 fps (488 mps).

  • Brown Powder or Cocoa Powder or Slow Burning Cocoa (SBC) - Propellant developed in the late 19th century.  An underburned straw charcoal was used in this powder and gave it the characteristic color from which it took its name.  This charcoal gave a denser and hence slower burning structure to the powder and thus permitted better regulation of pressure.  Brown powder is similar to black powder (gunpowder), each being a mixture of potassium nitrate, charcoal and sulfur, but brown powder has a lower sulfur content (3% versus 12%) and a correspondingly higher potassium nitrate content.  The reduced sulfur content results in a slower rate of deflagration (burning) and the higher potassium nitrate content supports a more complete burning of the charcoal and thus releases more energy.  The slower burning nature of brown powder allowed longer barrel lengths and thus higher muzzle velocities, with the maximum being about 2,200 fps (671 mps).  However, this propellant is notorious for producing vast quantities of smoke.

  • Cordite - A smokeless powder composed of nitroglycerin, guncotton and a petroleum substance, usually gelatinized by the addition of acetone, and the mixture then pressed into cords which resemble brown twine.  Widely used by the British with Mark I being the first version adopted by the Royal Navy in 1889.  This propellant was much more powerful and thermally efficient than gunpowder or brown powder, as shown by tests with early British 6 inch (15.2 cm) QF guns.  These replaced their 55 lbs. (25 kg) charge of brown prismatic powder with only 13 lbs. (6 kg) of Mark I propellant.  Mark I cordite did burn very hotly and was found to be detrimental to gun barrels life, as the high temperatures caused rapid wear.  For this reason, the proportions of nitroglycerine and nitrocellulose were revised in order to increase the barrel life.  This new propellant was designated MD (for Modified) and came into service in 1901.  MD charges were about 25% heavier than Mark I for the same ballistic result but doubled the life of the guns.  Both Mark I and MD were in use during World War I, and both had poor storage characteristics with their stability degrading over time.  The double-based nature of these propellants, containing a substantial amount of nitroglycerine in their composition, was significantly more susceptible to ignition than their single-base American counterparts.  These unfortunate traits led to several ships suffering magazine explosions both in action and in harbor.  A study performed after World War I found that MD tended to form highly unstable micro-sized dust particles consisting of nitrocellulose and iron pyrites.  In 1927, after a study of the German RP C/12 solventless propellant (see below) used during World War I, British chemists developed a more stable version called SC (solventless cordite, also known as solventless carbamite).  This was used to replace older propellants as rapidly as possible.  SC was used extensively during World War II and had a better safety record, although the loss of HMS Hood may be partially attributed to it.  Due to the presence of calcium in the small amount of chalk used to counteract traces of residual acids, SC had a very bright "flash," a characteristic which led to the development of flashless propellants (see below).  British cordite propellants were designated by the type and the cordage diameter size, which for MD cordite was in 0.010 inch (0.254 mm) increments and for SC cordite was in 0.001 inch (0.0254 mm) increments.  For example, MD45 meant MD-type cordite in 0.450 inch (11.4 mm) diameter cords while SC350 meant SC-type cordite in 0.350 inch (8.89 mm) diameter cords.  Some cordite in tubular form was manufactured, designated as SC T followed by two sets of numbers, with the first number indicating the external diameter and the second number indicating the internal diameter, with both numbers in 0.001 inch (0.0254 mm) increments.  Cordite in various forms was also used by the Japanese from about 1890 to the end of World War II.  Different formulations were used, most containing about 30 percent nitroglycerin and 65 percent nitrocellulose with the remainder being stabilizers.  The nominal diameter of the Japanese cords was given in units of 0.1 mm (0.004").  For example, the Japanese propellant DC80 was cordite with cords of 8 mm (0.315") diameter.  Cordite N is used as a propellant in aircraft gun ammunition.  It actually contains three main explosive components, nitroguanidine, nitrocellulose, and nitroglycerin.  Cordite N is very cool burning and produces little smoke and almost no flash.

