American Projectiles and Explosives
United States Projectiles (and their Types)
Armor-Piercing
These projectiles are designed to penetrate an equal caliber of Class A armor plate, according to test practice.
The characteristics:
-Overall Color: Black
-Sizes: 3", 6", 7", 8", 12", 14", 16"
-Explosive Filling: Explosive D
-Load Factor: 1.5% to 2.7%
-Fuzing: Base detonating or base ignition
Since it is desirable to keep the center of gravity of a projectile to the rear of (or in the immediate vicinity of) the center of the form, and as a relatively long ogive is conducive to long range, it has been advantageous to adopt light nose pieces or false ogivals termed windshields. The windshield is made of either forged mild steel, steel stamping, or aluminum. It has no special strength other than to prevent destruction during handling and set-back on firing. Windshields are screwed to the cap and are "set" by a center punch.
The armor-piercing cap is secured to the projectile by peening the skirt of the cap into notches cut into the ogive of the body and by soldering the cap to the body with a special solder of low melting point. Such solder prevents the soldering heat from drawing the temper of the body. Caps are made, in general, of the same kind of steel as are the projectile bodies. The cap acts to break down the initial strength of the armor plate, allowing the nose to reach an already strained surface. It also provides powerful circumferential support to the point and nose as they begin to penetrate the hard face, maintaining the support until they are will into the plate. In addition, the characteristically blunt outline of the cap serves to increase the effective angle of obliquity at which the projectile may hit and still penetrate.
The body is of high-quality alloy steel, carefully forged and heat-treated, since it is the part which does the actual penetration. Between the forward bourrelet and the rotating band or rear bourrelet, the diameter of the body is slightly reduced in order to provide a general clearance from the bore of the gun. The bourrelet is the bearing surface of the projectile and rides the lands of the rifle. This bearing surface is usually about one-sixth caliber in width, and its surface is generally ground to a fine finish to reduce friction and minimize wear on the lands of the gun. With the major caliber projectiles, it has become standard practice to provide a rear bourrelet or bourrelets in addition to the forward bourrelet. Rear bourrelet or bourrelets will be just before and behind the rotating band, providing better support in the gun and during the moment of ejection at the muzzle.
The rotating band has three primary functions: to seal the bore, to position and center the rear end of the projectile, and to rotate the projectile. A secondary function is to hold the projectile in place during loading and elevating for firing. The rotating band is made of commercially pure copper, or of cupro-nickel alloy containing 2.5% nickel, or in some cases a gilding metal consisting of 90% copper, 10% zinc. As a general rule, rotating bands are about one-third caliber in width.
The base plug closes off the explosive cavity and holds the base fuze or base fuze adapter. Both the base plug and the base fuze adapter, if used, are sealed in place with a gas seal ring similar to that used on the base fuze.
The base fuze is inserted through the base plug or base fuze adapter and is designed to detonate the projectile after penetration. After insertion, it is closed with a gas check ring of copper and lead put in under hydraulic pressure to prevent the propelling gases from affection the explosive filling.
Armor-piercing projectiles and common projectiles having a windshield may carry a spotting dye which colors the water on impact in order that observers may spot the fall of shot. The spotting dye in powder form is placed in the windshield before it is screwed on to the nose of the projectile. Water forces through the inlet holes covered by copper covers, dissolves the dye, and forces it out the outlet holes.
Special Common
The term "Special Common" is not an official designation of the Bureau of Ordnance, which places this and all other types of Common projectiles in a single class. The "Special Common" term, however, is widely employed by ordnance activities to describe those Common projectiles which are equipped with both windshields and hoods for windshield attachment.
These projectiles are designed to penetrate approximately one-third to one-half their caliber of armor. These projectiles differ from Armor-Piercing projectiles in that they do not have an armor-piercing cap and have a larger explosive cavity.
