Monday, 28 August 2017

American Projectiles and Explosives - Projectiles and Types

American Projectiles and Explosives

United States Projectiles (and their Types)


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


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.


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.


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


These projectiles are for illuminating targets by a parachute flare.

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.


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.

The characteristics:
-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.

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

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.

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

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.

The characteristics:
-Overall Color: Red
-Sizes: 6", 8", 12", 14", 16"


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

Monday, 21 August 2017

American Projectiles and Explosives - High Explosives Inventory (Part 2)

American Projectiles and Explosives

American High Explosives (Part 2)


HBX is a new mixture designed to replace Torpex in depth bombs.  It has been loaded in the Flat Nose Bomb AN-Mk 54 Mod 1.  HBX is 40% RDX, 38% TNT, 17% Aluminum powder, 5% desensitizer.  Tests indicate that it will be about 95% to 100% as powerful as Torpex, that it will definitely be less sensitive than Torpex in both Laboratory Impact and Bullet Impact, that it will be slightly more sensitive in these respects than TNT, and that it will be about the same order as Composition B.

A difficulty with Torpex and HBX is that they produce gas and build up pressure in the case during stowage.  It has been discovered that 0.5% by weight of calcium chloride added to the mixture will absorb all the moisture and eliminate the production of gas.  It has been recommended that this percentage be added and that the resulting mixtures be designated Torpex 3 and HBX 1.

Composition A

Composition A is a mixture of 91% RDX and 98% plasticizing oil.  The oil content is sufficient to desensitize the mixture and lubricate it enough to allow it to be pressed into A.A. shells, which will probably be its principal use.  It is less sensitive than TNT in both drop and bullet impact tests.  It is appreciably more brisant and powerful as is indicated by its velocity of detonation of 27,000 feet/second at a density of 1.62.  Its Laboratory Impact Value is 105.  Its Ballistic Impact Value is over 100.  Its color may be white or buff, depending upon the color of the oil.


Tetrytol is a mixture of Tetryl and TNT (70/30 is a frequent ratio).  It is designed to obtain a Tetryl booster that may be cast.  This mixture is slightly less powerful and less sensitive than Tetryl.  Its particular use is in burster tubes for chemical bombs, in demolition blocks, and in cast shaped charges.  It cannot be used where the loaded item is immersed in hot explosive, as are the auxiliary boosters in the loading of Army bombs, because it will be remelted by the heat and separation will result.  It is approved for use in all other boosters.

Its rate of detonation is 24,000 feet/second at a density of 1.6.  Its Laboratory Impact Value is 45.  Its Bullet Impact Value is 65.  Its color is yellow.


Pentolite is a mixture of TNT and PETN, usually 50/50.  Its chief uses have been in small shell loading, in grenades, and in cast shaped charges.  It has a very high shaped-charge efficiency.  It is not as stable as TNT in stowage, and separation of PETN may occur.  Efforts should be made to keep it cool.  Its sensitivity is such that it cannot be drilled, and the fuze cavities in shells that must be drilled are poured with 90/10.  It is about the same sensitivity as Tetryl in drop tests, and more sensitive than Torpex to bullet impact.  Its brisance and power are equivalent to Composition B.

At a density of 1.65, its rate of detonation is 24,000 feet/seccond.  Its Laboratory Impact Value is 47.  Its Bullet Impact Value is 48.


Ednatol is a mixture of 57% EDNA and 43% TNT, designed to ease the shortage of RDX.  In the near future, it will be loaded as a substitute for Composition B in large G.P. bombs and fragmentation bombs.  It is somewhat more powerful than TNT and comparable in sensitivity.  It becomes soft enough to pour at 80 degrees Celsius and it is, therefore, cast.  It is entirely stable in stowage.

At a density of 1.6, it has a velocity of detonation of 24,300 feet/second.  Its Laboratory Impact Value is not given.  Its Bullet Impact Value is 83.  Its color is yellow.


PTX-1 is a new ternary explosive that is undergoing tests and may be adopted for loading in shells, bombs, grenades, mines, demolition blocks, and shaped charges.  It is a mixture of 30% RDX, 50% Tetryl, and 20% TNT.  This mixture gives a very high explosive equal to Composition B and Pentolite, and superior to Tetrytol and Ednatol.  It is less sensitive than Tetrytol and more stable.