  • Flashless Powder - Propellant formulation that reduces the amount of flame emitted from the gun muzzle.  Useful in night engagements as it does not give away the position of the firing ship.  Not really "flashless" but much less so than standard propellants.  British flashless propellants in use during World War II were produced in primarily in slotted tubular form and were of the form NF/S 164-048 with the first number indicating the external diameter and the second the internal diameter, both in 0.001 inch (0.0254 mm) increments.  However, with guns larger than 5.25" (13.3 cm), full flashless charges became too bulky for existing turret arrangements and so only the 6" (15.2 cm) Mark XXIII had been issued such charges and they were "reduced flash" or "non-blinding" rather than flashless.

  • Gun Cotton - Explosive substance formed by the nitration of cotton or some other form of cellulose.  As a projectile force, gun cotton has around six times the gas generation of an equal volume of black powder and produces less smoke and less barrel heating.  Guncotton releases about 1,100 kilocalories (Kcal) of energy per kilogram, nearly twice that of black powder, almost the same as TNT and two-thirds that of nitroglycerine.  Moist or "wet" guncotton is relatively stable but can be easily exploded by using a small amount of dry guncotton (which is sensitive to shock) to start the deflagration.  Some history about guncotton:  In 1838 the French chemist Theophile Jule Pelouze discovered that an explosive could be produced by nitrating cotton, that is, by treating cotton with nitric acid in such a way as to cause NO2 groups from the nitric acid, HNO3, to enter into combination with the cotton cellulose.  He thus produced cellulose nitrates, generally called nitrocellulose.  His explosive was the first guncotton, but it was an inconsistent mixture and was not put to practical use.  The German-Swiss chemist Christian Friedrich Sch�nbein discovered in 1845-46 that by nitrating cotton with a mixture of nitric and sulfuric acids, an explosive of good quality would result and that the nitration process could be satisfactorily controlled.  Manufacture of guncotton via his process was undertaken in several European countries, but poor quality control led to a series of disastrous explosions in many of the factories where it was being produced.  The researches of various investigators during the middle of 19th century, notably of General von Lenk in Austria and the British chemist Frederick Abel at Woolwich Arsenal (who, with James Dewar, later invented cordite), showed that the danger was due to the presence of impurities, which could be removed by careful courses of treatment.  The methods of purification which they introduced consisted principally in washing and boiling, together with pulping the material to facilitate cleansing.  In 1865, Abel was the first to safely produce good quality guncotton.

  • Nitrocellulose - See Gun Cotton, above.  Used as the base of most USN propellants.  During World War II, the primary USN propellant was a single-base, multi-tube form made up of 99.5% NC (12.6% N), 0.5% diphenylamine.  The USN used a flat, short cylindrical grain design that usually had seven perforations with the websize varying from 0.023 in (0.58 mm) for the short 3 in (7.62 cm) gun to about 0.174 in (4.42 mm) for the 16 in (40.64 cm) guns.  The USN's propellants had a good safety record partly due to the harder-to-ignite and slow burning nature of their nitrocellulose propellants and partly due to the quality of their manufacturing process.  The French also used nitrocellulose, but in a strip form.  These French propellants were designated with BM followed by a number which indicated thickness, such as BM15.  This number was somewhat arbitrary, but a larger number did indicate a thicker strip.  Early French nitrocellulose was susceptible to spontaneous ignition, but this was improved by the addition of diphenylamine as a stabilizer.