The characteristics:
-Overall Color: Slate Gray
-Sizes: 4", 5", 6", 8"
-Explosive Filling: Explosive D
-Load Factor: 2.1% to 3.99%
-Fuzing: Base detonating
Common
These projectiles are designed to penetrate approximately one-third their caliber of armor. They differ from Armor-Piercing and Special Common projectiles in that they have no cap or hood; the windshield threads directly to the body. Also, the explosive cavity is slightly larger.
The characteristics:
-Overall Color: Slate Gray
-Sizes: 5", 6", 8"
-Explosive Filling: Explosive D
-Load Factor: 4.4% to 5.4%
-Fuzing: Base detonating
Old Types
In addition to these Special Common and Common projectiles described above, certain types of old Common projectiles are still in use in the Naval service. These projectiles have neither cap nor windshield, are colored slate overall; are loaded with Explosive D or black powder/TNT mixture. In the latter case, they are fuzed with a base ignition fuze. This latter type is found in the 1-, 3-, and 6-pounder projectiles and in the 3-, 4-, and 5-inch sizes.
High-Capacity
These projectiles are designed to have a minimum wall thickness, and the largest explosive cavity consistent with the force of set-back. They are assembled, generally, with no-delay base fuzes, tracers, steel nose plugs, and auxiliary detonating fuzes. The steel nose plug may be removed and a point detonating or nose time fuze substituted. These projectiles are used for shore bombardment, for anti-aircraft guns, and for use against light ships and surface craft. The 3-inch High-Capacity has no base fuze.
The characteristics:
-Overall Color: Green
-Sizes: 3", 4", 5", 6", 8", 12", 14", 16"
-Explosive Filling: Explosive D, except the 3", which is TNT loaded
-Load Factor: 7% to 12.6%
-Fuzing: Only variation from the no-delay base fuzes is the Base Detonating Fuze Mk 48, with a 0.01-second delay, currently being assembled in 8" through 16" H.C. projectiles for bombardment. In the 12", 14", and 16" H.C. projectiles, there is a TNT booster beneath the auxiliary detonating fuze, requiring an addition adapter ring.
Anti-Aircraft Common
These projectiles are similar in construction to H.C. projectiles, except that a nose time or V.T. fuze is always assembled. It ca be used for anti-aircraft fire or, with the time fuze set on safe, used for bombardment.
The characteristics:
-Overall Color: Green
-Sizes: 5-inch only
-Explosive Filling: Explosive D or Composition A
-Load Factor: 13%
-Fuzing: Nose time or V.T. fuze. Auxiliary detonating fuze. No-delay base detonating fuze.
Anti-Aircraft
These projectiles vary from Anti-Aircraft Common in that no base detonating fuze is used.
The characteristics:
-Overall Color: Green
-Sizes: 3-inch only
-Explosive Filling: Composition A or TNT
-Load Factor: 5.7%
-Fuzing: Nose time fuze, auxiliary detonating fuze
The characteristics:
-Overall Color: Light Blue with two white stars
-Sizes: 3", 4", 5", 6"
-Explosive Filling: Black Powder expelling charge
-Fuzing: Nose time fuze only
The illuminating projectile is a thin case with a very small expelling charge just behind the fuze and an interior assembly of a star or candle with a parachute and a very lightly held base plug. Explosive of the expelling charge forces out the base and the interior assembly.
When the nose time fuze functions, it ignites the black powder expelling charge, which in turn ignites the star or candle. The star or candle is a steel container in which is packed under heavy pressure an illuminating compound. The closed end of the star container is attached to the strand wires of a parachute. The parachute is carefully folded, and, with its strand wires, is rolled so that upon expulsion it opens, thereby suspending the candle or star.
Because of the high velocity at which the projectile is travelling when ejection takes place, it is necessary to slow down the star-parachute assembly before the parachute becomes fully open. This is done by a center wire, one end of which secures the center of the parachute nearer to the star than when the parachute is in full release and causes the parachute to spill air, thereby preventing too great an initial strain on the parachute, After the star has burned for a few seconds, the end of the center wire is released from its point of attachment in the star can. This permits the parachute to open fully.