Its velocity of detonation is 24,200 feet/second at a density of 1.66.  Its Laboratory Impact Value is 40 (est.).  Its Bullet Impact Value is not given.  Its color is yellow.


PTX-2 is another ternary explosive mixture undergoing study for possible future use.  It consists of 43.2% RDX, 28% PETN, 28.8% TNT.  It is slightly more sensitive in drop and bullet impact tests than Composition B, but a little less sensitive than Pentolite.  It is mroe brisant than any of the binary mixtures now used, which would include Composition B, and is about 10% more effective than Tteryl as a booster.  It may be used as a booster, as a main charge for fragmentation ammunition, and as a shaped charge.  Its melting point is such that it will be cast.

Its velocity of detonation is 26,200 feet/second at a density of 1.69.  Its Laboratory Impact Value is 50 (estimated).  Its Bullet Impact Value is not give.  Its color is yellow.

Composition C

Composition C-3 is the only one of the Composition C series now in production, though quantities of the others may be found int he field.  It is 77% RDX, 3% Tetryl, 4% TNNT, 1% Nitrocellulose, 5% MNT (Mononitrotoluol), 10% DNT (Dinitrotoluol).  The last two, while they are explosives, are oily liquids and plasticize the mixture.  The essential difference between Composition C-3 and Composition C-2 is the substitution of 8% Tetryl for 3% RDX, which improves the plastic qualities.  Composition C-1 was 88.3% RDX and 11.7% plasticizing oil.  The changes have been made in order to obtain a plastic composition that would meet the requirements of an ideal explosive for molded and shaped charges and that would maintain its plasticity over a wide range of temperatures and not exude oil.  Composition C-3 is about 1.35 times as powerful as TNT.

The velocite of detonation is 26,000 feet/second at a density of 1.58.  Its Laboratory Impact Value is 98.  Its Bullet Impact Value is over 100.  Its color is brown.


This is a new plastic explosive being tested for future use.  PEP-3 is a mixture of 86% PETN and 14 plasticizing oil.  PEP-2 was 85% PETN and 15% oil, but it was a little too soft.  PEP-3 is about 90% as powerful and brisant as Composition C, but its stowage stability and plastic range are much better.  Its sensitivity is about the same as Composition C, though it has much less tendency to burn.


Picratol is a mixture of 52% Explosive D and 48% TNT.  It is currently used in the 2000-lb S.A.P. Bomb M103 and is under consideration for appliance in other Army A.P.s and S.A.P.s.  Picratol's stability is about equal to that of Explosive D and TNT.

Its velocity of detonation is 22,875 feet/second at a normal loading density of 1.625.  Brisance tests, peak pressure tests, and impulse tests indicate that Picratol's destructive force is somewhat less than that of TNT, but greater than that of Explosive D.

Cyclotol 70/30

Cyclotol 70/30, a mixture of 70% RDX and 30% TNT, closely resembles Composition B except for the altered proportions of the components, and is designed as a replacement for Pentolite.  It will not, however, have Pentolite's resistance to flame.  Though results of tests are not available, Cyclotol may be anticipated to be more sensitive than Composition B, but considerably less than Pentolite.


Tritonal is composed of 80% TNT and 20% Aluminum powder and is contemplated for use in some 4,000-lb Light-Case Bombs AN-M56, in the JB-2, and in several G.P. bombs (Army 500- and 1000-lb G.P.s), where maximum blast effect is desired.  Tritonal is cast, segregation of the aluminum being prevented by a pellet loading technique.

Its Laboratory Impact Value is 89; its Bullet Impact Value is 64; and the velocite of detonation is 18,000 feet/second at a density of 1.7.  

Mercury Fulminate

Mercury Fulminate is an initiating explosive that may be used as either a primer or a dtonator.  It may be detonated by flame, friction, or percussion, and in turn detonate a booster; or it may be mixed with other materials to form a primer composition and used to ignite a propellent charge.  Its melting point is much too high for it to be cast, and it is loaded by being pressed into caps.  It has one disadvantage for military use in that it will decompose in stowage at tropical temperatures and at the end of about three years may be rendered useless.  