  • RP - Rohr-Pulver.  "Tube powder," the descriptive designation given to German gun propellants.  German propellants were manufactured in the form of hollow tubes.  The propellants were classified by model year and by the external and internal diameters of the tubes in millimeters.  For example, RP C/38 (14/4.9) meant a tube powder first introduced in 1938 that had an external diameter of 14 mm (0.551 in) and an internal diameter of 4.9 mm (0.193 in).  There were several compositions used from 1912 to 1945.  Earlier ones used nitroglycerin while later ones used diethylene glycol dinitrate, which was cooler-burning and less bore erosive.  All were resistant to exploding even when exposed to a hot fire.  For instance, when the small battleship Gneisenau was bombed at Kiel in 1942, over 23 tons (24 mt) of propellant was ignited in a forward magazine.  There was no explosion even though turret "Anton" was lifted at least 50 cm (20 inches) from its mounting by the gas pressure generated by the deflagration.  As noted above, the British did extensive studies of RP C/12 after World War I and developed "solventless cordite" (SC) based upon the results.

  • SD - French "solventless" propellant produced during the 1930s for 380 mm, 330 mm and a few other guns.  Like British SC, French SD appears to have been developed from a study of German RPC/12, as it was in a single tube grain and the composition was similar in its proportions of nitrocellulose, nitroglycerin and centralite.  SD19 was designed for the 330 mm guns while SD21 was used for the 380 mm guns.

  • Smokeless powder - Refers to modern gunpowder, which is really not "powder" but rather flakes of nitrocellulose and other substances.  Not really "smokeless" but much less so than black powder or brown powder.

  • USN Smokeless Propellants - In the USN smokeless powder is designated as SP and is usually a uniform ether-alcohol colloid of purified nitrocellulose with a quantity of diphenylamine (D suffix) or carbamite (ethyl centrality) (C suffix) added for stability.  Smokeless powder is generally unstable as it contains NC and two volatile substances, ether and alcohol.  Its length of usefulness depends largely on the conditions under which it is stowed.  Moisture or heat speeds its deterioration and the combination of the two is extremely damaging to the propellant.  SPDF is a flashless formulation of SPD.  SPDX is a water-dried SPD. SPDW is reworked propellant intended for target use.  SPDN is a diphenylamine-stabilized smokeless powder to which nonvolatile materials have been added to reduce its hydroscopic tendencies.  The N stands for nonhygroscopic.  SPCG is a flashless double-based propellant containing nitroglycerine and stabilized with carbamite.

  • Puff - Non-explosive projectile used for training spotters.  These produce a dense cloud of smoke approximately the size of those produced by high-explosive projectiles.

  • RAP - Rocket-Assisted Projectile.

  • Rim - The lip or flange around the case head on a cartridge case which provides purchase for the extractor claw.

  • Ring Fuze - See "Time Fuze" above.

  • Rotating Band - See "Driving Band" above.

  • Sabot - Pronounced "sa-BO."  Literally means "hoof" in French.  This is a lightweight carrier into which a projectile smaller than the barrel diameter (usually called a sub-caliber round) is centered.  The carrier fills the bore of the weapon from which the projectile is fired and is normally discarded a short distance from the muzzle.  There are two common uses for this type of ammunition. The first use is when the projectile is made from a very heavy, dense material, such as in tungsten penetrators.  Making the projectile smaller than the barrel diameter keeps the shell weight about the same as that of a conventional projectile and thus does not overstress the gun barrel.  The second use is to give a light-weight projectile a higher muzzle velocity.  This means that the same amount of propellant will throw the smaller projectile a longer distance than it will the conventional projectile.