The characteristics:
-Overall Color: Aluminum
-Sizes: 5-inch only
-Explosive Filling: Foil strips and black powder expelling charge
-Fuzing: Nose time fuze
The characteristics:
-Overall Color: Blue Gray
-Sizes: 5-inch only
-Explosive Filling: White Phosphorus and black powder expelling charge
-Fuzing: Nose time or point detonating fuze
The characteristics:
-Overall Color: Dependent on type of projectile that is V.T.-fuzed. But, on all new projectiles, the letters V.T. are painted on the band showing the explosive filler
-Sizes: 3", 5", 6"
-Explosive Filling: Composition A is being loaded in the new V.T.-fuzed projectiles
The characteristics:
-Overall Color: Red
-Sizes: 6", 8", 12", 14", 16"
Armor-Piercing
These projectiles are designed to penetrate an equal caliber of Class A armor plate, according to test practice.
The characteristics:
-Overall Color: Black
-Sizes: 3", 6", 7", 8", 12", 14", 16"
-Explosive Filling: Explosive D
-Load Factor: 1.5% to 2.7%
-Fuzing: Base detonating or base ignition
Since it is desirable to keep the center of gravity of a projectile to the rear of (or in the immediate vicinity of) the center of the form, and as a relatively long ogive is conducive to long range, it has been advantageous to adopt light nose pieces or false ogivals termed windshields. The windshield is made of either forged mild steel, steel stamping, or aluminum. It has no special strength other than to prevent destruction during handling and set-back on firing. Windshields are screwed to the cap and are "set" by a center punch.
The armor-piercing cap is secured to the projectile by peening the skirt of the cap into notches cut into the ogive of the body and by soldering the cap to the body with a special solder of low melting point. Such solder prevents the soldering heat from drawing the temper of the body. Caps are made, in general, of the same kind of steel as are the projectile bodies. The cap acts to break down the initial strength of the armor plate, allowing the nose to reach an already strained surface. It also provides powerful circumferential support to the point and nose as they begin to penetrate the hard face, maintaining the support until they are will into the plate. In addition, the characteristically blunt outline of the cap serves to increase the effective angle of obliquity at which the projectile may hit and still penetrate.
The body is of high-quality alloy steel, carefully forged and heat-treated, since it is the part which does the actual penetration. Between the forward bourrelet and the rotating band or rear bourrelet, the diameter of the body is slightly reduced in order to provide a general clearance from the bore of the gun. The bourrelet is the bearing surface of the projectile and rides the lands of the rifle. This bearing surface is usually about one-sixth caliber in width, and its surface is generally ground to a fine finish to reduce friction and minimize wear on the lands of the gun. With the major caliber projectiles, it has become standard practice to provide a rear bourrelet or bourrelets in addition to the forward bourrelet. Rear bourrelet or bourrelets will be just before and behind the rotating band, providing better support in the gun and during the moment of ejection at the muzzle.
The rotating band has three primary functions: to seal the bore, to position and center the rear end of the projectile, and to rotate the projectile. A secondary function is to hold the projectile in place during loading and elevating for firing. The rotating band is made of commercially pure copper, or of cupro-nickel alloy containing 2.5% nickel, or in some cases a gilding metal consisting of 90% copper, 10% zinc. As a general rule, rotating bands are about one-third caliber in width.
The base plug closes off the explosive cavity and holds the base fuze or base fuze adapter. Both the base plug and the base fuze adapter, if used, are sealed in place with a gas seal ring similar to that used on the base fuze.
The base fuze is inserted through the base plug or base fuze adapter and is designed to detonate the projectile after penetration. After insertion, it is closed with a gas check ring of copper and lead put in under hydraulic pressure to prevent the propelling gases from affection the explosive filling.
Armor-piercing projectiles and common projectiles having a windshield may carry a spotting dye which colors the water on impact in order that observers may spot the fall of shot. The spotting dye in powder form is placed in the windshield before it is screwed on to the nose of the projectile. Water forces through the inlet holes covered by copper covers, dissolves the dye, and forces it out the outlet holes.