Compared to high explosives, it has a lower power and brisance, a fact which is indicated by its velocity of detonation of 16,500 feet/second at a density of 4.  Its Laboratory Impact Value is 8.  Its color is light yellow.

Lead Azide

Lead Azide may be used where a detonation is caused from flame, but Mercury Fulminate is generally preferred where the cap is to be set off by a firing pin.  It does have a distinct advantage over Mercury Fulminate in being completely stable in stowage at elevated temperatures.

Its rate of detonation is of the same order as Fulminate, 17,500 feet/second at a density of 4.  Its Laboratory Impact Value is 19.  Its color is white. 


This is an initiating explosive which has been used for some time in commercial detonating caps and is now being used to some extent in military types.  It is more insensitive to shock than Mercury Fulminate and Lead Azide, though it may be detonated by a sharp blow.  It will, therefore, probably be used only where it will be set off electrically or by miner's safety fuse.;  It has an advantage in being more powerful than other initiating explosives and being comparable in strength to Tetryl.  If unconfined, flame will cause it to flash but will not detonate it.  This, combined with its insensitivity to shock, makes it much more safe to handle.

Next Time: Introduction to U.S. Projectiles

Monday, 14 August 2017

American Projectiles and Explosives - High Explosives Inventory and Nomenclature (Part 1)

American Projectiles and Explosives

Introduction to American High Explosives

The information that will follow in the following weeks and months is, like with other inventories, taken from documents written at the time or soon after World War II.  These were written by British or American teams in order to categorize enemy or friendly ordnance.  This American inventory should be up to date to about February 1946, and was published in 1947.


Ordnance included was that classified as service, together with some obsolete, obsolescent, and experimental types.  The experimental items were those being actively developed in the Spring of 1946, with the probability that they would soon be standardized.

Obsolete and obsolescent equipment described was that which might still be in existence in depots or dumps at the time of writing.


When a Navy ordnance item is approved for testing, it is assigned its Mark number.  It retains this Mark number whether finally approved for service use or rejected.  Modifications to the original Mark design are treated likewise.  Army items under development as assigned "T" numbers.  If the item is standardized by the Army's Ordnance Technical Committee, the "T" designation is dropped and an "M" number is assigned.

When a modification on a "T" item is made, the change is given an "E" number: for instance, "T1E1".  If the modification is adopted as a standard item, the modification gets an "A" number in sequence of change on the standard item: for instance, "M66A1, M66A2".  The Army's Chemical Warfare Service uses "E" and "R" designations for experimental items instead of the "T" and "E" numbers, respectively, of the Ordnance Department.

For aircraft ordnance there are items which are standardized for both the Navy and the Army.  These are given the letters "AN" before their original standard name; thus, AN-Mk 33 or AN-M63A2.

Prior to June 1925, the Army's nomenclature for bombs was by a Mark and a Roman numeral, like the early Naval Mark designations, but the modifications were distinguished by the letter "M" and another Roman number (Mk I M II) where the Navy used the abbreviation "Mod", (Mk 1 Mod 2).  In 1925, the Army adopted the "M" system.  The Army-Navy Standardization Board was created in June, 1941.

American High Explosives

Two scales are employed to compare sensitivity of explosives.  The first of these is the "Laborator Impact Sensitivity" in which the ratio of the drop of a given weight necessary to detonate the explosive under discussion to the drop necessary to detonate TNT, is expressed on a percentage basis.  TNT will be given as 100.

The second is a scale of "Bullet Impact Sensitivity" with RDX rated at 0 and TNT at 100.  The other explosives are expressed in relation to these two.  Velocity of detonation varies directly with the density to which the explosive is cast or pressed, all other factors being constant.  The velocity of detonation will, therefore, be given for a definite density of loading.

TNT (Trinitrotoluol)

TNT is powerful, brisant, easy to load by casting since its melting point (Grade A) is 80.2 degrees Celsius, stable under all stowage conditions, insensitive enough to stand all normal handling, and even capable of standing bullet impact when cast.  The Navy uses it as a booster in a pressed granular form in which it is more sensitive to detonator action.

The velocity of detonation is 22,300 feet/second at a density of 1.55.  Its Laboratory Impact Value is 100.  Its Bullet Impact Value is 100.  Its color is yellow to buff.