  • Sankaidan - Japanese for "fragmentation."  Also known as "incendiary shrapnel shells" (sh�i ry�sandan).  These were AA rounds which contained hundreds of incendiary-filled steel tubes and officially designated as "Type 3 Common Shells" (3 Shiki ts�j�dan).  The incendiary filling was "Elektron" metal (45%), barium nitrate (40%) and rubber (14.3%) together with sulfur (0.5%) and stearic acid (0.2%).  "Elektron" was a trade name for a metal alloy composed primarily of magnesium (90%) with the balance being aluminum (3%), copper (3%), zinc (2%) and silicon (2%).  Besides their incendiary effect, the steel tubes also acted as shrapnel.  The Type 3 was first deployed in 1942 for 20 cm (8 in) and larger guns and in 1943 for the 12.7 cm/40 (5 in) AA and 12.7 cm/50 (5 in) DP guns.  The 46 cm (18.1 in) Type 3 projectiles for the Yamato class battleships may have been nicknamed "The Beehive" but this could be apocryphal.  A time fuze was used to set the desired bursting distance, usually about 1,000 meters (1,100 yards) after leaving the muzzle.  These projectiles were designed to burst in a 20 degree cone extending towards the oncoming aircraft with the projectile shell itself being destroyed by a bursting charge to increase the quantity of steel splinters.  The incendiary tubes ignited about half a second later and burned for five seconds at 3,000 degrees C, producing a flame about 5 meters (16 feet) long.  These shells were thought to have a larger lethal radius than did standard HE AA rounds.  The concept behind these shells was that the ship would put up a barrage pattern through which an attacking aircraft would have to fly.  However, the USN pilots considered them to be little more than fireworks and not an effective AA weapon.

  • SAP - Semi-Armor Piercing. Projectiles supplied for smaller guns for use against moderately armored targets.

  • SAPBC - Semi-Armor Piercing Ballistic Cap.  British projectile designation.  See "CPBC" above.

  • SAPER - Semi-Armor Piercing Extended Range.

  • SAPHEI-T - Semi-Armor Piercing High Explosive Incendiary Tracer.

  • SAPOM - Semi-Armor Piercing OTO Munition.

  • SAPOM-ER - Semi-Armor Piercing OTO Munition Extended Range.

  • SD - Sectional Density.  A value used for ballistic calculations.  See "Ballistic Coefficient" above.

  • Semi-fixed and/or Separate Ammunition - Semi-fixed ammunition is when the projectile and cartridge case are separate pieces but are joined together prior to firing.  This term has become interchangeable with separate ammunition, which is where the projectile does not attach to the cartridge case but they are both rammed together into the breech.  These types of ammunition were commonly used for AAA and DP type weapons used in World War II as this allowed each piece to be light enough to be manually handled.  For example, the US 5"/38 (12.7 cm) Mark 12 used a projectile with a separate brass cartridge case which held the propellant.  These were laid together in the gun's loading tray after which a rammer pushed them "home" into the breech which then closed automatically.  Technically, the 5"/38 (12.7 cm) used separate ammunition, but most descriptions of this weapon including USN official ones use the term semi-fixed.  Separate ammunition is used today on many weapons including both USA and Italian 5"/54 (12.7 cm) guns.

  • Set-back - The shock on a projectile when fired from a gun or when it strikes a target.  Used to enable many fuze mechanisms such as impact and time fuzes.

  • Shalloon - A type of coarse silk used in making propellant bags.  Also known as "cartridge cloth."

  • Shark - A British ASW projectile developed near the end of World War II.  Weighed about 96 lbs. (43.5 kg) and could be fired from any 4 inch (10.2 cm) gun.  Not known if successful in battle, but trial results were considered to be very encouraging.

  • Shell Length - This is sometimes designated as being in "calibers," similar to barrel length.  For instance, if a 16 inch (40.64 cm) shell is listed as being 4 calibers long, then this means that it is about 16 x 4 = 64 inches (1.626 m) long from nose to base.

  • Short Delay Fuze - See "Contact Fuze" above.

  • Shot - An archaic term for a solid projectile intended for penetrating armor.  Mostly replaced by AP after about 1900.

  • Shrapnel - Also known as "spherical case," this was a type of anti-personnel ammunition which consisted of a shell containing metal balls in the front and a small bursting charge at the rear which was detonated by a time fuze set to explode just before reaching the target.  This was first adopted by the British Army in 1803 and is named after the inventor, Lt. (later General) Henry Scrapnel (sometimes spelled as "Shrapnel") of the British Army.  This term has been used in the past to define shell fragments from most kinds of bursting projectiles, not necessarily anti-personnel types.  Currently, the more accurate term "shell splinter" is in general use.