Special Common
The term "Special Common" is not an official designation of the Bureau of Ordnance, which places this and all other types of Common projectiles in a single class. The "Special Common" term, however, is widely employed by ordnance activities to describe those Common projectiles which are equipped with both windshields and hoods for windshield attachment.
These projectiles are designed to penetrate approximately one-third to one-half their caliber of armor. These projectiles differ from Armor-Piercing projectiles in that they do not have an armor-piercing cap and have a larger explosive cavity.
The characteristics:
-Overall Color: Slate Gray
-Sizes: 4", 5", 6", 8"
-Explosive Filling: Explosive D
-Load Factor: 2.1% to 3.99%
-Fuzing: Base detonating
Common
These projectiles are designed to penetrate approximately one-third their caliber of armor. They differ from Armor-Piercing and Special Common projectiles in that they have no cap or hood; the windshield threads directly to the body. Also, the explosive cavity is slightly larger.
The characteristics:
-Overall Color: Slate Gray
-Sizes: 5", 6", 8"
-Explosive Filling: Explosive D
-Load Factor: 4.4% to 5.4%
-Fuzing: Base detonating
Old Types
In addition to these Special Common and Common projectiles described above, certain types of old Common projectiles are still in use in the Naval service. These projectiles have neither cap nor windshield, are colored slate overall; are loaded with Explosive D or black powder/TNT mixture. In the latter case, they are fuzed with a base ignition fuze. This latter type is found in the 1-, 3-, and 6-pounder projectiles and in the 3-, 4-, and 5-inch sizes.
High-Capacity
These projectiles are designed to have a minimum wall thickness, and the largest explosive cavity consistent with the force of set-back. They are assembled, generally, with no-delay base fuzes, tracers, steel nose plugs, and auxiliary detonating fuzes. The steel nose plug may be removed and a point detonating or nose time fuze substituted. These projectiles are used for shore bombardment, for anti-aircraft guns, and for use against light ships and surface craft. The 3-inch High-Capacity has no base fuze.
The characteristics:
-Overall Color: Green
-Sizes: 3", 4", 5", 6", 8", 12", 14", 16"
-Explosive Filling: Explosive D, except the 3", which is TNT loaded
-Load Factor: 7% to 12.6%
-Fuzing: Only variation from the no-delay base fuzes is the Base Detonating Fuze Mk 48, with a 0.01-second delay, currently being assembled in 8" through 16" H.C. projectiles for bombardment. In the 12", 14", and 16" H.C. projectiles, there is a TNT booster beneath the auxiliary detonating fuze, requiring an addition adapter ring.
Anti-Aircraft Common
These projectiles are similar in construction to H.C. projectiles, except that a nose time or V.T. fuze is always assembled. It ca be used for anti-aircraft fire or, with the time fuze set on safe, used for bombardment.
The characteristics:
-Overall Color: Green
-Sizes: 5-inch only
-Explosive Filling: Explosive D or Composition A
-Load Factor: 13%
-Fuzing: Nose time or V.T. fuze. Auxiliary detonating fuze. No-delay base detonating fuze.
Anti-Aircraft
These projectiles vary from Anti-Aircraft Common in that no base detonating fuze is used.
The characteristics:
-Overall Color: Green
-Sizes: 3-inch only
-Explosive Filling: Composition A or TNT
-Load Factor: 5.7%
-Fuzing: Nose time fuze, auxiliary detonating fuze
Illuminating
These projectiles are for illuminating targets by a parachute flare.
-Overall Color: Light Blue with two white stars
-Sizes: 3", 4", 5", 6"
-Explosive Filling: Black Powder expelling charge
-Fuzing: Nose time fuze only
The illuminating projectile is a thin case with a very small expelling charge just behind the fuze and an interior assembly of a star or candle with a parachute and a very lightly held base plug. Explosive of the expelling charge forces out the base and the interior assembly.