Tetryl (Trinitrophenylmethylnitramine)

Tetryl, because of its combination of high power, brisance, and sensitivity, is the standard US booster charge, although the Navy still uses an appreciable amount of granular TNT.  It has been tried for main charge loads in small caliber projectiles, but has proved too sensitive to withstand the setback in all but 20mm.  It is used as abase charge in compound detonators.  This, in effect, makes it  a small booster in intimate contact with the initiating explosive.

The melting point of Tetryl (130 degrees Celsius) is too high to allow it to be melted and cast.  It is loaded by being mixed with small quantities of graphite or stearic acid which serve to lubricate it while it is being pressed into pellets.  Tetryl is quite safe to handle and is extremely stable in stowage.  Exposed or loose Tetryl should not be handled, as it may cause dermatitis.

The velocity of detonation is 24,400 feet/second at a density of 1.55.  Its color is light yellow, but it is usually gray because of the graphite.  It is more powerful than TNT.  Its Laboratory Impact Value is 45, and its Ballistic Impact Value is 61.

Explosive D (Ammonium Picrate)

Explosive D is the standard main charge for armor-piercing bombs and projectiles and other Navy projectiles.  While its power and brisance are slightly inferior to TNT, it is much more insensitive to shock and will stand impact on armor plate without being deflagrated.  It has two other disadvantages: (1) Its melting point is too high for it to be melted and cast, and it is therefore loaded by being pressed into cases by a hydraulic ram; (2) It reacts with metals to form extremely sensitive compounds.  This is counteracted by covering the interior of bombs or projectiles with acid-proof lacquer.

Its rate of detonation is 21,300 feet/second at a density of 1.48.  Its power and brisance are about 95% those of TNT.  Its Laboratory Impact Value is 99; its Bullet Impact Value is over 100.  Its color is yellow or yellow-orange.

RDX (Cyclonite Cyclotrimethylenetrinitramine)

RDX is the most powerful and brisant of the military high explosives, and it is considered much too sensitive to use alone.  It seems to be about half way between Tetryl and PETN in mixtures of other explosives and inerts which reduce the sensitivity to a safe range, while the mixtures have a very high brisance and power due to the RDX.  It has excellent stowage qualities, but, because of its sensitivity, it is shipped immersed in water like an initiating explosive.

The velocity of detonation is 28,000 feet/second at a density of 1.70.  Its Laboratory Impact Value is 34.  Its Bullet Impact Value is 0.  Its color is white.

PETN (Pentaerythritetetranitrate)

PETN resembles RDX in its characteristics.  It is somewhat more sensitive, but almost equal in power and brisance.  It is appreciably more sensitive to percussion and impact than Tetryl and is, therefore, not used alone as a booster, though it is being used as a base charge in some compound detonators in the way Tetryl is.  The tendency of PETN to burn is much less than that of similar explosives.   Its main use alone in the service is in primacord.  When use alone, PETN is combined with a small quantity of wax to desensitize and lubricate it, and is loaded by pressing.  It is important to know that PETN in primacord is very insensitive to flame, shock, and friction, and therefore must be detonated by a cap.

The velocity of detonation of PETN is 26,000 feet/second.  The velocity of detonation of primacord is 20,500 feet/second.  Its Laboratory Impact Value is 22.  Its Bullet Impact Value, though, not given, would be about equal to RDX (0).  Its color is white.

Haleite (EDNA, Ethylenedinitramine)

Haleite is a new explosive that probably will not be used alone, but will be used in combination with other explosives.  It is somewhat more powerful than TNT.  Its sensitivity is about the same as Tetryl.  It melts at 180 degrees Celsius, but one report states that it may detonator in the manner of an initiating explosive at that temperature or a little lower.  If loaded alone, it would be pressed.

Its velocity of detonation is 25,000 feet/second at a density of 1.5.  Its Laboratory Impact Value is 46.  Its Bullet Impact Value is not available.


Nitroguanidine is the explosive incorporated in the Navy's new double-based propellant powder, SPCG.  It is unusual in being a high explosive that is so cool in its reaction that it explodes without flash.  It is comparable in strength to TNT, and its sensitivity is of the same order.