  • Smoke or WP - Projectiles used to create a small smoke screen.  Usually filled with white phosphorous (WP or "Willey Pete").

  • SP - Small Pebble.  Large grain, densely packed gunpowder.  The powder was tightly pressed into a block and then broken into small pieces or "pebbles."  See "Prismatic Powder" above.

  • Special Common - USN unofficial designation of the 1920-1950 period for those Common projectiles that used both windshields and hoods.  These projectiles were designed be penetrate approximately one-third to one-half their caliber of armor.  They differed from AP projectiles by not having a cap and having a larger burster cavity.  Burster was 2.1% to 3.99% of total shell weight.

  • Spin - A standard, fin-less projectile must be spun in order to maintain stability in flight.  Under or over spun projectiles will tend to tumble in flight or not turn over at apogee and thus do not achieve good range or penetration performance.  Generally speaking, the larger the diameter or longer the projectile, the slower it can be spun, in terms of rotations per second (RPS), in order to maintain stability.

  • Splash Colors - In group actions, when more than one ship is firing on the same target, it is difficult to determine which shell splashes are from which ship.  This is important to know in order for each ship to be able to adjust its fire onto the target.  The solution was "Splash Colors," first used by the USN during Force Battle Practice in 1930 and in use by most navies during World War II.  The void space between the armor piercing cap and the windshield for AP projectiles was filled with a colored dye by the shell manufacturer.  The dye is seen when the shell impacts in the sea and colors the resulting splash - hence the name.  By using different colors, each ship could distinguish between their shells and those fired by other warships.  In the USN, the dye was a dry powder which was packaged in paper bags.  Interestingly, the USN used this dye to compensate for minor weight variations that crept in during the projectile manufacturing process.  For example, the 16 inch (40.64 cm) Mark 8 AP had a nominal 1.5 lbs. (0.68 kg) dye bag, but this was allowed to be as large as 3.0 lbs. (1.36 kg) in order to bring underweight projectiles up to the standard weight of 2,700 lbs. (1,225 kg).  Usually, a particular color was assigned to each ship.  For example, the colors used by the USS Iowa (BB-61) class battleships were as follows:

      USS Iowa - Orange
      USS New Jersey - Blue
      USS Missouri - Red
      USS Wisconsin - Green

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  • Splinter -  Fragments of a shell after detonation.

  • Squib - A firing device that burns with a flash and is used for igniting black powder or pellet powder.

  • Star Shell - See "Illum" above.

  • Super Quick Fuze - See "Contact Fuze" above.

  • Time Fuze - See "Fuzes" above.

  • TP-T - Target/Practice projectile with Tracer.

  • TTB - Target Triggered Burst.  See "Proximity Fuze" above.

  • VD - Variable Delay.  USN terminology for base fuzes designed for armor-piercing projectiles.  Complete designation was "VDXF" where "X" was the Mark number and "F" stood for fuze.  See "Fuzes" above.

  • VT - Variable Time.  See "Fuzes" above.

  • Wad - For cartridge cases using a loose powder propellant which does not fill the cartridge, a cardboard disc is placed on top of the powder and held with a distance piece to keep the propellant firmly in place.

  • Window - Projectiles containing metal foil strips, which, when scattered high in the air by the small burster charge, serve to jam radar sets by creating a multitude of images.

  • Windshield - See "Ballistic Cap" above.

  • World War I Projectile Weight - Typical World War I AP caps weighed about 5% of the total projectile weight.  World War I windscreens, when used, were tiny, only about 0.5-2% of the projectile weight.  The need for increased range caused more World War II-like long windscreens to be added to some projectiles by the end of World War I.  Burster weight was about 2.5-4% for APC, 4-6% for Common, 6-11% for HE and about 8-10% for CPC.