When the nose time fuze functions, it ignites the black powder expelling charge, which in turn ignites the star or candle. The star or candle is a steel container in which is packed under heavy pressure an illuminating compound. The closed end of the star container is attached to the strand wires of a parachute. The parachute is carefully folded, and, with its strand wires, is rolled so that upon expulsion it opens, thereby suspending the candle or star.
Because of the high velocity at which the projectile is travelling when ejection takes place, it is necessary to slow down the star-parachute assembly before the parachute becomes fully open. This is done by a center wire, one end of which secures the center of the parachute nearer to the star than when the parachute is in full release and causes the parachute to spill air, thereby preventing too great an initial strain on the parachute, After the star has burned for a few seconds, the end of the center wire is released from its point of attachment in the star can. This permits the parachute to open fully.
Window
Window projectiles are designed to be fried from naval vessels to disrupt enemy radar operations. The projectile may be used to provide a false screen behind which our ships may maneuver or approach undetected, or to provide a false target for enemy radar. The projectile itself consists of an illuminating projectile body fitted with a nose time fuze and an expelling charge of black powder. Ignition of the expelling charge by the fuze discharges a payload of foil strips which form a reflecting cloud of radar beams.
-Overall Color: Aluminum
-Sizes: 5-inch only
-Explosive Filling: Foil strips and black powder expelling charge
-Fuzing: Nose time fuze
White Phosphorus (Smoke)
Smoke projectiles are designed for shore bombardment purposes to produce a combination of screening, anti-personnel, and slight incendiary effects. These projectiles may also be used at sea to provide a surface screen behind which vessels may maneuver undetected. The projectile consists of an illumination projectile body, fitted with a nose time fuze or point detonating fuze and a black powder expelling charge. The ignition of the expelling charge by a fuze discharges a number of white phosphorus filled steel tubes which ignite on contact with the air.
-Overall Color: Blue Gray
-Sizes: 5-inch only
-Explosive Filling: White Phosphorus and black powder expelling charge
-Fuzing: Nose time or point detonating fuze
V.T.-fuzed Projectiles
These projectiles are specially cavitized to receive the long-stemmed V.T. fuzes. They contain no tracer or nose fuze adapter, and no base fuzes are used except with the 6"/47 H.C. Projectile Mk 34. In all others, the base is sealed with a gas-checked base fuze hole plug. Other than V.T. type nose fuzes may not be employed in these projectiles. New V.T. fuzed projectiles are being filled with Composition A.
-Overall Color: Dependent on type of projectile that is V.T.-fuzed. But, on all new projectiles, the letters V.T. are painted on the band showing the explosive filler
-Sizes: 3", 5", 6"
-Explosive Filling: Composition A is being loaded in the new V.T.-fuzed projectiles
Target Projectiles
These projectiles are inexpensive productions, with ballistic traits similar to the A.P. projectiles of their caliber. They are unfuzed and contain no explosive. On some types, a dye is loaded into the windshield, which on impact with the water is funnelled out and spread through the water splash, thus distinguishing the origin of the salvo.
-Overall Color: Red
-Sizes: 6", 8", 12", 14", 16"
Gas
The same type of projectile that is used for the smoke round may be loaded with gas for chemical warfare.
Limited-use Types
Field and Bombardment: These projectiles were designed for field use or shore bombardment. They carry point detonating fuzes.
Shrapnel: Shrapnel projectiles contain steel balls which are expelled from a shrapnel case by means of a small charge of explosive, the case remaining intact. These projectiles are obsolescent.
Flat Nose: Flat nose projectiles are for use against submarines, and are designed to prevent ricocheting on water impact. These projectiles are obsolescent.
Tracer: These are special projectiles designed solely to leave a visible trace int he daytime. They do not have bursting charges. These are obsolescent.
Proof Shot: These are special projectiles designed not to ricochet on water impact and are for use in proving-ground work. It is not contemplated that more of these projectiles will be procured when the present stocks are exhausted.
"Pounder": These are for Coast Guard guns.
Next Time: Minor calibers: Colors, markings, and more
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