Its rate of detonation is 24,400 feet/second at a density of 1.50.


Amatol, a substitute for TNT, is a mixture of ammonium nitrate and TNT; the percentage of ammonium nitrate, depending on the availability of TNT, has varied from 40% to 80%.  Its power and brisance decrease with the increasing percentages of nitrate, and its sensitivity decreases at the same time.  However, it is still fairly good high explosive, even when the TNT is reduced to 20%.  80/20 cannot be cast, since it is not fluid enough to pour even when TNT is molted, and it therefore must be loaded by extrusion.  Amatol has a disadvantage in that it is very hygroscopic and therefore is usually protected by a sealing pour of pure TNT.

The velocite of detonation of 50/50 is 19,700 feet/second at a density of 1.54.  Its Laboratory Impact Value is 93.  Its Bullet Impact Value is about 100.  Its color is buff.

Composition B

Composition B is intended to be used a s a more powerful replacement for TNT in the loading of some of the large size G.P. bombs, and in fragmentation bombs.  It will be used where an explosive with more power and brisance is of tactical advantage and there is no objection to a slight increase of sensitivity.

Composition B1 is a mixture of 59% RDX, 40% TNT, and 1% wax.  Composition B2 is a mixture of 60% RDX, 40% TNT.  The TNT cuts down the sensitivity of the RDX to a safe range and lowers the melting point to 81 degrees Celsius, allowing the material to be cast-loaded.

Composition B might be detonated at low order by bullet impact, but it is almost as insensitive as TNT in this respect .  It has an extremely high shaped-charge efficiency.

Its velocity of detonation is 24,500 feet/second at a density of 1.6.  Its total energy of blast in air is about 116% of that of TNT.  Its Laboratory Impact Value is 79.  Its Bullet Impact Value is 79.  Its color is yellow to brown.


Torpex is one of the explosives developed during this war to be used mainly in underwater ordnance.  The original Torpex (Torpex 1) was a mixture of 45% RDX, 37% TNT, 18% Aluminum powder (1% wax added).  It is used in mines, torpedo warheads, and depth bombs.  Torpex is more sensitive than TNT; its bullet impact and drop test sensitivities are of the same order as those of Tetryl.  It is quite stable in stowage, though it produces gas, causing pressure in the case.  It is insensitive enough to stand all normal handling.  Its melting point is low enough for it to be cast-loaded.

Its velocity of detonation is 24,000 feet/second at a density of 1.72.  It is 141% as powerful as TNT.  Its Laboratory Impact Value is 53.  Its Bullet Impact Value is 48.  Its color is slate gray.

DBX (Depth Bomb Explosive)

DBX is another aluminized RDX mixture, and its name suggests its intended use.  It is 21% RDX, 21% Aluminum Nitrate, 40% TNT, 18% Aluminum.  It was designed to replace Torpex, which is closely resembles in sensitivity, strength, brisance, and energy of shock in water, but half of the strategic RDX in Torpex is replaced by Ammonium Nitrate in DBX.  It will probably not be used, as the present supply of RDX seems adequate to meet the demand.  DBX can be cast, though its melting range of 98-105 degrees Celsius is about the upper limit.

Its velocity of detonation is 22,300 feet/second at a density of 1.68.  It is 143% as powerful as TNT under water.  Its Laboratory Impact Value is not given.  Its Bullet Impact Value is 51.  Its color is gray.

Next Time: High Explosives Inventory (Part 2)

Monday, 7 August 2017

German Projectiles - 100mm+ Mortar Rounds and Rockets

German Projectiles

H.E. Mortar Projectile, 100mm

German Designation: 10cm Wgr. 37 (Werfergranate 37)

Employment: 10cm Nb W 35

Overall length of body (projectile): 17.12 inches
Diameter of bourrelet: 4.09 inches
Type of bursting charge: TNT
Weight of bursting charge: 3.125 pounds
Total weight (projectile): 16 pounds

Markings: Painted grey green

Fuze: Wgr. Z. 38

Remarks: Information is from captured documents

Smoke Mortar Projectile, 100mm

No picture available

German Designation: 10cm Wgr. 35 Nb St (Werfgranate 35 Nebel Stahl)

Employment: 10cm Nb W 35

Overall length (projectile): 25.98 inches
Total weight (projectile): 16 pounds

Fuze: Wgr. 238

Remarks: Another round "10cm Wgr. 35 Nb TE" exists.  Information is from captured documents.