  • World War II Projectile Weight - Windscreens weighed 3-5% (depending on length) for most World War II projectiles, though German post-1930 L/4,4 and L/4,6 AP projectiles used brittle aluminum windscreens that only weighed about 1% of the total projectile weight.  Hoods weighed about 5%.  AP caps had more variable weights, with 8-14% being the usual range for large projectiles.  Smaller projectiles, especially U.S. Navy 6 inch (15.2 cm) and 8 in (20.3 cm) AP projectiles, had much heavier caps.  The U.S. Navy 335 lbs. (152 kg) 8 inch (20.3 cm) Mark 21 AP projectile had about a 17% cap weight, while the 130 lbs. (59 kg) 6 inch (15.2 cm) Mark 35 AP projectile had a 19-22% cap weight - both of these projectiles had the bluntest, most-hemispherical nose shapes of all projectiles in use.  Explosives made up about 2-5% for APC, although the USN used about 1.5% in their "super-heavy" projectiles.  HE or HC projectiles had about 6-8% explosive.  Some exact breakdowns:

    USN 16 inch (40.64 cm) 2,700 lbs. (1,225 kg) AP Mark 8 Mod 6 (Data from NPG Report 3-47)
       AP cap:  312 lbs. (141.5 kg) [11.6%]
       Windscreen: 32.4 lbs. (14.7 kg) [1.2%]
       Bursting charge:  40.5 lbs. (18.4 kg) [1.5%]
       Body weight (including bursting charge):  2,355.6 lbs. (1,068.5 kg) [87.2%]

    German 40.64 cm (16 inch) 2,271 lbs. (1,030 kg) Psgr. L/4,4 (mhb) (Data from NPG Report 101)
        AP cap:  363 lbs. (164.7 kg) [16%]
        Windscreen:  27 lbs. (12.3 kg) [1.2%]
        Bursting charge:  About 53.4 lbs. (24.2 kg) [2.3%]
        Body weight (including bursting charge):  1,880 lbs. (852.8 kg) [82.8%]

  • USN Projectile Markings of the World War II era


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USN Projectile Markings of the World War II era for projectiles larger than 40 mm
Click on this picture for a larger image

  • USN Bag Charge Markings of the World War II era

Bag charges were lettered in 0.375 inch (1 cm) black characters on the side of the bag opposite the lacings, with the bottom of the letters towards the ignition end of the bag.  Markings were as follows:

  1. Ammunition Lot Number
  2. Caliber and length of gun in calibers
  3. Type of charge (full, reduced, service, target, high-capacity, special)
  4. Index Number of the powder charge
  5. Number of sections per charge
  6. Initial Velocity and weight of projectile with which charge can be used
  7. (when two different weight projectiles are used) Initial Velocity and weight of other projectile
  8. The word "FLASHLESS" in 0.375 inch (1 cm) yellow characters if the charge is either a flashless type or is propellant to which flashless pellets have been added

  • USN Cartridge Case Markings of the World War II era


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In addition, cases with flashless propellant had the word "FLASHLESS" painted on the side of the case and a 0.75 inch (2 cm) "F" painted in yellow on the case head

N.G.F. stands for Naval Gun Factory, which was located at the Washington D.C. Navy Yard

Munition Identification

Ammunition is identified by markings and color-coding on the items themselves, the containers, and the packing boxes. The markings and standard nomenclature of each item, together with the lot number, FSC, NSN, DODIC, and DODAC, completely identify each item and are used to maintain accountable records. This appendix gives a basic explanation of markings and color-coding. Because color-coding is a more ready means of identification, it is given greater emphasis here.