H.E. Mortar Projectile (Russian Origin), 120mm

German Designation: 12cm Wgr. 378/1, 2 or 3 (r) (Werfergranate 378/1, 2, or 3 (r))

Employment: 12cm Russian Mortar

Overall length (complete round): 30 inches
Overall length of body (projectile): 23.5 inches
Diameter of bourrelet: 4.719 inches
Width of bourrelet: 1.594 inches
Diameter of base of body: 1.562 inches
Total weight (projectile): 36 pounds

Number of fins: 12

Fuze: AZ 399 (r)

Remarks: A smoke shell exists.

H.E. Mortar Projectile, 200mm

German Designation: 20cm Wgr. 40 (Werfergranate 40)

Employment: 20cm L. Ladinswerfer

Overall length (complete round): 30.86 inches
Overall length of body (projectile): 13 inches
Diameter of body: 7.5 inches
Diameter of fins: 10.63 inches
Type of bursting charge: TNT
Weight of bursting charge: 16.94 pounds
Total weight: 49.94 pounds

Number of fins: 6

Fuze: Wgr. Z. 36

H.E. Mortar Projectile, 380mm

German Designation: 38cm Wgr. 40 (Werfergranate 40)

Employment: 38cm s. Ladingswerfer

Overall length (complete round): 59.21 inches
Overall length of body (projectile): 24.606 inches
Maximum diameter of body: 14.96 inches
Diameter of fins: 21.18 inches
Weight of bursting charge: 110 pounds
Total weight (projectile): 327.8 pounds

Number of fins: 6

Fuze: Wgr. Z. 36

Remarks: A smoke bomb exists with the designation "38cm Wgr. 40 Nb."

Rocket Propaganda Leaflet, 73mm

German Designation: 7.3cm Propaganda-granate 41

Employment: Propaganda Gesduits 41

Overall length of body (projectile): 16.1 inches
Weight of propellant: 1 pound
Type of bursting charge: Propaganda leaflets expelled by ejector C charge in flight.
Total weight (projectile): 7.2 pounds
Total weight of body: 4.5 pounds

Fuze: Time (Air burst) - Black powder train burns from propellant to black powder expeller charge.

Remarks: Consists of five parts -

1. Plastic ballistic cap 2-3/16" long which is tightly fit into;

2. A steel leaflet holder containing a 'safety pin' type spring in a split steel cylinder which it forces apart after the plastic and cardboard bore of the holder has been blown out the forward end, pushing the other parts before it, by the black powder charge in;

3. The brass base time fuze which threads;

4. Into the steel motor tube male-threaded into;

5. The base containing multiple venturis in two concentric annular rings.  Venturis in center ring vent in line of propulsion, those in outer ring have rotating inclination.

H.E. Hollow Charge Bazooka Rocket 88mm

German Designation: 8.8cm R. Pz. B. Gr.

Overall length (projectile): 25.25 inches
Diameter of body: 3.5 inches
Diameter of tail: 3.4 inches
Length of fuze housing: 6.125 inches
Type of propellant: Digl. R.P.
Total weight (projectile): 7.25 pounds

Fuze: Nose Percussion AZ 50955

Remarks: Electric ignition similar to American launcher M1 and rocket H.E. A.T. 2.36" M6A1.  Rocket and launcher of heavier weight than American counterpart.  Generates own electricity, no battery.

Smoke Rocket, 150mm

No picture available

German Designation: 15cm Wurfgranate 41 w Rn Nebel

Employment: 6 tube Neberlwerfer 41
                15cm Do-Geraet 38
                    15cm Panzerwerfer 42

Overall length (projectile): 36.43 inches
Length of body: 17 inches
Diameter of body: 4.8 inches
Maximum diameter: 6.2 inches
Weight of body: 23.5 pounds
Type of propellant: 7 sticks uni-perforated
 Weight of propellant: 14 pounds
Type of bursting charge: 30/70 Pumice.Sulphur Tri-oxide, picric burster
Weight of bursting charge: 8.5 pounds + 3.05 pounds
Total weight (projectile): 78 pounds

Fuze: Base graze fuze - DOV Zldg C/98 Np.  Electric Fuze.

Remarks: Range - 8,620 yards.  Shell at rear of rocket container.

Propellant vents through central venturi block.  26 Venturi in annular ring of assembly which forms attachment between Body Tube and Burster Container.  Can be filled with other chemicals.

H.E. Rocket, 150mm

German Designation: 15cm Wurfkoerper 41 Apreng

Employment: 6 tube Neberlwerfer 41
                15cm Do-Geraet 38
                    15cm Panzerwerfer 42

Overall length (projectile): 36.4 inches
Length of body: 12.5 inches
Diameter of bourrelet: 4.8 inches
Maximum diameter: 6.2 inches
Weight of body: 22.5 pounds
Type of propellant: DGN
 Weight of propellant: 14 pounds
Type of bursting charge: TNT
Weight of bursting charge: 4.5 pounds
Total weight (projectile): 77 pounds

Fuze: Base graze fuze - DOV.   Electric Fuze - Erz 39.

Remarks: Range - 8,620 yards.  Shell at rear of rocket container.

Propellant vents through central venturi block.  26 Venturi inclined at 140.  7 Uni-perforated sticks of propellant.

H.E. Rocket, 210mm

German Designation: 21cm Wurfkoerper 42 Spreng

Employment: 21cm Nebelwerfer

Overall length (projectile): 48.2 inches
Length of body: 15.8 inches
Diameter of body: 21.3 inches
Diameter of base: 8.38 inches
Weight of body: 90 pounds
Type of propellant: 7 Tubular sticks mounted on grid
 Weight of propellant: 40.25 pounds
Type of bursting charge: Amatol 40/60
Weight of bursting charge: 21.5 pounds
Total weight (projectile): 245 pounds

Fuze: z 23 LA 0.15
PD w/instantaneous or delay setting
Hbgr Z 35K. Mech. Time fuze S/30 (Used on aircraft)

Markings: Painted Olive Green

Remarks: Range - 9,950 yards.  Nose fuze underneath ballistic cap

Venturi tubes offset 16 degrees, 22 in annular ring in base.

H.E. Rocket, 280mm

German Designation: 28cm Wurfkoerper Spreng

Employment: 28/32 Nebelwerfer 41

Overall length (projectile): 47.6 inches
Length of body: 28.34 inches
Length of tail: 18.5 inches
Diameter of body: 10.75 inches
Weight of body: 133.5 pounds
Type of propellant: Singular stick supported on circular grid
 Weight of propellant: 14.5 pounds
Type of bursting charge: Amatol
Weight of bursting charge: 79 pounds
Total weight (projectile): 183 pounds

Fuze: Wgr. Z 50

Remarks: Range - 2,080 yards.

26 Jets in annular ring.  In tropical round the venturis are sealed over by a soldered-on, flat, tinned iron ring which blows off on ignition; rotating inclination 14 degrees.

H.E. Rocket, 300mm

German Designation: 30cm Wurfkoerper Spreng

Employment: 30 Nebelwerfer 42

Overall length (projectile): 46.5 inches
Total weight (projectile): 275 pounds

Fuze: Wgr. Z 50

Remarks: Range - 2,440 yards.

Incendiary Rocket, 320mm

German Designation: 32cm Wurfkoerper mit Flamme

Employment: 28/32 Nebelwerfer 41

Overall length (projectile): 49.2 inches
Length of body: 32.67 inches
Length of tail: 18.11 inches
Diameter of body: 13.18 inches
Weight of body: 124.5 pounds
Total weight (projectile): 173.41 pounds

Weight and type of bursting charge:
-11 gallons filling (Gas and Oil) - 87.69 pounds
-PETN blocks - 0.39 pounds

Type of propellant: One stick, six celluloid tubes in slottings around its circumference, one containing quick match with G.P. pellet at each end in central hole.
 Weight of propellant: 14.24 pounds

Fuze: Wgr. Z 50

Remarks: Range - 2,430 yards.

Single multi-perforated stick of propellant.  26 Venturi in annular ring at base, rotating inclination of 14 degrees.

Next Time: German Explosives or American Explosives/Projectiles