    F-1. Markings stenciled or stamped on munitions items include all information needed for complete identification. Components in which all explosive, incendiary, or toxic materials have been simulated by substitution of inert material are identified by impressed INERT markings. Components in which all explosive, incendiary, or toxic materials have been omitted are identified by stamped EMPTY markings.
    F-2. Each item of ammunition is assigned a complete round or item lot number when it is manufactured or is at the LAP plant. See MIL-STD 1168-A for a description of the current system. See MIL-STD 1168 for a discussion of the old lot numbering system. Figure F-1 breaks down a typical ammunition lot number showing both the new and old systems.

    Figure F-1. Typical Lot Number System

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    F-3. Conventional ammunition is FSG 13. Within this group, ammunition is further broken down by two more numbers that identify the general type or family in which the item falls. Table F-1 lists the FSCs.

    Table F-1. FSC Group 13 Classes

    F-4. Each complete round or item of conventional ammunition or associated explosive component is identified by its own NSN. The first four numbers of the NSN is the FSC. It is followed by the National Item Identification Number, or NIIN, which consists of a two-number code identifying the country of manufacture and a seven-number item identification. See Figure F-2 below.

Figure F-2. Example of an NSN

F-5. A DODIC is a single letter and three numbers or, in the case of small guided missiles, two letters and two numbers. It is attached at the end of all NSNs to denote interchangeability of the item. Communications between ammunition units often use an ammunition item DODIC. See Figure F-3 for a conventional NSN with DODIC added, demonstrating interchangeability between various model numbers and the designators of an ammunition item

          Figure F-3. Sample DODIC

    F-6. The DODAC includes the FSC of the ammunition and the DODIC. The code is used on all using unit DD Form 581s, DA Form 3151-Rs, and most ammunition reports. The DODAC is used instead of the DODIC to reduce errors with ammunition transactions. See Figure F-4.

    Figure F-4. Example of a DODAC
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    F-7. The main reason ammunition is painted is to protect it from rust. However, the color of the protective coating and markings also makes ammunition easy to identify and provides some camouflage. Ammunition 20mm and larger is color-coded IAW MIL-STD 709C (see Tables F-2 and F-3). Figure F-5 shows typical markings for an artillery round of ammunition.

    Table F-2. Ammunition Color Code, MIL-STD 709C


    Fed Std No 595




    Identifies low-explosive items of components or indicates low explosive. Normally brown band around the item.



    Identifies HE ammunition or indicates presence of HE.



    Identifies chemical ammunition containing toxic chemical, incapacitating or riot control agent. Used as basic color.

    Dark red


    Identifies riot control agent filler.

    Dark green3


    Identifies toxic chemical agent filler. Used for markings and bands.



    Identifies incapacitating agent filler. Used for markings or bands.



    Identifies armor-defeating ammunition or indicates armor-defeating capability.



    Identifies countermeasure ammunition (e.g., radar echo, leaflets).

    Light green3


    Identifies screening or marking smoke ammunition.

    Light red


    Identifies incendiary ammunition or indicates highly flammable material (liquids, jellies, solids) that produce damage by fire.



    Identifies illuminating ammunition or ammunition that produces a colored light.

    Light blue


    Identifies practice ammunition.



    May be used to identify ammunition used for tracking and recovery in tests or training operations (e.g., underwater mines and torpedoes).

    Bronze, gold, brass


    Identifies completely inert ammunition for use in activities such as assembly, testing, handling, drills, etc., not to be delivered in a delivery system.

    Footnote. The following have no color-coding significance:

    1. Colors specifically applied to identify the color of smoke ammunition or pyrotechnics.
    2. Unpainted or natural color ammunition.
    3. Gray black, green, or white on underwater ammunition.
    4. Gray on air-launched missiles.
    5. Black or white when used for lettering or special marking.
    6. White on guided missiles, dispensers, and rocket launchers.

Table F-3. Application of Color Codes for Particular Ammunition Items, MIL-STD 709C






Markings 1



HE, except 20mm Olive drab Yellow Yellow 2,3,4,5


HE, 20mm Yellow Black None


Explosive binary munitions Olive drab Yellow Broken yellow6


HEP Olive drab Yellow Black


HEAT Black Yellow None


Antipersonnel and antitank mines Olive drab Yellow Yellow3


Incendiary Light red Black None


HEI Yellow Black Light red


API Black White Light red




   With bursting charge Black Yellow None


   Without bursting charge Black White None


Canister Olive drab White None


Flechette-loaded Olive drab White White7






   Filled with a toxic chemical binary nerve agent Gray Dark Green One broken dark green9,10,11




   Separate loading Olive drab White White


   Fixed or semifixed White Black None




   With low explosive to indicate functioning     Brown


   With high explosive to indicate functioning     Yellow


   Without explosive to indicate functioning     None


Screening or marking      


Smoke ammunition      


   Filled with other than WP Light green Black None


   Filled with WP Light green Light red Yellow9


      Light red12


Inert ammunition not designed to be delivered in a delivery system Bronze Black None




   Filled with a riot control agent Gray Red One red9


   Filled with an incapacitating agent Gray Violet One violet9


   Filled with a toxic chemical agent other than binary agents Gray Dark Green One dark green9


   Filled with a toxic chemical binary nerve agent Gray Dark Green One broken dark green 9,10



1. Color of the letters and figures normally used for the main identification.
2. Circumferential band of yellow diamond-shaped figures on semifixed and separate-loading improved  
    conventional munitions.
3. Circumferential band of yellow triangular-shaped figures on mass scatterable mine and loaded 
    semifixed and separate-loading ammunition.
4. Separate-loading ammunition for shipboard use has a circumferential yellow band besides yellow
5. Bombs have one yellow band except thermally protected bombs, which have two yellow bands besides
    yellow markings.
6. Circumferential broken yellow band (1/2-inch segments with 1/2-inch gaps) on explosive binary
7. Circumferential band of white diamond-shaped figures on ammunition containing flechettes.
8. Yellow band put on when the ammunition contains explosives used to fracture the projectile.
9. Yellow band put on to indicate HE burster.
10. Toxic chemical agent ammunition containing a binary nerve agent filling shown by a broken dark green
      band (1/2-inch segments separated by 1/2-inch spaces).
11. Both color applications are standard. However, for land ammunition use, separate-loading ammunition
       is olive drab for overall body color with a white band and main identification details marked white. Fixed
       and semifixed ammunition is white for overall body color with main identification details in black.
12. Separate-loading ammunition for shipboard use has black markings and a light red band.



Figure F-5. Typical Artillery Markings

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F-8. Small arms ammunition is not color-coded under MIL-STD 709C. Either the small arms projectiles or the bullet tips are painted a distinctive color so they can be identified quickly. Figures F-6 through F-8, show the color codes for types of small arms ammunition up to and including.50 caliber. For more information, see TM 9-1300-200. Significant features of the current color-coding standard are as follows:

Olive drab. With yellow markings, OD indicates an HE round. However, OD is also being used as a basic color for certain new rounds such as ICMs, the flechette antipersonnel round, and some new illumination rounds for specific field artillery weapons.
Overpacking. Ammunition overpacked in color-coded bombs, in unit dispensers, or in warheads, must not be color-coded.
Camouflage. Ammunition containing toxic chemical, incapacitating, or riot control chemical agents must never be camouflaged by painting.
Standard DOD Ammunition Color Code. MIL-STD 709C contains the standard ammunition color code for 20mm and larger ammunition. Be aware, though, that there is still ammunition coded as specified by MIL-STD 709-B and MIL-STD 709-A. If this is the case, see the appropriate MIL-STD or TM 9-1300-200.


     Figure F-6 5.56mm Cartridges

    F-7. 7.62mm Cartridges

       Figure F-8. Caliber .50 Cartridges

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Company is based at 4008-A Champion Trace Ln.,  Louisville, Kentucky 40218.
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